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The harnessing and utilization of tidal current energy have emerged as prominent topics in scientific inquiry, due to their vast untapped resource potential, leading to numerous investigations into the efficacy of hydrokinetic turbines under various operational conditions. This paper delineates the wake field characteristics and performance of horizontal axis tidal stream turbines under the influence of support structures, using a comprehensively blade-resolved computational fluid dynamics (CFDs) model that employs Reynolds-averaged Navier–Stokes (RANS) equations in combination with the RNG k-ε turbulence model. To achieve this, the study utilized experimental tank tests and numerical simulations to investigate the distribution characteristics and recuperative principles of the turbine’s wake field. The velocity distribution and energy augmentation coefficient of the wake field showed strong agreement with the experimental results. To further assess the effect of support structures on the flow field downstream of the unit and its performance, the hydrodynamic attributes of the turbine wake field were analyzed with and without support structures. The interference elicited by the support structure modified the velocity distribution of the near-wake flow field, resulting in a 4.41% decrease in the turbine’s power coefficient (Cp), significantly impacting the turbine’s instantaneous performance.

The main objective of this thesis is to evaluate the impact that inadequate maintenance on a vessel’s main engine turbocharger had on its support. As a result of its neglect, the turbocharger appears to have greater vibrations than anticipated, resulting in the failure of its supporting structure. in this thesis, the static and dynamic behavior of the turbocharger’s support has been extensively studied. The first section consists of the study of the vibration of the turbocharger during different operating conditions. It comprises the gathering of data with the use of mems accelerometers and the decomposition of the signal, so as to use it as input for the dynamic simulation. the second part of the thesis is focused on determining the behavior of the structure on both static and dynamic condition with the use of the finite element method (fem). On the static model only the weight of the turbocharger is considered, whereas on the dynamic analysis, the displacements caused by the movement of the turbocharger are introduced. In this way, it is assessed the foot’s structural behavior response to the turbocharger’s vibrations and it is determined to which extent does the stress increase from a static to a dynamic scenario.

In the context of the Design for Additive Manufacturing (DfAM), the elimination and/or reduction of support structures for the parts is a key issue for process optimization in terms of sustainability and surface quality. In this work, the assessment of the surface quality of overhanging thin walls and unsupported holes with different diameters (4, 6, 8 mm) was carried out through confocal microscopy, SEM-EDS analysis and CMM measurements. To this aim, two different types of AlSi10Mg alloy parts were produced with the L-PBF technology, having self-supporting features such as thin walls and holes with different overhang angles. The results showed that (i) unsupported, down-facing surfaces can be printed consecutively without supports up to a 30° overhang angle and with a surface roughness (Sa) ranging from 3 to 40 µm; (ii) unsupported holes can be produced as well, having a mean circularity tolerance ranging from 0.03 to 0.55 mm, regardless of the diameter value; (iii) density and microstructure analysis both revealed that the parts’ integrity was not affected by the design choices.

Eklemeli imalat, doğrudan bilgisayar destekli tasarım verisinden katman üzerine katman ekleyerek üç boyutlu parçalar oluşturmaya dayanan bir üretim teknolojisidir. Topoloji optimizasyonu sonucu elde edilen veya latis yapılarından oluşan, geleneksel üretim yöntemleri ile üretilmesi mümkün olamayan, hafifletilmiş tasarımların üretilmesinde önemli bir avantaj sağlamaktadır. Son yıllarda eklemeli imalat teknolojilerinden biri olan lazer ile toz yatağı füzyonu prosesi, işlevsel ve yüksek kaliteli metalik parçaların üretimi ile başta havacılık sanayi olmak üzere birçok endüstride kullanılmaktadır. Üç boyutlu parçanın yapı oryantasyonu, parça kalitesi, atık miktarı, üretim süresi ve maliyet gibi birçok faktör üzerinde büyük bir etkiye sahiptir. Bu çalışmada, destek yapısı miktarı ve üretim süresi gibi birbiriyle çelişebilecek iki farklı amaç fonksiyonunu eş-zamanlı olarak optimize etmek için, bir çok-amaçlı optimizasyon algoritması olan bastırılmamış sınıflandırmalı genetik algoritma-II kullanılmıştır. Destek yapısı hacmini ve teknolojinin mevcut durumunu yansıtan üretim süresini hesaplamak için tahmin yöntemleri geliştirilmiştir. Geliştirilen yöntemle yapı oryantasyonu karmaşık bir parça için optimize edilmiştir ve alternatif sonuçlar görselleştirilerek değerlendirilmiştir. Geliştirilen karar-verme yöntemi ile amaç fonksiyonlarının farklı ağırlıklarına bağlı olarak üç optimum alternatif yapı yönelimi seçilmiştir. Yapı oryantasyonu sürecini doğru bir şekilde gerçekleştirmek için gereken eklemeli imalat için tasarım bilgisi, üretim öncesi işlemlerin otomatikleştirilmesiyle, ortadan kaldırılmıştır. Böylece, destek yapısı hacmini ve üretim süresini en aza indirerek yüksek proses maliyetlerine sahip olan lazer ile toz yatağı füzyonu prosesinin erişilebilirliğine ve sürdürülebilirliğine katkı sağlanmıştır. Additive manufacturing is a production technology based on creating three-dimensional parts directly from computer-aided design data layer-by-layer. This technology provides a significant advantage in producing topologically optimized or lattices applied lightweight designs that cannot be produced with conventional manufacturing methods. In recent years, it has been used in many industries, especially in the aerospace and medical industry, with the production of functional, high-quality metallic parts with the powder bed fusion process by laser, which is one of the additive manufacturing technologies. The build orientation of the three-dimensional part has a major impact on many factors such as part quality, waste amount, production time, and cost. In this study, a multi-objective optimization is carried out using non-dominated sorting genetic algorithm-II to simultaneously optimize different objectives that may conflict with each other, such as the amount of support structure and build time. Estimation methods are developed for computing the amount of support structure and the build time, which reflect the current state of the technology. With the developed method, build orientation is optimized for a complex part, and the wide range of alternative results are visualized and evaluated. Three optimum alternative build orientations are selected depending on different weights of objectives by developed decision-making mechanism. The design for additive manufacturing knowledge required to perform the build orientation process correctly is eliminated by automating the pre-processing stage. Therefore, the contribution is made to the accessibility and sustainability of the powder bed fusion process by laser, which has high process costs by minimizing support structure volume and build time.

Italy stands out as one of the few countries in Europe to have introduced policies linking public funding for political parties to measures to enhance women’s political representation. However, such policies have proved to be flawed, failing to meet the objectives that they aimed to address. Starting from these observations, this paper opens the ‘black box’ of the policy cycle and analyses the stage of policy formulation that led to gendered party finance, to understand why such ill-defined measures were introduced in the first place. In order to do so we retrace, first, the ‘support structure’ for the adoption of gender representation policies, and identify the relevant elite arena in which the policy was initiated. Then, by analysing parliamentary votes and speeches, we analyse the alliances and the conflict that originated around the policy. We find that, if structural conditions prevented the adoption of a more intrusive policy, its poor design seems to have been the result of the weakness of the support structure for the introduction of feminist policies and of the lack of cross-party alliances among women MPs that might otherwise have promoted the legitimacy of affirmative action.

Purpose Support structures used in laser powder bed fusion are often difficult to clean from unsintered powder at the end of the process. This issue can be significantly reduced through a proper design of these auxiliary structures. This paper aims to investigate preliminary the airflow within differently oriented support structures and to provide design guidelines to enhance their cleanability, especially the depowdering of them. Design/methodology/approach This study investigates the cleanability of support structures in powder bed fusion technology. Digital models of cleaning operations were designed through computer-aided engineering systems. Simulations of the airflow running into the powder entrapped within the thin walls of auxiliary supports were implemented by computational fluid dynamics. This approach was applied to a set of randomly generated geometrical configurations to determine the air turbulence intensity depending on their design. Findings The results, which are based on the assumption that a relationship exists between turbulence and powder removal effectiveness, demonstrated that the maximum cleanability is obtainable through specific relative rotations between consecutive support structures. Furthermore, it was possible to highlight the considerable influence of the auxiliary structures next to the fluid inlet. These relevant findings establish optimal design rules for the cleanability of parts manufactured by powder bed fusion processes. Originality/value This study presents a preliminary investigation into the cleanability of support structures in laser powder bed fusion, which has not been addressed by previous literature. The results allow for a better understanding of the fluid dynamics during cleaning operations. New guidelines to enhance the cleanability of support structures are provided based on the results of simulations.

22. Machining Innovations Conference for Aerospace Industry, MIC 2022, Hannover, Germany, 30 Nov 2022 - 1 Dec 2022; SSRN eLibrary 2022, 51-58 (2022). special issue: "Proceedings of the Machining Innovations Conference for Aerospace Industry (MIC)", Published by Social Science Electronic Publ., [S.l.]

In order to study the bearing safety and influencing factors of the support structures of hydraulic tunnels in cold regions under the action of low-temperature frost heave, a mechanical model of the support structure and surrounding rock was established. Taking a hydraulic tunnel of a hydropower station in Xinjiang as the research object, a combination of field measurement and a numerical simulation method was adopted to study the bearing safety of the support structure during a period of freezing weather. Based on this model, the effects of different thermal expansion coefficients, temperature differences, and surrounding rock porosity on the bearing safety of the support structure in the low-temperature region were studied. From the calculation results, it was concluded that the simulation results of the numerical model established by using the mechanical model in this paper were in good agreement with the actual measurement results of the project. The circumferential freezing and compressive stresses at the arch waist of the supporting structure of the project were the largest, and significant plastic strain was generated near the arch waist. The displacement at the arch of the supporting structure was the largest, while the weak points were at the arch waist and arch top of the supporting structure. The coefficient of thermal expansion, greater temperature difference, and increased porosity of the surrounding rock all led to an increase in the rock freezing and swelling force to varying degrees, thus reducing the load-bearing safety of the supporting structure. The research results could provide a theoretical basis and a reliable mechanical and numerical simulation model for establishing the bearing safety of tunnels in the cold region.

This study attempted to determine the dimensional stability of maxillary and mandibular edentulous denture bases constructed using three-dimensional (3D) printing systems based on stereolithography and digital light processing according to the postcuring treatment time and the removal time of the support structure. Three-dimensional printing of the designed denture base file was performed using two types of 3D printing photocurable resin (standard gray resin (Formlabs) (Somerville, MA, USA) and MAZIC D resin (Vericom) (Anyang, Korea)) and their compatible 3D printers (Form3 (Formlabs) and Phrozen Shuffle (Phrozen) (Hsinchu City, Taiwan)). Different postcuring times (no postcuring, and 15, 30, 45, and 60 min) and times of removal of the support structure were set for each group. Data relating to the denture bases in all groups were obtained using 3D scanning with a tabletop scanner after postcuring. All acquired data were exported to 3D analysis software, and the dimensional changes during postcuring of the denture base were analyzed using RMSE (root-mean-square error) values. It could be confirmed that the dimensional changes increased with postcuring time, and the accuracy was higher in the maxilla than in the mandible. The accuracy was highest for the group in which the postcuring process was performed while the support structure was present.

This study investigates the effect of support structures on the properties of Inconel 718 (i.e., IN718) parts produced by the laser powder bed fusion (LPBF) additive manufacturing process. Specifically, the effects of support structure shape (i.e., pin-type, angled-type, cone-type) and geometry (i.e., support wall thickness, and gap) on their composition, hardness, microstructure, and material/time consumption are investigated and compared to the conventionally fabricated Inconel 718. From the microstructural analysis, the deepest melt pools appeared to be formed in the sample fabricated on top of the pin-type support structure having a relatively low wall thickness. The XRD results conveyed that a proper selection of geometrical variables for designing support structure results in elevated levels of the strengthening phases of IN718. The sample fabricated on top of the pin-type support structure showed the highest Vickers hardness value of 460.5 HV, which was even higher than what was reported for the heat-treated wrought Inconel 718 (355–385 HV). Moreover, for the thinner support wall thickness, an improvement in the hardness value of the fabricated samples was observed. This study urges a reconsideration of the common approach of selecting supports for additive manufacturing of samples when a higher quality of the as-fabricated parts is desired.

Like most additive manufacturing processes for metals, material jetting processes require support structures in order to attain full 3D capability. The support structures have to be removed in subsequent operations, which increases costs and slows down the manufacturing process. One approach to this issue is the use of water-soluble support structures made from salts that allow a fast and economic support removal. In this paper, we analyze the influence of salt support structures on material jetted aluminum parts. The salt is applied in its molten state, and because molten salts are typically corrosive substances, it is important to investigate the interaction between support and build material. Other characteristic properties of salts are high melting temperatures and low thermal conductivity, which could potentially lead to remelting of already printed structures and might influence the microstructure of aluminum that is printed on top of the salt due to low cooling rates. Three different sample geometries have been examined using optical microscopy, confocal laser scanning microscopy, energy-dispersive X-ray spectroscopy and micro-hardness testing. The results indicate that there is no distinct influence on the process with respect to remelting, micro-hardness and chemical reactions. However, a larger dendrite arm spacing is observed in aluminum that is printed on salt.

Like most additive manufacturing processes for metals, material jetting processes require support structures in order to attain full 3D capability. The support structures have to be removed in subsequent operations, which increases costs and slows down the manufacturing process. One approach to this issue is the use of water-soluble support structures made from salts that allow a fast and economic support removal. In this paper, we analyze the influence of salt support structures on material jetted aluminum parts. The salt is applied in its molten state, and because molten salts are typically corrosive substances, it is important to investigate the interaction between support and build material. Other characteristic properties of salts are high melting temperatures and low thermal conductivity, which could potentially lead to remelting of already printed structures and might influence the microstructure of aluminum that is printed on top of the salt due to low cooling rates. Three different sample geometries have been examined using optical microscopy, confocal laser scanning microscopy, energy-dispersive X-ray spectroscopy and micro-hardness testing. The results indicate that there is no distinct influence on the process with respect to remelting, micro-hardness and chemical reactions. However, a larger dendrite arm spacing is observed in aluminum that is printed on salt.

Because offshore structures are affected by various environmental loads, the risk of damage is high. As a result of ever-changing ocean environmental loads, damage to offshore structures is expected to differ from year to year. However, in previous studies, it was assumed that a relatively short period of load acts repeatedly during the design life of a structure. In this study, the residual life of an offshore wind turbine support structure was evaluated in consideration of the timing uncertainty of the ocean environmental load. Sampling points for the wind velocity, wave height, and wave period were generated using a central composites design, and a transfer function was constructed from the numerical analysis results. A simulation was performed using the joint probability model of ocean environmental loads. The stress time history was calculated by entering the load samples generated by the simulation into the transfer function. The damage to the structure was calculated using the rain-flow counting method, Goodman equation, Miner’s rule, and S-N curve. The results confirmed that the wind speed generated at a specific time could not represent the wind speed that could occur during the design life of the structure.

The article presents the results of the research conducted within the framework of the project entitled WIND-TU-PLA (ERA-NET, MARTEC II), the general aim of which was to design and analyse supporting structures for wind turbines intended for operation on the South Baltic area. The research part described in the article aimed at developing a preliminary design for a jack-up platform which can operate on water areas with depth of 40 m. The main task was to determine optimal dimensions of platform legs and the radius of their spacing. Two jack-up platform concepts differing by spacing radius and hull dimensions were designed with the intention to be used as a supporting structure for a 6-MW offshore wind turbine. For each concept, the parametric analysis was performed to determine optimal dimensions of platform legs (diameter Dleg and plating thickness tleg). Relevant calculations were performed to assess the movements of the platform with parameters given in Table 1 in conditions simulating the action of the most violent storm in recent 50 years. The obtained results, having the form of amplitudes of selected physical quantities, are shown in comprehensive charts in Fig. 6 and 7. Based on the critical stress values (corresponding to the yield stress), the area was defined in which the impact strength conditions are satisfied (Fig. 14). Then, the fatigue strength analysis was performed for two selected critical leg nodes (Fig. 12). Its results were used for defining the acceptable area with respect to structure’s fatigue (Fig. 14). Geometric parameters were determined which meet the adopted criteria, Table 6. The decisive criterion turned out to be the fatigue strength criterion, while the yield point criterion appeared to be an inactive constraint.

Several filter approaches that introduce additive manufacturing-related overhang constraints in topology optimization exist. However, a drawback of these is that exact satisfaction of overhang constraints produces sharp inward corners resulting in stress singularities. The present paper therefore modifies such filter approaches by a penalty formulation, where the choice of penalty factor regulates how closely the overhang constraint is satisfied. By appropriately choosing certain weight factors in the penalty function, the cost of support structures is also reflected in the formulation in a simple and computationally inexpensive way. The method is demonstrated by parameter studies using the classical MBB beam, using both structured and unstructured meshes. Funding Agencies|Clean Sky 2 joint undertaking under the European Unions Horizon 2020 research and innovation program [738002]; Swedens innovation agency [2016-05175]

In view of the common mine disasters such as coal and gas outburst caused by the destruction of gas and coal, the numerical model of RFPA-GAS software was used to establish a numerical model based on a gas outburst accident took place in return roadway of working face 15-17-16041 in Pingdingshan mine. The dynamic failure mechanism of coal and gas outburst under the conditions of different support strengths protection and unsupported conditions was analyzed. Four dynamic processes of coal and gas outburst were discussed, and the dynamic failure mechanism of coal and gas outburst was revealed. The results show that the outstanding effect of the roadway without support treatment is similar to that of the field, and the coal and gas outburst is obviously weakened for supported roadway. Which has effective control of the active support for the protrusion. When the support method is designed, the response mechanism of the coupled support structure should be considered. It provides some theoretical support for the gas outburst control.

Stützkonstruktionen im FLM-Verfahren besitzen mehrere Problemstellungen, die im Rahmen dieser Arbeit durch einen neuartigen Ansatz gelöst werden. Zum einen existiert keine einheitliche Lösung für die verschiedenen, als Baumaterial eingesetzten, Thermoplaste. Besonders auffallend ist dabei die durch ausgeprägte Schrumpfung und starken Lagenzusammenhalt charakterisierte Gruppe der teilkristallinen Thermoplaste, für die nur unzureichende oder gar keine Optionen zur Abstützung existieren. Zum anderen reduziert der häufige Wechsel zwischen verschiedenen Bauplatten und Haftvermittlern die Flexibilität des Verfahrens und steigert die Kosten. Es muss stets ein passendes Stütz- zum gewählten Baumaterial vorgehalten, konditioniert und eingestellt sein. Ein vereinheitlichtes Konzept für Stützkonstruktionen, welches weitestgehend unabhängig vom eingesetzten Baumaterial ist, erscheint zur Weiterwicklung des Verfahrens notwendig und sinnvoll. Im Rahmen dieser Arbeit wird eine formschlüssig wirkende Stützkonstruktion auf Basis einer Mikroverzahnung entwickelt und erprobt. Diese fixiert das Bauteil durch eine Vielzahl kleiner Formschlusselemente und erlaubt gleichzeitig eine vollflächige Abstützung der Oberfläche. Bei diesem Verfahren ist kein Stoffschluss zwischen den eingesetzten Thermoplasten erforderlich, sodass diese weitestgehend unabhängig voneinander gewählt werden können. Im Zuge der Konzeptionierung werden verschiedene Ansätze betrachtet und bewertet, von denen letztlich ein druckgeprägtes Lösungskonzept gewählt wird. Der Aufbau der Verzahnung erfolgt dabei durch den Druck der Schmelze, der diese in das Gitter der Stützkonstruktion fließen und die formschlüssigen Elemente ausprägen lässt. Im Rahmen der Herleitung werden die relevanten Einflussgrößen sowie die zu erwartenden Zusammenhänge qualitativ erarbeitet und mit Kennwerten existierender additiver Fertigungssysteme verglichen. Um die identifizierten Zusammenhänge durch ein anwendungsnahes Modell zu stützen, werden empirische Versuche mit Mitteln der statistischen Versuchsplanung durchgeführt. Nach der Charakterisierung des Versuchssystems werden zwei Versuchspläne ausgearbeitet, welche die Auswirkungen der Einflussgrößen auf jeweils flache und steile Überhangwinkel fokussieren. Durch eine Zugprüfung der auf diesen Plänen basierenden additiv gefertigten Prüfkörpern wird die Haltekraft zwischen den Probenhälften ermittelt. Eine Bewertung der Oberflächenqualität erfolgt im Anschluss. Für beide Fälle werden Modelle erarbeitet, die eine hohe Anpassungsgüte besitzen. Die gefundenen Zusammenhänge werden Anhand von Demonstratoren aus Polypropylen (PP) als teilkristallines Baumaterial und mit Glykol modifiziertem Polyethylenterephthalat (PETG) sowie Polyvinylalkohol (PVA) als Stützmaterialien validiert. An diesen Druckobjekten werden auch die manuelle Entfernung der Stützkonstruktion und das Auflösen in einem Auswaschsystem exemplarisch vorgeführt. Neben dem Einsatz als lösbare Verbindung wird auch die Eignung der Mikroverzahnung für dauerhafte formschlüssige Verbindungen im FLM-Verfahren anhand einer zusätzlichen Versuchsreihe nachgewiesen. Neben der theoretischen Herleitung des treibenden Mechanismus der Mikroverzahnung wird auch der praktische Einsatz des Verfahrens mit konventionellen additiven Fertigungssystemen beschrieben und nachgewiesen. So stehen die formschlüssigen Stützkonstruktionen einem breiten Anwenderkreis unmittelbar zur Verfügung., Support structures in the FLM process have several drawbacks which are solved in this work by a novel approach. On the one hand, there is no uniform solution for the different thermoplastics used as construction materials. Particularly notable is the group of semi-crystalline thermoplastics characterized by a pronounced shrinkage and a strong bonding between layers, for which only insufficient or no options for support exist. On the other hand, the frequent change between different build plates and bonding agents reduces the flexibility of the process and increases costs. A suitable support for the selected construction material must always be kept on hand, conditioned and adjusted. A standardized concept for support structures, which is largely independent of the construction material used, appears necessary and useful for the further development of the process. In this work, an interlocking support structure based on microserration is developed and tested. This fixes the component by means of a large number of small interlocking elements and at the same time allows the surface to be supported over its entire area. This process does not require a substance-to-substance bond between the thermoplastics used, so that they can be selected largely independently of one another. In the course of the conceptual design, various approaches are considered and evaluated, from which a pressure-formed solution concept is ultimately selected. The interlocking is built up by the pressure of the melt, which causes it to flow into the grid of the supporting structure and form the interlocking elements. In the course of the derivation, the relevant influencing variables and the expected interrelationships are qualitatively worked out and compared with characteristic values of existing additive manufacturing systems. In order to support the identified relationships by an application-oriented model, empirical experiments are carried out by statistical experimental design (DoE). After characterization of the test system, two experimental designs are developed which focus on the effects of the influencing variables on flat and steep overhang angles, respectively. Tensile testing of the additively manufactured test specimens based on these plans is used to determine the holding force between the specimen halves. An evaluation of the surface quality follows. For both cases, models are developed which have a high quality of fit. The relationships found are validated using demonstrators made of polypropylene (PP) as a semi-crystalline construction material and glycol-modified polyethylene terephthalate (PETG) and polyvinyl alcohol (PVA) as support materials. Manual removal of the support structure and dissolution in a washout system are also exemplified on these printed objects. In addition to its use as a detachable connection, the suitability of microserration for permanent form-fit connections in the FLM process is also demonstrated by means of an additional series of tests. In addition to the theoretical derivation of the driving mechanism of microserration, the practical use of the process with conventional additive manufacturing systems is described and demonstrated. Thus, the interlocking support structures are immediately available to a wide range of users.

Material jetting (MJT) is a category of additive manufacturing processes where the build material is deposited in the form of individual droplets. MJT has recently been expanded into the field of metal processing due to a potentially high printing speed at low equipment and raw material cost. For full 3D capability, support structures are needed that have to be removed after the print job. We examine water soluble salts and suitable nozzle materials to realise the printing of molten salt in a MJT process. Here, the wetting characteristics of the melt and nozzle are crucial because pronounced wetting is problematic for the ejection of droplets. A sessile-drop contact angle test stand was set up to evaluate the wetting characteristics of three salts or salt mixtures (NaCl, KCl–NaCl and NaCl–$${\hbox {Na}_{2}\hbox {CO}_{3}}$$ Na 2 CO 3 ) on six different nozzle materials (various ceramics and graphite), i.e. potential nozzle materials. The results indicate a high wetting tendency of most of the examined samples with the exception of KCl-NaCl on graphite. Application of these materials on a MJT test stand confirm the feasibility of our findings.

Višegodišnjim istraživačkim radom kandidata u oblasti geometrijske identifikacije elemenata noseće strukture pretovarnih mosnih dizalica, potvrđenim saopštenjima i publikovanim radovima na domaćim i međunarodnim naučnim konferencijama i naučnim časopisima stvorena je naučno-stručna osnova za specijalizovana istraživanja koja su prezentovana u ovoj disertaciji. Teorijskom analizom uticajnih geometrijskih parametara nosača nosećih struktura, potvrđene eksperimentalnim istraživanjima na laboratorijskim modelima, formirani su teorijski odnosi geometrijskih veličina nosača. Sadržaj disertacije je tako koncipiran da između istraženih cjelina postoji funkcionalna povezanost. U toku samog istraživačkog poduhvata, posebna pažnja je posvećena analizi uticajnih parametara geometrijskih veličina nosača sandučastog tipa na odnos savojne i torzione krutosti. Rezultati sprovedenih eksperimentalnih istraživanja na laboratorijskom modelu pokazali su visoku podudarnost sa teorijskim. Time su potvrđene polazne osnove geometrijske identifikacije noseće strukture utovarno-istovarnih kolica i mosta pretovarnih dizalica. To se najbolje potvrđuje rezultatima mjerenja i rezultatima teorijskih istraživanja odnosa krutosti nosećih ramova utovarno-istovarnih kolica cki/ckj=(kj/ki) 3/2, kao i odnosa krutosti noseće konstrukcije pretovarnih dizalica čija je oslona baza (m⋅ n), ci/cj=(mj/mi)(nj/ni) 2 , što je od posebnog značaja za nastavak istraživanja usmjerenih na dinamičku analizu nosećih struktura pretovarnih mosnih dizalica. After many years of the candidate’s research work in the field of geometric identification of the support structure elements of the cranes, confirmed by numerous papers published at the national and international scientific conferences and journals, a scientific and professional basis was created for the specialized research which has been presented in the doctoral thesis. Based on the theoretical analysis of the influential geometric parameters of the supports of the support structures, verified by experimental research on laboratory models, theoretical relations of the geometrical sizes of the supports have been formed. The content of the dissertation has such a concept that there is a functional connection between the investigated units. In the research work special attention was paid to the analysis of the parameters of geometrical sizes of the box type supports which have influence on the ratio of bending and torsional stiffness. The results of the experimental studies conducted on the laboratory model had a high compatibility with the theoretical results. Thus, the foundation of the geometric identification of the support structure of the loading-unloading trolley and the crane’s bridge was verified. This is best confirmed by the measurement results and the results of theoretical investigations of the stiffness ratio for support frames of the loading-unloading trolley cki/ckj=(kj/ki) 3/2, as well as the stiffness ratio for the support structure of the crane whose support base is (m⋅ n), ci/cj=(mj/mi)(nj/ni) 2 , which is significant for the continuation of research aimed at dynamic analysis of the support structures of the cranes.

A super-span tunnel that has the characteristics of a large excavation area, a small high-span ratio and a significant spatial effect exhibits a complex mechanical response during the excavation process. In this paper, taking the Badaling Great Wall station in Beijing, China as the engineering background, a case study of field monitoring a super-span tunnel has been presented. A typical monitoring section was selected in the super-span transition section of the tunnel and the deformation and forces of both the surrounding rock and the support structures were systematically monitored. The dynamic evolution and the spatial distribution characteristics of the monitoring data, including the internal displacement of the surrounding rock, the tunnel displacement, the contact pressure between the surrounding rock and the primary supports, the contact pressure between the primary and secondary supports, the axial forces in the bolts and cables, the internal forces in both the steel arches and the secondary supports and the internal stresses of the surrounding rock, were analyzed. The results of the monitoring and the analyses have shown that the deformation and the forces acting on both the surrounding rock and the tunnel&rsquo, s lining are directly related to the construction procedures, the geological conditions and the locations in the super-span tunnel. According to the results, a few suggestions to improve the construction of the tunnel have been proposed.

El presente artículo analiza el caso de México Unido Contra la Delincuencia (MUCD), grupo de la sociedad civil que emprendió una movilización legal para cuestionar el modelo prohibicionista en materia de drogas, en tanto consideran que éste es una de las causas primordiales de la inseguridad en México. Ante la negativa de los poderes Ejecutivo y Legislativo para establecer reformas, mucd acudió al poder Judicial, en donde cuestionó de manera indirecta la política prohibicionista del Estado mexicano. Mediante el análisis de entrevistas, documentos oficiales, así como del proyecto y sentencia de la Suprema Corte, este artículo sostiene que el éxito de la movilización radicó en la construcción de una estructura de apoyo, así como en la utilización del litigio estratégico, cuyo establecimiento de alianzas entre abogados, con vínculos sociales, profesionales y de parentesco de alto perfil jugó un papel central en la obtención de un fallo favorable de la Suprema Corte de Justicia de la Nació This article analyzes the case of Mexico United Against Crime [México Unido Contra la Delincuencia], a civil society group that undertook a legal mobilization to question the prohibitionist drug model, deeming it to be one of the main causes of insecurity in Mexico. Given the refusal of the Executive and Legislative branches to establish reforms, mucd went to the Judiciary branch, where it indirectly questioned the prohibitionist policy of the Mexican state. Through the analysis of interviews and official documents, as well as the Supreme Court project and judgment, the article maintains that the success of the mobilization was based on the construction of a support structure, as well as on the use of strategic litigation; the establishment of alliances between lawyers with high-profile social, professional and kinship ties played a central role in obtaining a favorable ruling from the Supreme Court of Justice of the Nation.

Este trabajo busca abonar a la creciente discusión sobre el uso de la movilización por parte de grupos organizados para lograr sus objetivos, entendiendo los recursos como un factor fundamental para llevarla a cabo, sostenerla y lograr el éxito. Al mismo tiempo, se aproxima a uno de los problemas más importantes en América Latina: los conflictos generados por megaproyectos, específicamente por la megaminería. La pregunta central que lo orienta es ¿cómo el Frente Amplio Opositor a Minera San Xavier (FAO) mantuvo el uso de la movilización legal? Para dar cuenta de ello, a lo largo del texto se contextualiza y explica el proceso de movilización de este movimiento social poniendo especial énfasis en la movilización legal. A partir del análisis de información primaria y secundaria, se sostiene que el FAO incursionó en la movilización legal sin la ayuda de una estructura de apoyo sólida y que, en cambio, el movimiento fue construyendo su propia estructura de apoyo en la que el papel de los abogados fue piedra angular, de manera tal que se dio un proceso de embedded legal activity. This paper seeks to discuss the use of legal mobilizations by organized groups to achieve their objectives, for which resources are seen as a fundamental factor to carry them out, sustain them and succeed. At the same time, this work addresses one of the most important problems in Latin America: the conflicts generated by mega-projects, specifically by the mega-mine industry. The central question was: How did the Frente Amplio Opositor a Minera San Xavier (FAO) maintain the use of legal mobilizations? To account for this, the mobilization process of this social movement is contextualized and analyzed throughout the text, with special emphasis on legal mobilizations. Based on the analysis of primary and secondary information, the present paper argues that the FAO entered into legal mobilizations without the help of a solid support structure and that, instead, the movement was building its own support structure in which the role of lawyers was essential in a way that allowed for a process of embedded legal activity.

In the laser powder bed fusion processes for metal additive manufacturing, a support structure is needed to fix the part to the base plate and to support overhanging regions. Currently the importance of support structure for a successful build process is often underestimated and some effects are not yet well understood. Therefore, this study investigates the fracture behavior and mechanical properties of thin additive manufactured struts using the titanium alloy Ti-6Al-4V and specific machine parameters for support structures. Tensile tests were performed for different strut diameters and the fracture surfaces were analyzed using a laser microscope and a scanning electron microscope. Additionally, the porosity was examined with micro-CT scans. The results were compared with a different set of parameters used for solid parts. The experiments revealed that struts produced with support parameters had no significantly lower tensile strength than the comparative parts. Despite that, some porosity and around two percent of defects on the fracture surface for parts using the solid parameter set have been found. Parts with support parameters show no porosity, even though the energy density is around 30% lower compared to the solid parameter set.

[ES] El objetivo de este proyecto se centra en el dimensionado de una estructura soporte de un disco parabólico de una central solar en Xàtiva. El diseño de la estructura permite el seguimiento de los rayos solares a partir de dos ejes. Además, el análisis incluye el soporte de la superficie reflectora y del elemento de transformación de potencia. El proyecto se completa, tras el cálculo de la estructura propuesta, por una definición concreta de la solución a adoptar. Dentro de la cual, se incorpora aquella documentación gráfica que define la estructura, y un análisis económico y de viabilidad del proyecto propuesto. Todo ello, con la finalidad de confeccionar un trabajo completo y equiparable a la realidad, para el diseño, proyecto y ejecución de una estructura soporte real., [CA] L'objectiu d'aquest projecte es centra en el dimensionat d'una estructura suport d'un disc parabòlic d'una central solar a Xàtiva. El disseny de l'estructura permet el seguiment dels rajos solars a partir de dos eixos. A més, l'anàlisi inclou el suport de la superfície i de l'element de transformació de potència. El projecte es completa, després del càlcul de l'estructura proposada, per una definició concreta de la solució a adoptar. Dins de la qual, s'incorpora aquella documentació gràfica que defineix l'estructura, i una anàlisi econòmic i de viabilitat del projecte proposat. Tot això, amb la finalitat de confeccionar un treball complet i equiparable a la realitat, per al disseny, projecte i execució d'una estructura suport real., [EN] The aim of this project is to design a support structure for a parabolic dish in a solar power plant in Xàtiva. The design of the structure allows the tracking of the sun's rays from two axes. In addition, the analysis includes the support of the reflective surface and the power transformation element. The project is completed, after the calculation of the proposed structure, by a concrete definition of the solution to be adopted. This includes the graphic documentation that defines the structure and an economic and viability analysis of the proposed project. All of this is done with the aim of preparing a complete job that is comparable to reality, for the design, project and execution of a real support structure.

When a traffic tunnel passes through special strata such as soft rock with high geo-stress, expansive rock, and fault fracture zones, the traditional supporting structure is often destroyed due to complicated loads, which threatens the construction and operation safety of tunnel engineering. Concrete-filled steel tubular (CFST) structure gives full play to the respective advantages of steel and concrete and has better bearing capacity and economic benefits than traditional support structure, which has achieved good results in some underground engineering applications. In order to promote the application of CFST in the construction of traffic tunnels with complex geological conditions and improve the bearing capacity of the initial supporting structure of tunnels, the influencing factors of the bearing capacity of CFST arch were studied by numerical simulation. The main achievements are as follows: (1) The load-displacement curves of CFST members under different material parameters are basically consistent. CFST members have significant restrictions on displacement in the elastic stage and have high ultimate bearing capacity. Although the bearing capacity decreases obviously after reaching the peak, it shows good extension performance. (2) The height of the steel tube section, the thickness of the steel tube wall and the grade of the core concrete have an approximately linear positive correlation with the bearing capacity of CFST arch, but the influence of these three factors on the bearing capacity of CFST arch decreases in turn, and when the grade of core concrete increases above C50, it has no significant effect on the bearing capacity of members.

Objective The aim of this study was to analyze quantified displacements of the posterior vaginal wall (PVW) on dynamic magnetic resonance imaging (MRI), which may generate hypotheses for the detailed mechanisms that underlie the development of posterior vaginal prolapse. Methods Pelvic dynamic MRI scans were obtained for 12 women with normal vaginal structure (stage 0) and 62 women with 4 consecutive stages (1-4) of posterior vaginal prolapse. Structural locations (apex vagina, distal vagina, and mid-perineal body [PB]) and equidistant points along the PVW (points 4-6 were considered as midvagina) were identified, and PVW length, straight distance of PVW, levator ani parameters (levator hiatus length [LHL], levator hiatus width [LHW], levator plate angle, anorectal angle, and M line [ML]), urogenital hiatus, and prolapse diameter were measured at rest and maximal Valsalva, respectively. The displacement of these measurements was obtained. Results From stage 0 to 2, the variables LHL, LHW, levator plate angle, anorectal angle, and ML increased gradually, but midvagina, distal vagina, and mid-PB were the opposite. From stage 2 to 3, apex vagina, midvagina, distal vaginal, mid-PB, LHL, LHW, and ML raised rapidly and peaked at stage 3, then declined at stage 4. In addition, the correlation coefficients between each measurement from stage 2 to 3 were statistically higher than those from stage 0 to 2. Conclusions Quantified displacements of the PVW and its supporting structure were shown on dynamic MRI, and the mechanical mechanisms were hypothesized regarding the interaction between pressure and the support force contributing to the deformation of the PVW and the supporting structures.

In this study different designs for a multi rotor wind turbine system (MRS) will be built up in such a way that the space frame, forming the connection between rotor nacelle assemblies and tower, will be modelled as an ideal truss work. To dimension the tube diameters and wall thicknesses, a simplified load case will be used with adjusted safety factors for material and loads. This simplified approach allows fast computations of a large variety of different support structure designs. By variation of rotor number, space frame topology, space frame depth and the positioning of yaw bearings, it is possible to gain an understanding of the optimal MRS design. As such the simplified approach is a preliminary step helping to choose a good design parameter combination for a more detailed and comprehensive analysis.

Background The paper represents the first comprehensive experimental and numerical study for engineering failure analysis and appropriate design for the permanent mechanical support system for the tomb of the Sons of Ramesses II (KV5). It is, in fact, one of the largest rock cut tombs ever found in Egypt. During the late 18th Dynasty and throughout the19th, the tombs are usually located further down the Valley some distance from the rock walls. The builders often quarried through talus slopes, such as in the case of the tomb of Sons of Ramses II. It is clear that the tomb of sons of Ramsses II is much more susceptible to surcharge geostatic loading from the overburden rock strata, rock bursting, and structural damage of support pillars and walls induced to the water and past/recent flash floods impacts caused by heavy rain in the Valley. Since some of this tomb also makes contact with the underlying shale layers, that have the potential for swelling and shrinkage under changing moisture conditions. Expansive damages to these underground structures have been widely noticed in the Valley of the Kings. This tomb tends to be the worst preserved tomb in the Valley of the Kings. The Esna shale in the valley is particularly weak and unstable. It not only posed problems to the ancient quarryman, but to the modern conservator as well. When the shale comes into contact with moisture, it expands and can literally tear a hill side apart. Results The main adjectives of the geoenvironmental and geotechnical analyses carried out in the present study are to investigate the static stability, safety margins and engineering failure of the tomb of Sons of Ramsses II (KV5) under their present conditions, against unfavorable environmental (i.e. extensive weathering due to water and flash floods impact in the past and present), utter lack of preservation, geostatic overloading of structural rock support pillars, geotechnical and extreme seismic conditions. Also to design an appropriate geotechnical support system, according to the engineering rock mass classification, in particularly the rock mass rating RMR and quality rock tunneling index Q-system. Conclusions The engineering analysis had been carried out through the following four steps: 1-Evaluation of the surrounding rocks (marl limestone) by experimental investigation and the Roclab program to obtain Hoek Brown Classification criterion, Mohr- Coulomb fit and the rock mass parameters in particular the global strength and deformation modulus. 2- Qualitative and quantitative estimations of relevant factors affecting the stability of the tomb in particularly the overburden or geostatic and dynamic loading. 3- 2D and 3D integrated geotechnical modeling of the tomb environment for stress, displacement analyses and determination of volumetric strains and plastic points using advanced codes and programs like Examine 2D and PLAXIS 3D. The numerical analysis results indicated that the safety factor of the rock pillar structural supports is 1.37 and the overstress state is 1.28 MPa. 4-Remedial and retrofitting policies and techniques, static monitoring and control systems which are necessary for the strengthening and stability enhancement of the tomb, where the rock mass classification indicated the rock mass where the KV5 is excavated is poor rock, with RMR 39 and Q value 1.87. Based on the underground engineering stable equilibrium theory and rock mass classification, three support structure techniques are provided and detailed illustrated with the case of KV5 in this study.

The design and construction of tanks used for the carriage of dangerous liquid materials fall within strict standards (i.e., EN13094:2015, R111). According to these standards, their supporting structures (Ss), used for the mounting of the tank on the freight vehicle, need to be able to sustain the developed stresses. Optimizing the number of supporting structures can lead to more efficient tank designs that allow the tank to transport more liquid material and need less time to be manufactured. In the present paper, the effect of the reduction of the number of supporting structures in (a) the structural integrity of the tank construction, (b) its dynamic behavior and (c) the load-sharing of the tank to the axles of the freight vehicle is investigated using the finite element (FE) method. As a case study a box-shaped tank mounted on a four-axle freight vehicle with a technical permissible maximum laden mass of 35 tn, five Ss are used. Four FE models with a decreasing number of Ss were built in ANSYS® 2020R1 CAE Software and their structural integrity was investigated. For each design, a feasible design was developed and evaluated in terms of structural integrity, dynamic behavior and axle load distribution. The results of the FE analysis were reviewed in terms of maximum equivalent Von Mises stress and stress developed on the welding areas. Additionally, the axle-load sharing was qualitatively assessed for all feasible designs. The main outcome of this work is that, overall, the use of two Ss leads to a more efficient design in terms of the manufacturing and the mounting of the tank construction on the vehicle and on a more efficient freight vehicle. More specifically, the reduction of the number of Ss from five to two lead to reduction of the tank tare weight by 9.6% with lower eigenfrequencies.

Розглянуто закономірності словесно-поетичного і музичного розвитку монодії з позиції фонемної та ладо-інтонаційної організації матеріалу. На прикладі жанру стихири, одного з найбільш поширених піснеспівів нотолінійної книги Ірмолой, показана звукова унікальність не лише музичного, але й вербального тексту.Відповідно в дослідженні піснеспіву враховуються наукові здобутки музикознавства та літературознавства.У детальному розборі поспівкової структури монодичного піснеспіву застосований ладо-інтонаційний аналіз, який дає змогу виявити ладову опорну структуру мелодичних рядків стихири. Такі елементи звукової організації матеріалу, як устій, головні та побічні ладові опори, нестійкі звуки допомагають охарактеризувати ладовий нахил композиції. Їх поява і повторність окреслюють звуковий простір піснеспіву та визначають музичні акценти, тобто пріоритети ладових тонів у межах оспіваного звукоряду.У статті порушується проблема розуміння звукової цілісності композиції. Увагу закцентовано на рівноправності розвитку двох пластів – музичного і вербального. І якщо розкриття специфіки музичного розвитку базується на вже усталених формах аналізу монодії, то для аналізу звукової організації словесно-поетичного тексту залучено методи із сфери літературознавства. У дослідженні вербального ряду застосовано фонемний аналіз.Виявлено, що методологічна структура і сутність фонемного аналізу дають повне право застосовувати його у сукупності з ладо-інтонаційним. Такий комплексний підхід дозволяє піднятись на новий рівень розуміння звукової організації монодичного піснеспіву., The laws of verbal-poetic and musical development of monody are considered from the standpoint of the phonological and ladaintonational organization of the material. On the receiver of the genre stichera, one of the most popular hymns of the non-linear book by Hirmoloy, the sound uniqueness of not only the musical but also the verbal text is shown. Accordingly, the research of the hymn takes into account the scientific achievements of musicology and literary criticism. In the detailed analysis of the melodic structure of the monodic chant, the intonational analysis is used, which makes it possible to determine the melodic structure of the melodic strings of the stichera. Such elements of the sound organization of the material as the mouth, the main and side frets, unstable sounds help to establish the mood of the composition more easily. Their appearance and repetition delineate the sound space of the hymn and arrange musical accents, that is, set the priorities of the fret tones within the operable scale. The article touches upon the problem of understanding the sound integrity of a composition. All attention is focused on the equality of development of two layers – musical and verbal. And if the disclosure of the specifics of musical development is based on already established forms of monody analysis, then methods from the field of literary criticism are used to analyze the sound organization of the verbal poetic text. In the study of the verbal text, a phonemic analysis is used. It is found that the methodological structure and essence of phonemic analysis gives the full right to use it in conjunction with the lado-intonation. Such an integrated approach allows us to rise to a new level of understanding of the sound organization of monodic chants., Рассмотрены закономерности словесно-поэтического и музыкального развития монодии с позиций фонологической и ладо-интонационной организации материала. На примере жанра стихиры – одного из наиболее распространенных песнопений нотолинейной книги Ирмолой – показана звуковая уникальность не только музыкального, но и вербального текста. Соответственно в исследовании песнопения учитываются научные достижения музыкознания и литературоведения. В подробном разборе попевочной структуры монодического песнопения использован ладо-интонационный анализ, который дает возможность определить ладовую опорную структуру мелодических строк стихиры. Такие элементы звуковой организации материала, как устой, главные и побочные ладовые опоры, неустойчивые звуки служат определению ладового наклонения композиции. Их появление и повторность очерчивают звуковое пространство песнопения и расставляют музыкальные акценты, то есть выставляют приоритеты ладовых тонов в рамках опеваемого звукоряда. В статье затрагивается проблема понимания звуковой целостности композиции. Все внимание акцентируется на равноправии развития двух пластов – музыкального и вербального. И если раскрытие специфики музыкального развития базируется на уже устоявшихся формах анализа монодии, то для анализа звуковой организации словесно-поэтического текста задействованы методы из сферы литературоведения. В исследовании вербального текста применен фонемный анализ. Обнаружено, что методологическая структура и суть фонемного анализа дает полное право использовать его в совокупности с ладо-интонационным. Такой комплексный подход позволяет подняться на новый уровень понимания звуковой организации монодического песнопения.

The article presents the calculation and design stages of the TLP platform serving as a supporting construction of a 6 MW offshore wind turbine. This platform is designed to anchor at sea at a depth of 60 m. The authors presented the method of parameterization and optimization of the hull geometry. For the two selected geometry variants, the load and motion calculations of the platform subjected to wind, wave and current under 50-year storm conditions were performed. The maximum load on the structure was determined in these extreme storm conditions. For these loads, the MES calculation of the designed platform was performed for the selected variant. Authors have presented a method for calculating maximum wind, wave and current stresses on the structure during the worst storm in the past 50 years. For these loads the MES endurance calculations of the designed platform were made. Based on the results of these calculations, the required structural changes and recalculations have been made in succession to the structural design of the platform, which meets the design requirements and has the required ad hoc strength. The article contains stress analysis in „difficult“ nodes of constructions and discusses ways of solving their problems. The work is part of the WIND-TU-PLA project from the NCBR Research Agreement (Agreement No. MARTECII / 1/2014).

This paper investigates efficient design of offshore wind turbine (OWT) support structures under ultimate loads and proposes three schemes to overcome excessive computer time due to many required external loads. The first is the assumption of a rigid support structure to find blade wind forces, so that these forces are only dependent on wind profiles, which limits different cases in the structural analyses. Since the blade information is often confidential in turbine companies, this two-stage analysis allows the hub force to be the input data for the support structure design. The second is using a few control loads to perform the steel design between the second and the second-last design cycles. The third is using parallel computational procedures, since all loading cases can be independently executed in different CPU cores and computers. The test cases, with 5044 loading cases, indicate that the proposed method is fully parallel and can complete the design procedures using a few personal computers within several days. Test cases include IEC 61400-3, tropical cyclone, and seismic loads, although there are many loads to be considered, steel design is governed by a limited number of load cases, which are discussed in this paper.

The U.S. Magnet Development Program (MDP) collaboration is designing a utility mechanical structure for testing various high-field superconducting dipole coils. The design uses a shell-based structure concept, which allows applying preload in two steps: During a room temperature assembly and during a cool down to a cryogenic temperature. The structure is designed to accommodate various coil designs - including Nb3Sn Cosine Theta (CT) and Canted CT magnets as well as hybrid magnets with high temperature superconductor cables. Superconducting coils, enclosed by bolted pads to form an octagonal coil pack, will be inserted into a reusable yoke-shell subassembly and precisely preloaded during the assembly using a bladder-and-key technology. Due to a differential thermal contraction between an external aluminum shell and the magnet core, the coil preload increases during the cool down up to level required for 17-T excitation. Such a reusable structure will serve as a testing fixture supporting goals of the MDP program, decreasing cost and simplifying coil performance testing at different preload levels. We present a finite-element analysis of the structure preloading various coil designs and examine the predicted coil stress at each step of the magnet assembly and excitation.

Although 3D-printing is common in dentistry, the technique does not produce the required quality for all target applications. Resin type, printing resolution, positioning, alignment, target structure, and the type and number of support structures may influence the surface roughness of printed objects, and this study investigates the effects of these variables. A stereolithographic data record was generated from a master model. Twelve printing processes were executed with a stereolithography Desktop 3D Printer, including models aligned across and parallel to the printer front as well as solid and hollow models. Three layer thicknesses were used, and in half of all processes, the models were inclined at 15&deg, For comparison, eight gypsum models and milled polyurethane models were manufactured. The mean roughness index of each model was determined with a perthometer. Surface roughness values were approximately 0.65 &micro, m (master), 0.87&ndash, 4.44 &micro, m (printed), 2.32&ndash, 2.57 &micro, m (milled), 1.72&ndash, 1.86 &micro, m (cast plaster/alginate casting), and 0.98&ndash, 1.03 &micro, m (cast plaster/polyether casting). The layer height and type and number of support structures influenced the surface roughness of printed models (p &le, 0.05), but positioning, structure, and alignment did not.

To obtain reliable estimations of the dynamic responses of high-rising marine structures such as offshore wind turbines with obvious nonzero initial conditions, traditional frequency-domain methods cannot be employed because they provide only steady-state results. A novel frequency-domain transient response estimation method for offshore wind turbines is presented in this paper. This method builds upon a recent, significant theoretical development, which found that expressions of external loads in the frequency domain can be obtained by discretizing their eigenvalues and corresponding complex coefficients rather than directly by discrete Fourier transform (DFT) analysis, which makes it possible to deal with nonzero conditions in the frequency domain. One engineering advantage of this approach is its computational efficiency, as the motion equations of the system can be solved in the frequency domain. In order to demonstrate this approach, a case of a monopile-supported wind turbine with nonzero initial conditions was investigated. The numerical results indicate that the approach matches well with the time-domain method, except for a small, earlier portion of the estimated responses. A second case study of a sophisticated, jacket support wind turbine, involving practical issues such as complex external loads and computation efficiency, is also discussed, and comparisons of the results with the time-domain method and traditional frequency-domain method using the commercial software ANSYS are included here.

This work presents the numerical modeling, simulation and analysis of a wind turbine gearset supported by a flexible structure model. Gearboxes based on epicyclic gear trains applied to wind turbines have some advantages, i.e., compactness, robustness and low maintenance requirements. The gearbox is one of its main components because it is responsible for transforming the low angular speed of the rotor into the higher operation speed of the induction generator. Failures in this component cause loss of efficiency and directly impact the energy generated. The gearbox is attached to the nacelle, which is supported by the wind turbine tower. Wind gusts and shear can cause vibration that affects the tower and the nacelle and, therefore, all the components attached to them. To model these phenomena, a detailed model of a 600 kW turbine was built using the MBDyn software. The bearing, gear and the induction generator models were implemented as user-defined modules and were further integrated into the complete model of the wind turbine. Results showed that the gearbox components were affected by the dynamic behavior of the support structure and, therefore, its influence should be accounted for in the design of wind turbines.

Die in dieser Arbeit erstellte Parameterstudie der Schnittgrößen von modellierten, in der Realität existierenden, Tragwerken beschäftigt sich insbesondere mit der Wirkungsweise der verschiedenen untersuchten Lastmodelle auf unterschiedliche Tragwerke. Hierfür werden die Ergebnisse und Teilergebnisse untereinander verglichen und erläutert. Des Weiteren werden die einzelnen Lastmodelle und die unterschiedliche Kombinatorik untersucht, hierbei wird die Statiksoftware RFEM herangezogen und die Eingabe in diesem Programm beschrieben. In der Arbeit wird auch eingehend Bezug auf die Modellierung der einzelnen Lastmodelle und deren Anwendung genommen. Zusätzlich werden die realen Lasten und die gesetzliche Lage in Österreich, Deutschland und der Europäischen Union im Bereich der Fahrzeuglasten auf Straßen werden untersucht. Im Zuge dessen sollen auch die Auswirkungen auf Bestandsbrücken verdeutlichen werden. Das Ziel der Arbeit ist es, nach eingehender Analyse des KFG Lastmodells sowie der Ermittlung von realen Flächenlasten und von realen Fahrzeugen, eine Aussage zur Bedeutung der Lastmodelle auf reale Brückentragwerke zu treffen For the purpose of this thesis, a parameter study of internal forces of modelled and existing bridge structures has been created. This study deals with the effect of different load models which were applied to different bridge structures. Therefore the final results and the partial results are compared with each other and will be described in more detail. The individual load models and their combinatorics are examined by making use of the specific software called “RFEM”. The process of entering the data into RFEM is described precisely. In this thesis a reference to the law in the EU, addressing in specific the maximum weight allowed of road cars and trucks, will be made. Moreover, distributed loads of existing road cars are calculated and compared to the different load models. The aim of this thesis is, after having conducted an in-depth analysis of the KFG load model and the calculated distributed loads, to make a statement regarding the importance of the different load models and also their impact on existing bridge structures. Abweichender Titel laut Übersetzung der Verfasserin/des Verfassers Masterarbeit Wien, FH Campus Wien 2019

This paper presents a description of an effective method for determining loads due to waves and current acting on the supporting structures of the offshore wind turbines. This method is dedicated to the structures consisting of the cylindrical or conical elements as well as (truncates) pyramids of polygon with a large number of sides (8 or more). The presented computational method is based on the Morison equation, which was originally developed only for cylindrically shaped structures. The new algorithm shown here uses the coefficients of inertia and drag forces that were calculated for non-cylindrical shapes. The analysed structure consists of segments which are truncated pyramids on the basis of a hex decagon. The inertia coefficients, CM, and drag coefficients, CD, were determined using RANSE-CFD calculations. The CFD simulations were performed for a specific range of variation of the period, and for a certain range of amplitudes of the velocity. In addition, the analysis of influence of the surface roughness on the inertia and drag coefficients was performed. In the next step, the computations of sea wave, current and wind load on supporting structure for the fifty-year storm were carried out. The simulations were performed in the time domain and as a result the function of forces distribution along the construction elements was obtained. The most unfavourable distribution of forces will be used, to analyse the strength of the structure, as the design load.

This paper presents a restoration solution of increased vibration of the fan plant's support structure. Based on vibrodiagnostic tests and dynamic analysis, a technical solution of the problem is given with additional steel bracing. There is particular emphasis on the diagnosis and forming of a dynamic model.

Additive manufacturing (AM) has developed rapidly since its inception in the 1980s. AM is perceived as an environmentally friendly and sustainable technology and has already gained a lot of attention globally. The potential freedom of design offered by AM is, however, often limited when printing complex geometries due to an inability to support the stresses inherent within the manufacturing process. Additional support structures are often needed, which leads to material, time and energy waste. Research in support structures is, therefore, of great importance for the future and further improvement of additive manufacturing. This paper aims to review the varied research that has been performed in the area of support structures. Fifty-seven publications regarding support structure optimization are selected and categorized into six groups for discussion. A framework is established in which future research into support structures can be pursued and standardized. By providing a comprehensive review and discussion on support structures, AM can be further improved and developed in terms of support waste in the future, thus, making AM a more sustainable technology.

The wind industry is determined to lower the costs of producing energy in all phases of the offshore wind project. During 2015–2016, projects achieved a levelized cost of energy (LCOE) of £97 and more recently it was announced that Ørsted guaranteed £57.5/MWh. Significant price increases on structural materials directly impact on larger scale wind projects, the overall cost of turbines, establishing effective supply chains, improving the consent procedures for new developments, governmental mechanisms and support, improving grid connections and finally reducing overall uncertainty and costs etc. The most important decisions at the planning stage of new investment are the selection of a profitable, cost-effective suitable offshore location and a support structure type, which greatly impact on the overall Life Cycle Costs (LCC). This research aims to introduce and apply a scalable framework to reveal and select the optimal offshore location deployment and support structure in Round 3 zones in the UK by considering the interplay of LCC aspects at the planning stage of development. This research produced a portfolio of five studies while developing the framework above. First, a comparative Political Economic Social Technological Legal Environmental (PESTLE) analysis on wind energy was performed. The analysis focused on Europe, Germany, the UK and Greece, where the UK was selected in this research as the world leader in offshore wind energy. Second, three state-of-the-art Multi-Objective Optimisation (MOO) algorithms were employed to discover optimum locations for an offshore wind farm. The 7-objective optimisation problem comprises of some of the most important techno-economic LCC factors that are directly linked to the physical aspects of each site. The results of Non-dominated Sorting Genetic Algorithm (NSGA II), NSGA III and SPEA 2 algorithms follow a similar trend, where NSGA III demonstrated its suitability by revealing more uniform and clear optimum non-dominated solutions, also known as Pareto Front (PF), because of its main design compared to the other optimisers. Based on their frequency of appearance in the PF solutions, Seagreen Alpha, Seagreen Bravo, Teesside C, Teesside D, and the Celtic Array South West Potential development Area were discovered as the most appropriate. Since PF includes solutions from all regions, this provides the developer with the flexibility to accordingly assign costs in different development phases, as required, and to choose whether to invest the available budget on the installation or the maintenance stage of the project. Third, in order to reveal optimum locations for UK Round 3 offshore zones and each zone individually, three different wind farm layouts and four types of turbines were considered in an 8-objective formulation, where five LCC factors are directly linked to the physical aspects and restrictions of each location. NSGA II discovered Moray Firth Eastern Development Area 1, Seagreen Alpha, Hornsea Project One, East Anglia One and Norfolk Boreas in the PF solutions. Although layouts 1 and 2 were mainly selected as optimum solutions, the extreme case (layout 3) also appeared in the PF a few times. All this demonstrates the scalability and effectiveness of the framework. Fourth, the effectiveness of coupling MOO and Multi-Criteria Decision Making (MCDM) methods is demonstrated, so as to select the optimum wind farm Round 3 location in order to help stakeholders with investment decisions. A process on the criteria selection is also introduced, and seven conflicting criteria are considered by using the two variations of Technique for the Order of Preference by Similarity to the Ideal Solution (TOPSIS) in order to rank the optimum locationsthat were discovered by NSGA II. From the prioritisation list, Seagreen Alpha was found as the best option, three times more preferable than Moray Firth Eastern Development Area 1. Fifth, experts‘ opinions were employed in an MCDM process to select the support structure type in an offshore wind farm. For comparison, six deterministic MCDM methods and their stochastic expansion were employed; WSM, WPM, TOPSIS, AHP, ELECTRE I and PROMETHEE I in order to account for uncertainties systematically. It was shown that the methods can relate to each other and can deliver similar results. The jacket and monopile support structures were ranked first in most deterministic and stochastic approaches. Overall, the effectiveness of the introduced research framework to meet the aim of the research is demonstrated. The framework combines a) a prototype techno-economic model for offshore wind farm deployment by using the LCC and geospatial analysis, b) MOO by using NSGA II and c) survey data from real-world experts within MCDM by using a deterministic and stochastic version of TOPSIS. EngD in Renewable Energy Marine Structures (REMS)

In household refrigerators, the rotational speed of a reciprocating compressor can be appropriately adjusted according to the temperature inside of the refrigerator. The lower rotational speed reduces the power consumption of the compressor. However, several natural frequencies of the compressor exist in the low rotation region, and besides, the unbalance force arising from the piston motion acts on the internal drive unit. Thereby the vibrations of the compressor are likely to be larger due to the resonance in the low rotation region. Although the compressor on the refrigerator is supported by vibration-proofing materials, such as rubber bushes, it is difficult to fully suppress the vibration transmission from the compressor to the refrigerator. In this study, therefore, a method for supporting the drive unit inside the shell, which is called “the self-standing support” is newly proposed in order to reduce the vibration of the compressor drastically. In the proposed method, a spherical support element is utilized instead of coil springs to support the drive unit. And the drive unit can maintain a stable self-standing state by acting restoring moment due to the gravity while it is directly placed on the shell. The natural frequencies of the compressor can be greatly reduced by decreasing the support stiffness for the drive unit in comparison with the support method using coil springs. Furthermore, in designing the drive unit, the application point of the exciting force is matched with the center of percussion to the contact point on the spherical support. As a consequence, the periodic restraining force acting on the contact point can be minimized. By these two features, it is possible to considerably reduce the vibration transmission from the drive unit to the shell. In the present study, a simplified model for a reciprocating compressor is treated, and the effectiveness of the self-standing support is investigated analytically and experimentally.

The importance of water availability during the WGS reaction has been extensively reported. Thus, the search of new supports able to interact with the water molecule is of great importance. In this work, a series of phosphate- type supports containing Ce, Ca and Ti have been studied, demonstrating that water interaction with the support is closely related to the textural properties, surface composition and crystal structure of the solids. Additionally, DRIFTS results showed that different interaction mechanisms with the water molecule occur depending on the support. The system containing Ca dissociates the water molecule and interacts with it via the phosphate and Ca2+ ions. However, the Ce systems retain water in its molecular form, which interacts with the solids via hydrogen bonding with the phosphate groups. On the other hand, the Ti system experiences a loss of phos- phorous, presenting a low degree of interaction with the water molecule. Additionally, the behavior of the supports with water has been successfully related to the WGS catalytic activity of the corresponding phosphate- supported Pt catalysts. Ministerio de Economía y Competitividad de España-ENE2015-66975-C3-2-R

Additive manufacturing technology has been rapidly developed and increasingly popular nowadays; its applications spread to almost every corner in our lives. However, when printing products with overhangs, support structures are often needed, resulting in extended build time, post-processing and material waste. Numerous papers have been published on reducing support structure consumption, thus minimizing the cost and manufacture time. However, there are still no benchmarking examples and criteria in the literature for support structure comparison, resulting in hard to distinguish which method is better than another, especially in the situation that they use different standards and geometries for their research. In this paper, a specific part is proposed as a standard geometry, all research with regard to support structure can compare the results based on this benchmarking part. Line and concentric support methods from Cura 2.6.2 based on an Original Prusa i3 MK2 printer are tested and demonstrated in this paper by using this benchmarking part. Published version

Manufacturing-oriented topology optimization has been extensively studied the past two decades, in particular for the conventional manufacturing methods, for example, machining and injection molding or casting. Both design and manufacturing engineers have benefited from these efforts because of the close-to-optimal and friendly-to-manufacture design solutions. Recently, additive manufacturing (AM) has received significant attention from both academia and industry. AM is characterized by producing geometrically complex components layer-by-layer, and greatly reduces the geometric complexity restrictions imposed on topology optimization by conventional manufacturing. In other words, AM can make near-full use of the freeform structural evolution of topology optimization. Even so, new rules and restrictions emerge due to the diverse and intricate AM processes, which should be carefully addressed when developing the AM-specific topology optimization algorithms. Therefore, the motivation of this perspective paper is to summarize the state-of-art topology optimization methods for a variety of AM topics. At the same time, this paper also expresses the authors’ perspectives on the challenges and opportunities in these topics. The hope is to inspire both researchers and engineers to meet these challenges with innovative solutions.

This paper presents a procedure of determining the causes of increased vibration of a fan plant and its support structure in the PUC 'Subotička toplana'. Excessive vibrations were observed following the installation of the frequency converter, thus a methodological approach of testing-analysis-diagnosis has been applied. Based on the definition of the causes of this problem, the paper also suggests possible repair procedures.

The support structure being the object of the analysis presented in the article is Tripod. According to the adopted assumptions, it is a foundation gravitationally set in the water region of 60 m in depth, not fixed to the seabed, which can be used for installing a 7MW wind turbine. Due to the lack of substantial information on designing and strength calculations of such types of structures in the world literature, authors have made an attempt to solve this problem within the framework of the abovementioned project. In the performed calculations all basic loads acting on the structure were taken into account, including: the self mass of the structure, the masses of the ballast, the tower and the turbine, as well as hydrostatic forces, and aero- and hydrodynamic forces acting on the entire object in extreme operating conditions.

В течение последнего десятилетия геометрические аспекты архитектуры произвольной формы определили область применения, которая систематически изучается и служит вдохновением для новых математических исследований. В настоящей статье обсуждаются темы, связанные с реализацией оболочек свободной формы различными способами (плоские и изогнутые панели, прямые и изогнутые элементы, кирпичная кладка и т. д.) И освещает взаимосвязь этих вопросов с теорией, в частности дискретную дифференциальную геометрию и дискретную геометрию., During the last decade, the geometric aspects of freeform architecture have defined a field of applications which is systematically explored and which conversely serves as inspiration for new mathematical research. This paper discusses topics relevant to the realization of freeform skins by various means (flat and curved panels, straight and curved members, masonry, etc.) and illuminates the interrelations of those questions with theory, in particular discrete differential geometry and discrete geometry., Международный научно-исследовательский журнал, №08(62) (2017)

By accounting for almost 25% of the capital cost of an OWT (offshore wind turbine), optimisation of support structures provides an efficient way to reduce the currently high cost of offshore wind energy. In this paper, a structural optimisation model for OWT support structures has been developed based on a coupled parametric FEA (Finite Element Analysis) and GA (Genetic Algorithm), minimising the mass of the support structure under multi-criteria constraints. Contrary to existing optimisation models for OWT support structures, the proposed model is an integrated structural optimisation model, which optimises the components of the support structure (i.e. tower, transition piece, grout and monopile) simultaneously. The outer diameters and section thicknesses along the support structure are chosen as design variables. A set of constraints based on multi-criteria design assessment is applied according to standard requirements, which includes vibration, stress, deformation, buckling, fatigue and design variable constraints. The model has been applied to the NREL (National Renewable Energy Laboratory) 5 MW OWT on an 00 (Offshore Code Comparison Collaboration) monopile. The results of the application of the integrated optimisation methodology show a 19.8% reduction in the global mass of the support structure while satisfying all the design constraints. It is demonstrated that the proposed structural optimisation model is capable of effectively and accurately determining the optimal design of OWT support structures, which significantly improves their design efficiency. (C) 2017 Elsevier Ltd. All rights reserved.

3D printers based on the additive manufacturing technology create objects layer-by-layer dropping fused material. As a consequence, strong overhangs cannot be printed because the new-come material does not find a suitable support over the last deposed layer. In these cases, one can add support structures (scaffolds) which make the object printable, to be removed at the end. In this paper, we propose a level set based method to create object-dependent support structures, specifically conceived to reduce both the amount of additional material and the printing time. We also review some open problems about 3D printing which can be of interests for the mathematical community.