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This study deals with the behaviour of duplex stainless steel bolted connections. The aim of the study is torespond to the question if the current stainless steel design specifications are able to predict the behaviourof such connections. Firstly, the net cross-section capacity of duplex stainless steel plates subjected to tensileloading are presented. They were conducted to obtain the stress–strain curves and tensile fracture behaviourused to support the finite element (FE) fracture simulations. Secondly, nonlinear FE models are developedfor duplex stainless steel bolted connections subjected to tensile loading. The FE models are validated againstexperimental data in terms of load–displacement curves, failure modes and ultimate loads. Then, a numericalparametric study that consists of 133 duplex stainless steel grade EN 1.4162 bolted connection specimens iscarried out. The failure modes of bolted connections are carefully examined, including combined tear out andbearing, bearing and net section, looking at the influence of parameters such as end distance, edge distance andspacing between the bolts in the connections. The results are compared to the design rules prescribed in thecurrent stainless steel design specifications. Generally, it is found that the Australian/New Zealand (AS/NZS),American (SEI/ASCE) Specification and European codes conservatively predict the ultimate strengths of thebolted connections, whereas the strengths predicted by the AS/NZS and SEI/ASCE specifications are overallmore accurate and less scattered.

Joining structural components in aircraft is generally performed through mechanical fastening. The interaction of bearing and bypass stresses in composite bolted joints causes a reduction in the static strength of the joint. The bearing-bypass diagram determines the bearing and net-section failure modes. This thesis work aims to provide a design methodology to develop the so-called bearing bypass diagram to predict the static strength of bolted joints in Fibre Metal Laminates. The methodology proposed is based on first principles and can be applied to generic FMLs and different joint configurations. A close match is observed with the analytical solution and existing experimental test data for GLARE-2A and GLARE-3. Apart from bearing and net-section failure modes, GLARE laminates were subjected to fastener pull-through failure. Considering the effect of secondary bending, a preliminary methodology was developed to determine the FPT failure in GLARE. Comparison of the analytical solution with the existing experimental data on GLARE revealed a close match in the trend., Aerospace Engineering

Joining structural components in aircraft is generally performed through mechanical fastening. The interaction of bearing and bypass stresses in composite bolted joints causes a reduction in the static strength of the joint. The bearing-bypass diagram determines the bearing and net-section failure modes. This thesis work aims to provide a design methodology to develop the so-called bearing bypass diagram to predict the static strength of bolted joints in Fibre Metal Laminates. The methodology proposed is based on first principles and can be applied to generic FMLs and different joint configurations. A close match is observed with the analytical solution and existing experimental test data for GLARE-2A and GLARE-3. Apart from bearing and net-section failure modes, GLARE laminates were subjected to fastener pull-through failure. Considering the effect of secondary bending, a preliminary methodology was developed to determine the FPT failure in GLARE. Comparison of the analytical solution with the existing experimental data on GLARE revealed a close match in the trend., Aerospace Engineering

This study deals with the behaviour of duplex stainless steel bolted connections. The aim of the study is torespond to the question if the current stainless steel design specifications are able to predict the behaviourof such connections. Firstly, the net cross-section capacity of duplex stainless steel plates subjected to tensileloading are presented. They were conducted to obtain the stress–strain curves and tensile fracture behaviourused to support the finite element (FE) fracture simulations. Secondly, nonlinear FE models are developedfor duplex stainless steel bolted connections subjected to tensile loading. The FE models are validated againstexperimental data in terms of load–displacement curves, failure modes and ultimate loads. Then, a numericalparametric study that consists of 133 duplex stainless steel grade EN 1.4162 bolted connection specimens iscarried out. The failure modes of bolted connections are carefully examined, including combined tear out andbearing, bearing and net section, looking at the influence of parameters such as end distance, edge distance andspacing between the bolts in the connections. The results are compared to the design rules prescribed in thecurrent stainless steel design specifications. Generally, it is found that the Australian/New Zealand (AS/NZS),American (SEI/ASCE) Specification and European codes conservatively predict the ultimate strengths of thebolted connections, whereas the strengths predicted by the AS/NZS and SEI/ASCE specifications are overallmore accurate and less scattered.

Primary aerospace composite structures are commonly assembled with bolted joints due to their ability to transfer high loads and ease of assembly. However, when bolted joints are used beyond their originally intended design life, joint strength can be significantly reduced due to the accumulation of internal damage, necessitating frequent inspections. Furthermore, internal damage in composites (delamination, matrix cracks) can continue to propagate without visual indications, thus nondestructive testing is required. As a result, maintenance can become very costly, particularly for aircraft that are in-service beyond their designed life expectancy. By establishing a comprehensive understanding of damage propagation behavior, engineers can determine which damage modes to inspect for and reduce inspection frequency. This research aims to support and improve maintenance operations, fleet management, and aircraft design practice by investigating delamination initiations and propagations in the vicinity of fastener holes within fiber-reinforced composite materials. Static and fatigue bearing were performed using novel test methods developed as part of this research for countersunk fastener joints: the modified countersunk double lap shear (DLS), single lap shear (SLS), and semi-circular notch (SCN) test configurations. DLS and SLS static and fatigue experimental test results were compared to study joint configuration, laminate stacking sequence, and loading condition effect on bearing damage initiation and growth under both static and fatigue loading. From static and fatigue tests, it was observed that major bearing damage accumulates in the straight shank region of the countersunk hole indicating most of the bearing load is carried by the straight shank region. Fatigue bearing test data showed that when the bolted hole elongates, stiffness decreases and internal delamination damage area growth becomes detectable through C-scan. Stated in reverse, if no measurable hole el

Primary aerospace composite structures are commonly assembled with bolted joints due to their ability to transfer high loads and ease of assembly. However, when bolted joints are used beyond their originally intended design life, joint strength can be significantly reduced due to the accumulation of internal damage, necessitating frequent inspections. Furthermore, internal damage in composites (delamination, matrix cracks) can continue to propagate without visual indications, thus nondestructive testing is required. As a result, maintenance can become very costly, particularly for aircraft that are in-service beyond their designed life expectancy. By establishing a comprehensive understanding of damage propagation behavior, engineers can determine which damage modes to inspect for and reduce inspection frequency. This research aims to support and improve maintenance operations, fleet management, and aircraft design practice by investigating delamination initiations and propagations in the vicinity of fastener holes within fiber-reinforced composite materials. Static and fatigue bearing were performed using novel test methods developed as part of this research for countersunk fastener joints: the modified countersunk double lap shear (DLS), single lap shear (SLS), and semi-circular notch (SCN) test configurations. DLS and SLS static and fatigue experimental test results were compared to study joint configuration, laminate stacking sequence, and loading condition effect on bearing damage initiation and growth under both static and fatigue loading. From static and fatigue tests, it was observed that major bearing damage accumulates in the straight shank region of the countersunk hole indicating most of the bearing load is carried by the straight shank region. Fatigue bearing test data showed that when the bolted hole elongates, stiffness decreases and internal delamination damage area growth becomes detectable through C-scan. Stated in reverse, if no measurable hole el

Full Text, Thesis (PhD Doctorate), Doctor of Philosophy (PhD), School of Eng & Built Env, Science, Environment, Engineering and Technology, The use of aluminium alloy members in building construction has increased worldwide in recent years, especially in areas with adverse conditions such as severe industrial and marine environments. Aluminium members can be used in the structural systems of residential, industrial and commercial buildings as purlins, floor joists, rafters, decks and wall studs. corrosion resistance, lightweight nature and high strength-to-weight ratio are some of the important advantages of aluminium members. Despite of these advantages, the elastic modulus of aluminium is only one-third that of steel, making aluminium members highly susceptible to various failure modes including bearing failure. This bearing failure, commonly known as web crippling, is one of the critical failure modes of thin-walled members including lipped channel sections that are unstiffened against flexural loads. To date, only a limited amount of research studies has been conducted to investigate the web crippling failure phenomenon for aluminium structural members, and no research has been carried out on the web crippling behaviour of roll-formed aluminium lipped channel sections. Hence, this research aims to conduct an experimental study using the new American Iron and Steel Institute (AISI) S909 test procedures and associated numerical studies for lipped channel sections under four loading conditions: End-Two- Flange (ETF), Interior-Two-Flange (ITF), End-One-Flange (EOF) and Interior-One- Flange (IOF). This research also considers both unfastened (flanges not connected to the support) and fastened (flanges connected to the support) conditions to cover all possible restrain scenarios in the real-world applications. Following extensive experimental tests, a series of finite element analyses (FEA) were performed to develop precise numerical models of all the tested aluminium lipped channel sections. The general-purpose software ABAQUS, with quasi-static explicit solver, was employed for this study since contact

Primary aerospace composite structures are commonly assembled with bolted joints due to their ability to transfer high loads and ease of assembly. However, when bolted joints are used beyond their originally intended design life, joint strength can be significantly reduced due to the accumulation of internal damage, necessitating frequent inspections. Furthermore, internal damage in composites (delamination, matrix cracks) can continue to propagate without visual indications, thus nondestructive testing is required. As a result, maintenance can become very costly, particularly for aircraft that are in-service beyond their designed life expectancy. By establishing a comprehensive understanding of damage propagation behavior, engineers can determine which damage modes to inspect for and reduce inspection frequency. This research aims to support and improve maintenance operations, fleet management, and aircraft design practice by investigating delamination initiations and propagations in the vicinity of fastener holes within fiber-reinforced composite materials. Static and fatigue bearing were performed using novel test methods developed as part of this research for countersunk fastener joints: the modified countersunk double lap shear (DLS), single lap shear (SLS), and semi-circular notch (SCN) test configurations. DLS and SLS static and fatigue experimental test results were compared to study joint configuration, laminate stacking sequence, and loading condition effect on bearing damage initiation and growth under both static and fatigue loading. From static and fatigue tests, it was observed that major bearing damage accumulates in the straight shank region of the countersunk hole indicating most of the bearing load is carried by the straight shank region. Fatigue bearing test data showed that when the bolted hole elongates, stiffness decreases and internal delamination damage area growth becomes detectable through C-scan. Stated in reverse, if no measurable hole el

[EN] In order to improve the operationality and the serviceability levels of passenger ships at the current Poniente's wharf of the Port of Palma, the Port Authority of the Balearic Islands has designed an extension of the berth and the outer yard. The perimeter of the intended outer yard is surrounded by reinforced concrete floating caissons placed on a rockfill berm foundation. Using the original design as a starting point, the purpose of this study is to analyze the economic impact in terms of direct costs resulting from an alternative proposal where the use of the wharf changes. Thus, the study will evaluate the commercial use of container ships keeping the same structural typology of the wharf and the location of the berth. Once the proper actions in the design are set, the study will also undertake a structural optimization and geometrical adjustments. The current technological developments in terms of the construction process of floating caissons will be considered so as to decrease both the direct and indirect costs of the project., [CA] Amb l'objecte de millorar l'operativitat i els nivells de servei a bucs comercials de passatgers de l'actual Moll de Ponent del Port de Palma, l'Autoritat Portuària de Balears ha projectat una prolongació de la línia d'atracada amb la corresponent ampliació d'esplanada adjacent. El perímetre de l'esplanada projectada està conformada per calaixos flotants de formigó armat de cel¿les rectangulars fonamentats sobre banqueta d'escullera. Prenent el projecte original com a punt de partida, i amb l'objecte d'estudiar l'impacte econòmic en termes de cost directe que tindria un canvi d'ús de l'ampliació, el present estudi analitza una variant la qual adequarà la línia d'atracada projectada originàriament a unes noves condicions funcionals relatives a l'ús comercial de contenidors mantenint la tipologia estructural del moll i la distribució de les alineacions d'atracada. En l'estudi també s'escomet l'optimització de l'estructura del projecte original tenint en compte tant les noves accions de l'ús previst com els equips actuals d'execució de calaixos flotants, modificant per això les característiques geomètriques dels calaixos amb l'objectiu de reduir els costos directes i indirectes del projecte., [ES] Con el objeto de mejorar la operatividad y los niveles de servicio a buques comerciales de pasajeros del actual Muelle de Poniente del Puerto de Palma, la Autoridad Portuaria de Baleares ha proyectado una prolongación de la línea de atraque actual con la correspondiente ampliación de explanada adyacente. El perímetro de la explanada proyectada está conformada por cajones flotantes de hormigón armado de celdas rectangulares cimentados sobre banqueta de escollera. Tomando el proyecto original como punto de partida, y con el objeto de estudiar el impacto económico en términos de coste directo que tendría un cambio de uso de la ampliación, el presente estudio analiza una variante la cual adecuará la línea de atraque proyectada originariamente a unas nuevas condiciones funcionales relativas al uso comercial de contenedores manteniendo la tipología estructural del muelle y la distribución de las alineaciones de atraque. En el estudio también se acomete la optimización de la estructura del proyecto original teniendo en cuenta tanto las nuevas acciones del uso previsto como los equipos actuales de ejecución de cajones flotantes, modificando para ello las características geométricas de los cajones con el objetivo de reducir los costes directos e indirectos del proyecto.

[EN] In order to improve the operationality and the serviceability levels of passenger ships at the current Poniente's wharf of the Port of Palma, the Port Authority of the Balearic Islands has designed an extension of the berth and the outer yard. The perimeter of the intended outer yard is surrounded by reinforced concrete floating caissons placed on a rockfill berm foundation. Using the original design as a starting point, the purpose of this study is to analyze the economic impact in terms of direct costs resulting from an alternative proposal where the use of the wharf changes. Thus, the study will evaluate the commercial use of container ships keeping the same structural typology of the wharf and the location of the berth. Once the proper actions in the design are set, the study will also undertake a structural optimization and geometrical adjustments. The current technological developments in terms of the construction process of floating caissons will be considered so as to decrease both the direct and indirect costs of the project., [CA] Amb l'objecte de millorar l'operativitat i els nivells de servei a bucs comercials de passatgers de l'actual Moll de Ponent del Port de Palma, l'Autoritat Portuària de Balears ha projectat una prolongació de la línia d'atracada amb la corresponent ampliació d'esplanada adjacent. El perímetre de l'esplanada projectada està conformada per calaixos flotants de formigó armat de cel¿les rectangulars fonamentats sobre banqueta d'escullera. Prenent el projecte original com a punt de partida, i amb l'objecte d'estudiar l'impacte econòmic en termes de cost directe que tindria un canvi d'ús de l'ampliació, el present estudi analitza una variant la qual adequarà la línia d'atracada projectada originàriament a unes noves condicions funcionals relatives a l'ús comercial de contenidors mantenint la tipologia estructural del moll i la distribució de les alineacions d'atracada. En l'estudi també s'escomet l'optimització de l'estructura del projecte original tenint en compte tant les noves accions de l'ús previst com els equips actuals d'execució de calaixos flotants, modificant per això les característiques geomètriques dels calaixos amb l'objectiu de reduir els costos directes i indirectes del projecte., [ES] Con el objeto de mejorar la operatividad y los niveles de servicio a buques comerciales de pasajeros del actual Muelle de Poniente del Puerto de Palma, la Autoridad Portuaria de Baleares ha proyectado una prolongación de la línea de atraque actual con la correspondiente ampliación de explanada adyacente. El perímetro de la explanada proyectada está conformada por cajones flotantes de hormigón armado de celdas rectangulares cimentados sobre banqueta de escollera. Tomando el proyecto original como punto de partida, y con el objeto de estudiar el impacto económico en términos de coste directo que tendría un cambio de uso de la ampliación, el presente estudio analiza una variante la cual adecuará la línea de atraque proyectada originariamente a unas nuevas condiciones funcionales relativas al uso comercial de contenedores manteniendo la tipología estructural del muelle y la distribución de las alineaciones de atraque. En el estudio también se acomete la optimización de la estructura del proyecto original teniendo en cuenta tanto las nuevas acciones del uso previsto como los equipos actuales de ejecución de cajones flotantes, modificando para ello las características geométricas de los cajones con el objetivo de reducir los costes directos e indirectos del proyecto.

The use of aluminium alloy members in building construction has increased worldwide in recent years, especially in areas with adverse conditions such as severe industrial and marine environments. Aluminium members can be used in the structural systems of residential, industrial and commercial buildings as purlins, floor joists, rafters, decks and wall studs. corrosion resistance, lightweight nature and high strength-to-weight ratio are some of the important advantages of aluminium members. Despite of these advantages, the elastic modulus of aluminium is only one-third that of steel, making aluminium members highly susceptible to various failure modes including bearing failure. This bearing failure, commonly known as web crippling, is one of the critical failure modes of thin-walled members including lipped channel sections that are unstiffened against flexural loads. To date, only a limited amount of research studies has been conducted to investigate the web crippling failure phenomenon for aluminium structural members, and no research has been carried out on the web crippling behaviour of roll-formed aluminium lipped channel sections. Hence, this research aims to conduct an experimental study using the new American Iron and Steel Institute (AISI) S909 test procedures and associated numerical studies for lipped channel sections under four loading conditions: End-Two- Flange (ETF), Interior-Two-Flange (ITF), End-One-Flange (EOF) and Interior-One- Flange (IOF). This research also considers both unfastened (flanges not connected to the support) and fastened (flanges connected to the support) conditions to cover all possible restrain scenarios in the real-world applications. Following extensive experimental tests, a series of finite element analyses (FEA) were performed to develop precise numerical models of all the tested aluminium lipped channel sections. The general-purpose software ABAQUS, with quasi-static explicit solver, was employed for this study since contact, Thesis (PhD Doctorate), Doctor of Philosophy (PhD), School of Eng & Built Env, Science, Environment, Engineering and Technology, Full Text

[EN] In order to improve the operationality and the serviceability levels of passenger ships at the current Poniente's wharf of the Port of Palma, the Port Authority of the Balearic Islands has designed an extension of the berth and the outer yard. The perimeter of the intended outer yard is surrounded by reinforced concrete floating caissons placed on a rockfill berm foundation. Using the original design as a starting point, the purpose of this study is to analyze the economic impact in terms of direct costs resulting from an alternative proposal where the use of the wharf changes. Thus, the study will evaluate the commercial use of container ships keeping the same structural typology of the wharf and the location of the berth. Once the proper actions in the design are set, the study will also undertake a structural optimization and geometrical adjustments. The current technological developments in terms of the construction process of floating caissons will be considered so as to decrease both the direct and indirect costs of the project., [CA] Amb l'objecte de millorar l'operativitat i els nivells de servei a bucs comercials de passatgers de l'actual Moll de Ponent del Port de Palma, l'Autoritat Portuària de Balears ha projectat una prolongació de la línia d'atracada amb la corresponent ampliació d'esplanada adjacent. El perímetre de l'esplanada projectada està conformada per calaixos flotants de formigó armat de cel¿les rectangulars fonamentats sobre banqueta d'escullera. Prenent el projecte original com a punt de partida, i amb l'objecte d'estudiar l'impacte econòmic en termes de cost directe que tindria un canvi d'ús de l'ampliació, el present estudi analitza una variant la qual adequarà la línia d'atracada projectada originàriament a unes noves condicions funcionals relatives a l'ús comercial de contenidors mantenint la tipologia estructural del moll i la distribució de les alineacions d'atracada. En l'estudi també s'escomet l'optimització de l'estructura del projecte original tenint en compte tant les noves accions de l'ús previst com els equips actuals d'execució de calaixos flotants, modificant per això les característiques geomètriques dels calaixos amb l'objectiu de reduir els costos directes i indirectes del projecte., [ES] Con el objeto de mejorar la operatividad y los niveles de servicio a buques comerciales de pasajeros del actual Muelle de Poniente del Puerto de Palma, la Autoridad Portuaria de Baleares ha proyectado una prolongación de la línea de atraque actual con la correspondiente ampliación de explanada adyacente. El perímetro de la explanada proyectada está conformada por cajones flotantes de hormigón armado de celdas rectangulares cimentados sobre banqueta de escollera. Tomando el proyecto original como punto de partida, y con el objeto de estudiar el impacto económico en términos de coste directo que tendría un cambio de uso de la ampliación, el presente estudio analiza una variante la cual adecuará la línea de atraque proyectada originariamente a unas nuevas condiciones funcionales relativas al uso comercial de contenedores manteniendo la tipología estructural del muelle y la distribución de las alineaciones de atraque. En el estudio también se acomete la optimización de la estructura del proyecto original teniendo en cuenta tanto las nuevas acciones del uso previsto como los equipos actuales de ejecución de cajones flotantes, modificando para ello las características geométricas de los cajones con el objetivo de reducir los costes directos e indirectos del proyecto.

[EN] In order to improve the operationality and the serviceability levels of passenger ships at the current Poniente's wharf of the Port of Palma, the Port Authority of the Balearic Islands has designed an extension of the berth and the outer yard. The perimeter of the intended outer yard is surrounded by reinforced concrete floating caissons placed on a rockfill berm foundation. Using the original design as a starting point, the purpose of this study is to analyze the economic impact in terms of direct costs resulting from an alternative proposal where the use of the wharf changes. Thus, the study will evaluate the commercial use of container ships keeping the same structural typology of the wharf and the location of the berth. Once the proper actions in the design are set, the study will also undertake a structural optimization and geometrical adjustments. The current technological developments in terms of the construction process of floating caissons will be considered so as to decrease both the direct and indirect costs of the project., [CA] Amb l'objecte de millorar l'operativitat i els nivells de servei a bucs comercials de passatgers de l'actual Moll de Ponent del Port de Palma, l'Autoritat Portuària de Balears ha projectat una prolongació de la línia d'atracada amb la corresponent ampliació d'esplanada adjacent. El perímetre de l'esplanada projectada està conformada per calaixos flotants de formigó armat de cel¿les rectangulars fonamentats sobre banqueta d'escullera. Prenent el projecte original com a punt de partida, i amb l'objecte d'estudiar l'impacte econòmic en termes de cost directe que tindria un canvi d'ús de l'ampliació, el present estudi analitza una variant la qual adequarà la línia d'atracada projectada originàriament a unes noves condicions funcionals relatives a l'ús comercial de contenidors mantenint la tipologia estructural del moll i la distribució de les alineacions d'atracada. En l'estudi també s'escomet l'optimització de l'estructura del projecte original tenint en compte tant les noves accions de l'ús previst com els equips actuals d'execució de calaixos flotants, modificant per això les característiques geomètriques dels calaixos amb l'objectiu de reduir els costos directes i indirectes del projecte., [ES] Con el objeto de mejorar la operatividad y los niveles de servicio a buques comerciales de pasajeros del actual Muelle de Poniente del Puerto de Palma, la Autoridad Portuaria de Baleares ha proyectado una prolongación de la línea de atraque actual con la correspondiente ampliación de explanada adyacente. El perímetro de la explanada proyectada está conformada por cajones flotantes de hormigón armado de celdas rectangulares cimentados sobre banqueta de escollera. Tomando el proyecto original como punto de partida, y con el objeto de estudiar el impacto económico en términos de coste directo que tendría un cambio de uso de la ampliación, el presente estudio analiza una variante la cual adecuará la línea de atraque proyectada originariamente a unas nuevas condiciones funcionales relativas al uso comercial de contenedores manteniendo la tipología estructural del muelle y la distribución de las alineaciones de atraque. En el estudio también se acomete la optimización de la estructura del proyecto original teniendo en cuenta tanto las nuevas acciones del uso previsto como los equipos actuales de ejecución de cajones flotantes, modificando para ello las características geométricas de los cajones con el objetivo de reducir los costes directos e indirectos del proyecto.

[no abstract]

Thrust ball bearings with extremely large size and capacity, are not standardized and could not be found in catalogues. In aim to investigate possible failure causes of thrust ball bearings in heavy machinery excavators, this paper presents stress and deformations calculation supported with FME analysis in balls-raceway interfaces because of carrying whole upper construction and allow rotation movement. In this paper it was performed numerical calculations and their comparison for two, conceptually different types of large size thrust bearings. First one is classical pivot, such as load distribution in modified new bearing solution. Contact stress calculation of those bearings and FME analysis show that stress and deformation values for ball are near to the limit of static load capacity. Presented study supported by images of balls and raceways damage appearance, with or without grease as a lubricant, could be very useful in the bearing failure analysis.

The paper contains the analysis 86 field tests and calculations conducted by the authors for predicting the safe bearing capacity of shallow foundations. Limit state design of shallow foundation is studied. The allowable plastic shear zones were estimated by elasto-plastic FE analysis.

The paper contains the analysis 86 field tests and calculations conducted by the authors for predicting the safe bearing capacity of shallow foundations. Limit state design of shallow foundation is studied. The allowable plastic shear zones were estimated by elasto-plastic FE analysis.

Premature fatigue failure is observed in rolling element bearings used in wind turbine components. It is believed that decomposed hydrogen from the lubricant diffuses into the surface of the bearing inner ring making it susceptible to failure. An attempt is made to simulate the formation of these cracks by accelerated laboratory tests. Hydrogen is artificially infused into the surface of ring specimens and the rings are then press fit onto shafts. This introduces a tensile Hoop Stress in the rings. The rings are then run against each other until fracture of one of the rings is observed. Preliminary test results show a failure characteristics similar to those observed in the inner rings of rolling element bearings used in service.

A straightforward procedure to predict bearing strength in bolted composite structures has been developed. The method is based on a finite element analysis, using structural elements, followed by a post-processing procedure. Bolt-hole clearance, friction between member plates, fastener clamp-up and fastener deformation is accounted for. Forces calculated in the FE-analysis are converted into a local stress field which is used in an existing criterion to predict fiber microbuckling in the most critically loaded lamina. Predictions were compared with experiments which validated the method. The small computational cost required by the procedure suggests that the method is applicable on large scale structures and suitable to use in conjunction with iterative schemes such as optimization and statistical investigations., QC 20130819

A straightforward procedure to predict bearing strength in bolted composite structures has been developed. The method is based on a finite element analysis, using structural elements, followed by a post-processing procedure. Bolt-hole clearance, friction between member plates, fastener clamp-up and fastener deformation is accounted for. Forces calculated in the FE-analysis are converted into a local stress field which is used in an existing criterion to predict fiber microbuckling in the most critically loaded lamina. Predictions were compared with experiments which validated the method. The small computational cost required by the procedure suggests that the method is applicable on large scale structures and suitable to use in conjunction with iterative schemes such as optimization and statistical investigations., QC 20130819

A straightforward procedure to predict bearing strength in bolted composite structures has been developed. The method is based on a finite element analysis, using structural elements, followed by a post-processing procedure. Bolt-hole clearance, friction between member plates, fastener clamp-up and fastener deformation is accounted for. Forces calculated in the FE-analysis are converted into a local stress field which is used in an existing criterion to predict fiber microbuckling in the most critically loaded lamina. Predictions were compared with experiments which validated the method. The small computational cost required by the procedure suggests that the method is applicable on large scale structures and suitable to use in conjunction with iterative schemes such as optimization and statistical investigations., QC 20130819

peer-reviewed, Single-lap, carbon-epoxy joints with countersunk fasteners were modelled using the nonlinear finite element code Abaqus. A highly-detailed analysis of the stress distribution at the countersunk hole boundary is provided. Bolt-hole clearance, which arises due to limitations in manufacturing capabilities, is modelled extensively. Clearance levels both inside and outside typical aerospace fitting tolerances are studied and the finite element model is validated with experimental data. Plots of radial stress in each ply of the countersunk laminate show the load transfer to be severely localised, with only a few plies bearing the majority of the load. The inclusion of clearance in the model was shown to result in far higher radial stresses compared to those in the neat-fit joint model. An associated loss in joint stiffness of more than 10% was recorded for the highest clearance considered (240 mu m). Finally compressive through-thickness stresses are shown to be present at the damageable region of the countersunk hole, and increase with bolt-hole clearance. These compressive stresses, which are an indicator of lateral constraint, are seen to suppress "brooming" failure in the countersunk laminate. (C) 2011 Elsevier Ltd. All rights reserved., Accepted, peer-reviewed

A straightforward procedure to predict bearing strength in bolted composite structures has been developed. The method is based on a finite element analysis, using structural elements, followed by a post-processing procedure. Bolt-hole clearance, friction between member plates, fastener clamp-up and fastener deformation is accounted for. Forces calculated in the FE-analysis are converted into a local stress field which is used in an existing criterion to predict fiber microbuckling in the most critically loaded lamina. Predictions were compared with experiments which validated the method. The small computational cost required by the procedure suggests that the method is applicable on large scale structures and suitable to use in conjunction with iterative schemes such as optimization and statistical investigations., QC 20130819

A straightforward procedure to predict bearing strength in bolted composite structures has been developed. The method is based on a finite element analysis, using structural elements, followed by a post-processing procedure. Bolt-hole clearance, friction between member plates, fastener clamp-up and fastener deformation is accounted for. Forces calculated in the FE-analysis are converted into a local stress field which is used in an existing criterion to predict fiber microbuckling in the most critically loaded lamina. Predictions were compared with experiments which validated the method. The small computational cost required by the procedure suggests that the method is applicable on large scale structures and suitable to use in conjunction with iterative schemes such as optimization and statistical investigations., QC 20130819

Bearing damage in modern inverter-fed AC drive systems is more common than in motors working with 50 or 60 Hz power supply. Fast switching transients and common mode voltage generated by a PWM inverter cause unwanted shaft voltage and resultant bearing currents. Parasitic capacitive coupling creates a path to discharge current in rotors and bearings. In order to analyze bearing current discharges and their effect on bearing damage under different conditions, calculation of the capacitive coupling between the outer and inner races is needed. During motor operation, the distances between the balls and races may change the capacitance values. Due to changing of the thickness and spatial distribution of the lubricating grease, this capacitance does not have a constant value and is known to change with speed and load. Thus, the resultant electric field between the races and balls varies with motor speed. The lubricating grease in the ball bearing cannot withstand high voltages and a short circuit through the lubricated grease can occur. At low speeds, because of gravity, balls and shaft voltage may shift down and the system (ball positions and shaft) will be asymmetric. In this study, two different asymmetric cases (asymmetric ball position, asymmetric shaft position) are analyzed and the results are compared with the symmetric case. The objective of this paper is to calculate the capacitive coupling and electric fields between the outer and inner races and the balls at different motor speeds in symmetrical and asymmetrical shaft and balls positions. The analysis is carried out using finite element simulations to determine the conditions which will increase the probability of high rates of bearing failure due to current discharges through the balls and races.

Diplomová práce se zabývá problematikou diagnostiky točivých strojů. K řešení byla využita online diagnostika společně s tvorbou vyhodnocovací aplikace v prostředí Matlab. Provedeným testováním byla získána data pro použití neuronové sítě. Výsledkem bylo určení stavu modelu pomocí uživatelské aplikace., The diploma thesis deals with the issue of diagnostic of rotating machines. Online diagnostics was used for the solution with the creation of an evaluation application in the Matlab. Through the performer testing, data was obtainde for the use of an neural network. The result was the determination of the state of the model using the user application.

Diplomová práce se zabývá problematikou diagnostiky točivých strojů. K řešení byla využita online diagnostika společně s tvorbou vyhodnocovací aplikace v prostředí Matlab. Provedeným testováním byla získána data pro použití neuronové sítě. Výsledkem bylo určení stavu modelu pomocí uživatelské aplikace., The diploma thesis deals with the issue of diagnostic of rotating machines. Online diagnostics was used for the solution with the creation of an evaluation application in the Matlab. Through the performer testing, data was obtainde for the use of an neural network. The result was the determination of the state of the model using the user application.

peer-reviewed, This thesis investigates the use of specially-designed “tension absorber” joints in composite vehicular structures for the absorption of energy in a crash situation through a process referred to here as “extended bearing failure”. The specific targeted application is future narrow-body composite aircraft fuselages which require an innovative energy absorption strategy due to the limited height available below the cargo floor for traditional crush beams. However, tension absorbers could be applied in any structure requiring energy-absorption capability in a crash or overload situation. Through a combined experimental-numerical approach, the work aims to provide fundamental information on the effects of geometric and material parameters such as stacking sequence, pin diameter, laminate thickness and loading rate, and an assessment of whether state-of-the-art numerical simulation is capable of providing genuinely predictive capability for such a complex problem. To make the results as useful as possible the chosen material is IM7/8552 carbon/epoxy, one of the most widely-characterised materials in the literature. Thus the results can be used by other researchers to test out modelling approaches without the need for further material testing. Besides the results in the published papers, videos provided as supplementary information contain complete three-dimensional (3D) maps of internal specimen damage, obtained from computed tomography (CT). The chosen performance parameters are ultimate bearing strength (UBS), mean crushing stress (MCS) and mass-specific energy absorption (SEA). Diameter-to-thickness (D/t) ratio is found to be an excellent predictor of UBS and SEA for both quasi-static and dynamic loading rates, with small D/t values giving best results, provided the thickness is sufficient to avoid global bending of the specimen. Concerning the effects of stacking sequence, it is found that the most important factor in maximising SEA is having small changes in orienta

peer-reviewed, This thesis investigates the use of specially-designed “tension absorber” joints in composite vehicular structures for the absorption of energy in a crash situation through a process referred to here as “extended bearing failure”. The specific targeted application is future narrow-body composite aircraft fuselages which require an innovative energy absorption strategy due to the limited height available below the cargo floor for traditional crush beams. However, tension absorbers could be applied in any structure requiring energy-absorption capability in a crash or overload situation. Through a combined experimental-numerical approach, the work aims to provide fundamental information on the effects of geometric and material parameters such as stacking sequence, pin diameter, laminate thickness and loading rate, and an assessment of whether state-of-the-art numerical simulation is capable of providing genuinely predictive capability for such a complex problem. To make the results as useful as possible the chosen material is IM7/8552 carbon/epoxy, one of the most widely-characterised materials in the literature. Thus the results can be used by other researchers to test out modelling approaches without the need for further material testing. Besides the results in the published papers, videos provided as supplementary information contain complete three-dimensional (3D) maps of internal specimen damage, obtained from computed tomography (CT). The chosen performance parameters are ultimate bearing strength (UBS), mean crushing stress (MCS) and mass-specific energy absorption (SEA). Diameter-to-thickness (D/t) ratio is found to be an excellent predictor of UBS and SEA for both quasi-static and dynamic loading rates, with small D/t values giving best results, provided the thickness is sufficient to avoid global bending of the specimen. Concerning the effects of stacking sequence, it is found that the most important factor in maximising SEA is having small changes in orienta

Diplomová práce se zabývá problematikou diagnostiky točivých strojů. K řešení byla využita online diagnostika společně s tvorbou vyhodnocovací aplikace v prostředí Matlab. Provedeným testováním byla získána data pro použití neuronové sítě. Výsledkem bylo určení stavu modelu pomocí uživatelské aplikace., The diploma thesis deals with the issue of diagnostic of rotating machines. Online diagnostics was used for the solution with the creation of an evaluation application in the Matlab. Through the performer testing, data was obtainde for the use of an neural network. The result was the determination of the state of the model using the user application.

Diplomová práce se zabývá problematikou diagnostiky točivých strojů. K řešení byla využita online diagnostika společně s tvorbou vyhodnocovací aplikace v prostředí Matlab. Provedeným testováním byla získána data pro použití neuronové sítě. Výsledkem bylo určení stavu modelu pomocí uživatelské aplikace., The diploma thesis deals with the issue of diagnostic of rotating machines. Online diagnostics was used for the solution with the creation of an evaluation application in the Matlab. Through the performer testing, data was obtainde for the use of an neural network. The result was the determination of the state of the model using the user application.

Diplomová práce se zabývá problematikou diagnostiky točivých strojů. K řešení byla využita online diagnostika společně s tvorbou vyhodnocovací aplikace v prostředí Matlab. Provedeným testováním byla získána data pro použití neuronové sítě. Výsledkem bylo určení stavu modelu pomocí uživatelské aplikace., The diploma thesis deals with the issue of diagnostic of rotating machines. Online diagnostics was used for the solution with the creation of an evaluation application in the Matlab. Through the performer testing, data was obtainde for the use of an neural network. The result was the determination of the state of the model using the user application.

Diplomová práce se zabývá problematikou diagnostiky točivých strojů. K řešení byla využita online diagnostika společně s tvorbou vyhodnocovací aplikace v prostředí Matlab. Provedeným testováním byla získána data pro použití neuronové sítě. Výsledkem bylo určení stavu modelu pomocí uživatelské aplikace., The diploma thesis deals with the issue of diagnostic of rotating machines. Online diagnostics was used for the solution with the creation of an evaluation application in the Matlab. Through the performer testing, data was obtainde for the use of an neural network. The result was the determination of the state of the model using the user application.