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The low heat conduction values and high mechanical properties of stainless steels, which have high resistance to corrosion, make them difficult to be machined. Custom 450, a martensitic stainless steel alloy, is highly resistant to corrosion especially at high temperatures and is used in ammunition coolant tanks. Although there are studies on the machinability of stainless steel alloys in the literature, studies on the drillability of Custom 450 martensitic stainless steel are quite limited. For this reason, Custom 450 material was subjected to drilling experiments in the study with 4 different cutting speeds and 4 different feed rates using 4 different carbide drill bits without using coolant. In order to model and minimize the thrust force, drill bit temperature and burr height values, experiments and measurements were carried out using the L16 orthogonal arrays of Taguchi method. Drilling variables were optimized simultaneously by applying Taguchi-based Grey Relational Analysis (GRA) with the help of the data obtained from the experiments. Mathematical models have been developed by using the Response Surface Method (RSM) in order to predict the experimental results. It was observed that there was a significant increase in the thrust forces and burr heights with increasing values of the feed rate. The drill bit temperature was adversely affected by the increasing values of cutting speed. According to the analysis of variance, it was seen that the most effective control factors were 86.30% feed rate for thrust force, 97.52% cutting speed for temperature and 85.87% for burr height. Following the GRA, the feed rate was found to be the most important control factor with a value of 0.2921. Moreover, according to the results of multiple response optimizations, the most suitable parameters were identified as 15 m/min. Cutting speed, 0.005 mm/rev feed rate, and the drill bit number 4. The reliability of the developed mathematical model was confirmed with determination coefficients which are 98.34% for thrust forces, 99.78% for drill bit temperature and 98.54% for burr height.

Titanium alloy Ti6Al4V, an alpha-beta alloy, possesses many advantageous properties, such as high special strength, good resilience and resistance to high temperature and corrosion, fracture resistant characteristics and so on, being widely used in aerospace, biomedical and chemical industry. However, its machinability is still a challenge due to its low thermal conductivity, low elastic modulus and high chemical reactivity. As a novel and effective machining method, ultrasonic vibration assisted machining (UVAM) can effectively improve the machining performance of workpieces, which is widely used in the field of titanium alloy machining. A two-dimensional cutting finite element modeling methodology for orthogonal cutting titanium alloy Ti6Al4V was established to analyze the comparisons between conventional machining (CM) and ultrasonic vibration assisted machining and the effects of frequency and amplitude. The simulation results showed that (1) UVAM more easily formed serrated chip than that of CM. The chip segmentation coefficient GS which could quantitatively characterize the segmentation degree of chip showed an increasing trend with the increase of amplitude. (2) The cutting force curve of UVAM had periodic pulse fluctuation due to the effects of vibration in x-direction and y-direction. The main cutting force and the thrust force of UVAM showed the further decrease trend with the increase of frequency and x-direction amplitude. However, the y-direction amplitude made the contrary trend for the cutting force. (3) Meanwhile, with the increase of y-direction amplitude, the plastic and friction dissipation energies increased obviously. The introduction of ultrasonic vibration results in complex changes in the tool-chip contact, mechanical and temperature characteristics of the workpiece. Choosing the suitable vibration parameters will contribute to improving the machinability of titanium alloys.

The CFRP/metal co-cured material which possesses the outstanding properties of both lightweight and high strength has become one of the commonly used materials in the design and manufacture of attitude control flywheel. However, few studies are reported concerning the mechanical drilling operation of this newly developed structural material. To cover the gap and enrich the scientific field of this topic, the present work was performed to specially evaluate the drilling performances of a co-cured material composed of carbon fiber reinforced plastic (CFRP) and invar alloy. The significance of the present work aims to on the one hand, reveal the evolution of vital cutting phenomena including thrust forces, cutting temperatures and surface quality of drilling holes as function of cutting parameters, and on the other hand address the mechanism of controlling the interfacial drilling response. The results indicate that both the thrust forces and cutting temperatures during drilling of the invar phase are relatively higher compared to that of the CFRP phases while it presents elevation for the lower CFRP phase than the upper one due to the effect of chip ejection. The evolution of thrust forces and drilling temperatures present common regularity, in which the feed rate and cutting speed play an essential role, respectively. It is worth noting that the hole size indicates disparities for all the involved layers regardless of the machining parameters, of which the hole size exceeds the nominal diameter for the upper CFRP phase while it presents lower magnitudes for the lower CFRP phase and close gap between the invar phase and expected value. Surface cavity and fiber pullout dominate the hole surface morphology for the upper CFRP phase, matrix degradation and micro-cracks appear on the hole wall of the lower CFRP phase, and chip adhesion and oxidation are the cases for the invar layer. The mechanical effect induces the notch and the thermal effect causes the matrix degradation, which controls the cutting response for the upper and lower interface, respectively.

DESTINY+ is a medium-class interplanetary mission, selected by the Japan Aerospace Exploration Agency for potential launch windows in the first half of 2020s. The mission will demonstrate innovativ...

A torus-shaped sail consists of a reflective membrane attached to an inflatable torus-shaped rim. The sail’s deployment from its stowed configuration is initiated by introducing inflation pressure into the toroidal rim with an attached circular flat membrane coated by heat-sensitive materials that undergo thermal desorption (TD) from a solid to a gas phase. Our study of the deployment and acceleration of the sail is split into three steps: at a particular heliocentric distance a torus-shaped sail is deployed by a gas inflated into the toroidal rim and the membrane is kept flat by the pressure of the gas; under heating by solar radiation, the membrane coat undergoes TD and the sail is accelerated via TD of coating and solar radiation pressure (SRP); when TD ends, the sail utilizes thrust only from SRP. We study the stability of the torus-shaped sail and deflection and vibration of the flat membrane due to the acceleration by TD and SRP.

High precision drilling is required to ensure the structural integrity of the aircraft. Therefore, strict quality controls are required to ensure optimum hole quality since hundreds of thousands of holes are drilled into different aircraft structures. The large number of holes required for riveting means that their installation must be carried out in a fast and precise manner. This can be achieved using multi-head drilling tools that can drill several holes simultaneously. The current study investigated the use of a multi-spindle drill head that can produce three holes simultaneously. Uncoated carbide and TiAlN-coated and TiSiN-coated carbide drills were used to assess cutting forces, hole surface roughness, burr formations and tool condition when machining Al2024 aerospace alloy under dry machining conditions. Analysis of variance was employed for estimating the relationships between the input parameters (spindle speed, feed and tool coating) and the studied hole quality metrics. Furthermore, a regression model was developed with a regression coefficient (R2) of more than 90% for the prediction of measured responses. Interestingly, better results in lower thrust force and surface roughness were obtained using the uncoated carbide drills compared with TiAlN and TiSiN, while the performance of TiAlN was found to be better than those obtained from TiSiN.

This work examines the most promising design solutions for the creation of propulsion systems for ultra-light launch vehicles by small private enterprises in the rocket and space industry. Comparison of the metal consumption of the combustion chambers with the energy characteristics at different operating pressures showed that the most optimal operating pressure is 12,16 MPa. Comparison of the relative and absolute values of the masses of various configurations describes the nature of the relationship between the number of combustion chambers and the total mass of the propulsion system. It was found that nine-chamber propulsion systems with cameras made with extensive use of additive technologies best meet the key requirements. The analysis carried out includes an assessment of the design parameters of both various components and assemblies and the propulsion system as a whole. Various layouts of propulsion systems are considered in detail, the required degree of technological complexity of structures of various units and assemblies, their production cost are estimated. The ratio of the obtained mass-energy characteristics was achieved through the implementation of design solutions that became available due to the use of additive technologies. The obtained results of preliminary calculations demonstrate the applicability and efficiency of design solutions considered for use in the propelled propulsion system for a promising launch vehicle.

Non-hazardous, toxic-free, allergic-free and less cost-orientated methods are expected by the industries and the industrial workers for the better working-environment. In this work, an effort is made to achieve this expectation by integrating the concept of surface texturing and lyophobic wettability for anti-friction and self-lubrication purpose. Turning experiments are conducted on Al 6061 T6 material using Non-Textured (NT) Poly-Crystalline Diamond (PCD) insert, Cross-Chevron Textured insert (CCT), dip and drop based lyophobic wettability solutions filled texture inserts (TDI and TDR) under dry conditions. Lyophobic wettability was formed using amino silane functionalisation on the insert surface. Cross-chevron textures are engineered on the insert's rake face using Nd: YAG laser texturing machine. The experimental results observed with the lesser main cutting force and thrust force for the dip based lyophobic wettability insert than the non-textured, cross-chevron textured and drop based lyophobic wettability inserts.

Ultrasonic assisted turning (UAT) has shown significant advantages over conventional turning (CT) due to its intermittent cutting nature. There have been some issues related to the machining responses which have not been much explored. Most of the issues are driven by the cutting force which is a function of material properties. Present article gives finite element modeling (FEM) of UAT with external heating at different temperature assuming it alters the material properties particularly in terms of material softening. The objective is to analyze the effect of temperature, vibration amplitude, frequency and cutting speed on the machining responses using two different materials SS304 and low carbon (0.08%) steel. The parameters such as feed rate, tool rake angle and nose radius are kept constant. The shear angle, cutting force, and thrust force are determined as output responses. The FEM results show a significant effect of external heating in shear angle, cutting force and thrust force for both SS304 and low carbon steel. It is observed that as the temperature increases, there is an increment in shear angle and reduction in average cutting force and average thrust force. Moreover, a significant improvement in machining forces and shear angle was also noticed at a higher value of amplitude, cutting speed and frequency.

For machining operation, it is still the challenge to understand the process and selection of cutting tool materials. The motivation for using CBN tools in reconditioning of dies and form tools after useful life which presses for studying critical issues and working for eliminating the costly grinding equipment with CNC turning machine where the job can be completed in one setup. This experimental work involved mechanical characterization of AISI D6 tool steel using low CBN tools based on various analysis; machinability behavior of the tool material and; revealing of CBN tool wear and tool wear mechanisms based on microstructural analysis using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDAX). The novel mathematical models developed are the output response parameters like thrust force, main cutting force, cutting temperature, and surface roughness w.r.t. to variation in cutting speed and feed rate. The parametric analysis study showed that the thrust force, the main cutting force increases with feed. Surface finish improved with feed and the properties and features of tool materials influenced the thrust force and cutting temperature. In case of interrupted hard turning the cutting speed does not affect the main cutting force and thrust force, whereas it has a significant effect on cutting temperature along with feed and inserts grades. Crater wear, micro-chipping, and breakages of cutting edges in continuous turning with abrasion and diffusion being predominant whereas, the worn of interrupted hard turning tools showed crater wear, while abrasion and low intense diffusion are the wear mechanisms affirmed in this study. The novelty of the work is the use of low CBN content brazed tooltips in hard turning as a solution with a low tool acquisition cost without degrading the tool performance and sacrificing productivity.

Purpose An ideal method for predicting the fatigue life of spherical thrust elastomeric bearings has not been reported, thus far. This paper aims to present a method for predicting the fatigue life of laminated rubber spherical thrust elastomeric bearings. Design/methodology/approach First, the mechanical properties of standard rubber samples were tested; the axial stiffness, cocking stiffness, torsional stiffness and fatigue life of several full-size spherical thrust elastomeric bearings were tested. Then, the stiffness results were calculated using the neo-Hookean, Mooney–Rivlin and Yoeh models. Using a modified Mooney–Rivlin constitutive model, this paper proposes an improved method for fatigue life prediction, which considers the laminated characteristics of a spherical thrust elastomeric bearing and loads of multiple multi-axle conditions. Findings The Mooney–Rivlin model could accurately describe the stiffness characteristics of the spherical thrust elastomeric bearings. A comparative analysis of experimental results shows that the model can effectively predict the life of a spherical thrust elastomeric bearing within its range of use and the prediction error is within 20%. Originality/value The fatigue parameters of elastomeric bearings under multiaxial loads were fitted and corrected using experimental data and an accurate and effective multiaxial fatigue-life prediction expression was obtained. Finally, the software was redeveloped to improve the flexibility and efficiency of modeling and calculation.

Thrust performance is one of the important indexes of permanent magnet linear synchronous motors. The traditional non-oriented silicon steel sheet is used as the core material of the permanent magnet linear synchronous motor, which limits the performance of the permanent magnet linear synchronous motors. For the oriented silicon steel sheet has a higher magnetic permeability in the rolling direction, a permanent magnet linear synchronous motor with similar number of poles and slots made of oriented silicon steel is proposed in this paper. By measuring the B-H curves of the rolling direction and the cutting direction, the thrust properties of the two motors made of traditional silicon steel sheets and oriented silicon steel sheets are analyzed and compared by the finite element method (FEM) under rated load and overload conditions respectively. The thrusts under different tooth-yoke ratios are discussed in the end.

The Beypazarı Blind Thrust Zone, which is surrounded by the North Anatolian, the Eskişehir, and the Kırıkkale-Erbaa fault zones, is a recently defined neotectonic structure developed in the NW central Anatolia together with the Eldivan-Elmadağ and the Abdüsselam Pinched Crustal Wedges. In this study, the internal structure of the Beypazarı Blind Thrust Zone has been examined in detail around Çayırhan region. It has been defined that it consists of the Karaköy, Sekli, Nalçabayırı, Uzunbayır blind thrusts, Davutoğlan Back Thrust, and Beypazarı Blind Thrust I-II from North to south, respectively with help of the fault-propagation folds in the study area. The existence of economically important and operational resources such as lignite and trona in the Neogene sequence affected by these faults in the region and earthquake generating potential of the faults determined in previous studies increase the importance of this study.

The main aim of this work is the assessment of the machinability of alloyed ductile iron before the austempering process. 16MnCr5 alloy steel and alloyed ductile specimens were subjected to drilling tests. The effect of drilling parameters on cutting force was investigated based on the Taguchi approach. Based on the results, a regression model was established to predict thrust force at various drilling conditions. The predicted thrust forces ratio was then used to evaluate the machinability of alloyed ductile respect to the 16MnCr5 alloy steel. The results showed that at lower feed rate, the normal drilling force is very close for both materials, such that the estimated machinability rating is 86%.

This paper presents a comprehensive review and analysis of ship hull cleaning technologies. Various cleaning methods and devices applied to dry-dock cleaning and underwater cleaning are introduced in detail, including rotary brushes, high-pressure and cavitation water jet technology, ultrasonic technology, and laser cleaning technology. The application of underwater robot technology in ship cleaning not only frees divers from engaging in heavy work but also creates safe and efficient industrial products. Damage to the underlying coating of the ship caused by the underwater cleaning operation can be minimized by optimizing the working process of the underwater cleaning robot. With regard to the adhesion technology mainly used in underwater robots, an overview of recent developments in permanent magnet and electromagnetic adhesion, negative pressure force adhesion, thrust force adhesion, and biologically inspired adhesion is provided. Through the analysis and comparison of current underwater robot products, this paper predicts that major changes in the application of artificial intelligence and multirobot cooperation, as well as optimization and combination of various technologies in underwater cleaning robots, could be expected to further lead to breakthroughs in developing next-generation robots for underwater cleaning.

The purpose of this study was to design a tribotester that can evaluate the lubrication performance of ferrofluids under the effect of a magnetic field. A novel bronze-based tribopair was fabricate...

The Western Black Sea basin formed during therifting of the Moesian Platform in Early Cretaceous. The closure of the Neotethys Ocean in the Middle Eocene resulted in the formation of the Pontide fold and thrust belt in northern Turkey. During this study, eight seismic reflection profiles were interpreted to determine the subsurface structural geometry and tectono-stratigraphic evolution of the offshore Akçakoca-Amasra area. The stratigraphy of the study area is determined based on a composite wireline well log of the Akçakoca-1 wildcat well, which was also used to construct a velocity model based onsonic data. We suggest that a major décollement surface was developed during the Eocene Pontide Orogeny. The decollement is located at the limestone clay-shale intraformational transition within the Late Cretaceous (Maastrichtian) - Paleocene Akveren Formation. Normal faults formed during the Cretaceous rifting in the region are located below the décollement surface. They provide tectonic ramps along the décollement surface and allow the decollement to develop ramp-flat thrust fault geometry. A well-developed duplex structure is also present along the seismic lines. The décollement surface serves as the floor thrust of the duplex structure. The roof thrust of the duplex is in the Pliocene Sarıkum formation, dominantly composed of claystone.

On a cold March night last year in Portsmouth, England, an entirely new type of aircraft flew for the first time, along a dimly lit 120-meter corridor in a cavernous building once used to build minesweepers for the Royal Navy. • This is the Phoenix, an uncrewed blimp that has no engines but propels itself forward by varying its buoyancy and its orientation. The prototype measures 15 meters in length, 10.5 meters in wingspan, and when fully loaded weighs 150 kilograms (330 pounds). It flew over the full length of the building, each flight requiring it to undulate up and down about five times.

The team of nine students from the Virginia Military Institute (VMI) collectively held their breath during the countdown. The result of their yearlong project-an 11-fttall, 60-lb rocket-stood on the launchpad, holding an autonomous soi l-col lect ing robot they had designed. There was little doubt the engines would ignite, developing 450 lbf of thrust within 200 ms; their worry was whether the robot would eject at apogee and survive the resulting 1,000-ft fall.

An elastic inhomogeneous coating is considered for which a simplified deformation model is proposed in the framework of the concept of an asymptotically thin layer. Based on such a model for an inhomogeneous coating, a solution of the contact problem in the presence of intermolecular interaction is constructed and the wear kinetics for the thrust sliding bearing is calculated. It is shown that the pattern of the inhomogeneity of the coating can have a significant effect on its stress-strain state and wear kinetics.

The structure design of an autonomous/remote underwater vehicle, Intelligence Ocean $\mathbf {I}$ (IO- $\mathbf {I}$ ), capable of operating in ROV or AUV mode and acquiring marine environment information and its own status data are outlined first in this paper. The dynamics equations of underwater vehicles in horizontal and vertical are given to describe the movement of an underwater vehicle, taking the gravity, buoyancy, thrust and hydrodynamic force into account. Furthermore, in order to realize high precision automatic control of robot, the fuzzy control algorithm which belongs to the intelligent control is combined with the cascade PID control algorithm to realize an modified underwater vehicle control algorithm, which improves the applicability of the control algorithm and reduces the difficulty and workload of parameter adjustment. The proposed control algorithm is recognized in numerical simulations as well as in experimental tests which confirm the good performance of the controller and the prototype.

The purpose was to evaluate part properties of additively manufactured 18Ni-300 maraging steel in a unified set-up when the printing orientation and the heat treatment were independently changed. Though the hardness, shrinkage, and drilling thrust force showed isotropic behavior to a certain extent, anisotropy was observed in the flatness, surface roughness, dross, and thread profiles. Solution treatment increases the surface roughness and reduces the flatness, surface hardness, drilling thrust force, and thread quality to some extent. Aging treatment significantly increases the surface hardness and yet still allows good-quality threads to be cut. The study aids designers in establishing and corroborating design for additive manufacturing.

The piston pump is the key power component in the civil aircraft hydraulic system, and the most common pump used in the aviation field is the pressure compensated variable displacement type. In this review paper, a basic introduction to the civil aircraft piston pump is presented, including the classification, structure, working principle, design features, and achievements by some research groups. Then, the future directions of the aircraft pump are reported from various perspectives. Further, the critical technologies are analyzed and summarized in detail from six thrust areas: friction couples, noise reduction, inlet boost, thermal management, fault diagnosis and health management, and mechanical seal. Finally, the challenges and limitations of the research on the aircraft pump are discussed to provide valuable insight for future scholars. Keywords: Civil aircraft, Engine driven pump, High pressure, Inlet boost, Intelligent control, Lubricating gaps, Piston pumps, Pulsation reduction

Bu çalışmada, askeri ve sivil havacılık alanındayoğun olarak kullanılmakta olan karbon fiber takviyeli polimer kompozit (CFRP)malzeme ve Al-7075 alaşımının oluşturduğu CFRP/Al-7075 istifli yapının, 120º-130º-140ºuç açılarına sahip kaplamasız karbür matkaplar ile delinebilirliğiaraştırılmıştır. Delme süreçlerinde itme kuvveti (Fz), moment (Mz),delik ortalama yüzey pürüzlülükleri (Ra), talaş yapıları ve CFRPmalzemede meydana gelen delaminasyonlar (Fd) incelenmiştir. Deneyselçalışmalar kuru kesme şartlarında 50 m/dk.. kesme hızı ve 0,05 mm/dev. sabitilerleme değerinde, doğrudan delme yönteminde gerçekleştirilmiştir. 120° ve 130° uç açılı matkaplar CFRP malzemedeyakın Fz ve Fd değerleri sergilerken, uç açılarına göreen düşük Fz, Mz, Ra ve en düşük Fdverileri sırasıyla 130°-120º-140º uç açılı matkaplarda elde edilmiştir. 140° uçaçılı matkapta, esas kesici kenarda yoğun miktarda çapaklanma ve yığıntı talaş(Built up edge BUE) meydana gelmiş ayrıca matkap helis kanallarında Al talaşlarısıvanmıştır. Deneysel çalışmaların ardından matkap uç açılarının itme kuvveti (Fz)ve ortalama yüzey pürüzlülüğü (Ra) üzerine etkileri %95 güvenaralığında ANOVA ile belirlenmiş ve çoklu karşılaştırma testleri uygulanmıştır.Sonuç olarak, 130º uç açılı kaplamasız karbür matkabın moment, itme kuvveti, ortalamayüzey pürüzlülüğü ve delaminasyon bakımından belirtilen kesme parametreleri vedelme koşulları doğrultusunda CFRP/Al-7075 istifli delme işleminde daha iyisonuçlar verdiği görülmüştür., In this study, thedrillability of CFRP/Al-7075 stacked structure which is formed by carbon fiberreinforced polymer composite (CFRP) material, which is used intensively in thefield of military and civil aviation, and Al-7075 alloy has been investigatedby drilling with uncoated carbide drills with different point angles. In thedrilling processes thrust force (Fz), moment (Mz), holeaverage surface roughness (Ra), chip structure and delamination (Fd)occurring in CFRP material were investigated. Experimental studies wereperformed under dry cutting conditions with 50 m/min cutting speed and 0.05 mm/revconstant feed rate by using three different drill (120º-130º-140º) point anglesuncoated carbide drills. 120° and 130° point angle drills are showed close Fzand Fd values in the CFRP material, while the lowest Fz, Mz,Ra and lowest Fd value are obtained respectively in130°-120º-140º point angle drills. In the 140° point angle drill, a largeamount of burring and built-up edge (BUE) was formed on the main cutting edgeand Al chips were plastered in the drill helix flutes. After experimental studies,the effects of drill point angles on thrust force and average surface roughnesswere determined by ANOVA at 95% confidence interval and multiple comparisontests were applied. As a result, it has been seen that 130º point angleuncoated carbide drill gives better results in terms of moment, thrust force,average surface roughness and delamination, under specified cutting parametersand drilling conditions in CFRP/Al-7075 stacking drilling.

Ultra-precision tool-servo-based diamond cutting (UTSDC) is a promising technology for fabricating true 3-dimensional optical microstructures. The diamond tool in UTSDC moves alternatively upward and downward along the thrust direction. However, most studies on the material removal mechanism are limited to the orthogonal cutting condition where the depth of cut is invariant. The effect caused by the tool motion in the thrust direction has been overlooked. In this paper, the indentation effect affected by the tool path, tool shape and cutting speed is systematically studied. It is found that the inclined angle between the tool path direction and the main cutting direction plays a key role in the determination of the material spring back and the formation of side burr. The characteristics of indentation force and material spring back indicates that the indentation mechanism is dominant in the cut-in process where the inclined angle is large, while the shearing mechanism is dominant in the cut-out process. A new theory is proposed to explain the tool indentation mechanism in UTSDC, and the simulation results show that the theory can well predict the indentation force under various cutting conditions.

Drilling process plays a vital role in the development of polymer clay nanocomposites. The effects of various parameters, such as tool, feed rate and speed to generate the impact on tangential force, thrust force and delamination factor acting on the material in production are studied during drilling operations in the aerospace and automotive industries. The input variable settings to adjust the speed and feed rate to show the outcomes of tangential force, thrust force and delamination factor of the material according to the consumption of the parts in the next stage of manufacturing are calculated by efficient feed rate optimization. A series of tests are performed by changing tools such as High speed steel (HSS), end mill (HEM), High speed steel (HSS), twist drill (HTD) and carbide twist drill (CTD) on various materials to evaluate the influence on the feed rate and speed. Based on the experimental analysis, mathematical modeling is implemented to study the properties of glass fiber reinforced polyester nanocomposite (GFRPNC; 3[Formula: see text]wt.%). Using the desirability approach, the optimum operating conditions of the selected process variables are considered to minimize delamination. A full factorial experiment design is adopted using the two fundamental concepts of replication and randomization of experimental design to research the relationship between the variables. Based on the analysis of variance (ANOVA), the process model is formulated using the [Formula: see text] statistical kit. It is inferred that the delamination factor is minimal for all tools (CTD, HTD and HEM) at 0.1[Formula: see text]mm/rev feed rate and speed at 852[Formula: see text]rpm.

The development of experimental propulsion projects by undergraduate students introduces new practical knowledge to improve competitiveness in the rocket industry. This work addresses a methodology for testing solid engines based on an embedded and mechanical system at low cost from the modeling of the solid potassium nitrate propellant with candy-rocket sucrose propellant (KNSB). The purpose of this study was modeling of the rocket engine, the design and manufacture of the test bench and the design of the Integrated system to measure the thrust of the rocket engine. Complementarily, the result of an experimental measurement is detailed and compared with the analytical study of the thrust. Using small rockets to study atmospheric precipitation requires several engine tests. For this reason, it is important to study different engines for the academic missions that are proposed in the future. The Universidad Nacional de Ingenieria promotes this research that also participates in the “CSPACE” launch campaigns organized by the French Space Agency in Tarbes, France and won the Technological Innovation Award from the Peruvian Oil and Energy Mining Society in 2018.

Artillery weapons based on electromagnetic launchers such as linear induction motor guns, railguns and coil-guns are being pursued as an alternative to conventional chemical-driven weapons due to their superior performance both in terms of range and destructive power. This paper presents a comparative analysis of linear induction motor guns versus coil-guns. The analysis is carried out in MATLAB/SIMULINK environment. An attempt has been made to identify technology which is better suited for carrying out artillery warfare. The mechanical performances such as muzzle velocity of projectiles, acceleration and thrust on the projectiles are analysed to make an appropriate conclusion for on-field deployability of each of these weapons.

Remotely Operated Underwater Vehicles (ROV) currently have been utilized for scientific and commercial applications. Many industries are involved in developing robots in order to reduce human effort as well as increase productivity, efficiency, and monitoring. That said, the need to optimize the cost for design of ROVs became popular. In the present work, a simplified design procedure of a low cost-light-weight ROV is proposed. The design overview includes a description of the three thrusters operated by bilge pump electric motors. The ROV contains only a camera, an IMU and a GPS sensor. The ROV is wired to a control station that is equipped with a screen with a GUI, a joystick and a keyboard to monitor and control the ROV. The design is optimized to achieve a neutral buoyancy force in order to reduce the stabilizing effort during operation, hence reducing energy consumption. The drag force, lift force, drag center, lift center and fluid velocity contours are predicted using a CFD tool. Dynamic analysis including thrust and drag forces in longitudinal, vertical and yaw directions of motion are investigated to facilitate selection of the prime movers. Finally, the control strategy and electrical system description is presented. The proposed methodology proved that a satisfactory performance with an optimized design is achievable. The ROV design presented could be used in quick and low cost inspection of ships.

This paper presents a novel structure of the permanent magnet linear synchronous motors (PMLSMs). Using oriented silicon steel sheet (OSSS) instead of traditional non-oriented silicon steel sheet (NOSSS) as the mover of the proposed PMLSM. The OSSS possess better magnetic permeability and anti-saturation ability than NOSSS in the rolling direction, so setting the rolling direction is consistent with the magnetic circuit directions of the tooth. By the analysis thrust and saturation effect and employed the finite element software, the results display that the use of OSSS as the mover core material can increase the electromagnetic thrust and overload capacity.

For design of marine propeller, the energy supply from marine engine to the propeller should be converted to thrust force with minimum losses. Furthermore, the unwanted vibration and cavitation due to the overlooking a detail calculation of the propeller should be prohibited for increasing the fuel efficiency and life-span of the propeller. In the last few decades, most of small and medium sized enterprises (SMEs) focusing their work on ship component industry in Central Java Province Indonesia provide the marine propeller to the ship manufacturer and ship repairmen in some shipyards in northern part of Central Java port. The design of the propeller is never been observed and optimized. The aim of the present work is to redesign the installed propeller on a wooden fishing boat with the new optimized design using B-Series propeller theory approach. The reverse engineering method uses three-dimensional scanner to obtain the geometrical data of the installed ship propeller. The new optimized propeller design is obtained from free software calculation based on the boat and engine specification. The comparison shows that the new optimized propeller design has a wider blade and larger pitch and increases 20% of the open water efficiency of the propeller performance at lower engine rotation. Keywords: B-series design, fishing boat, marine propeller, redesign, optimization

To understand the working principle of ornithopters, various surveys were made on the natural flyers with flapping wings and their ability to produce lift and thrust. The crank mechanism is...

Basalt is one of the potential hard rock targets for drilling sampling in asteroid exploration, and low sampling reaction forces are required in drilling sampling activities of an asteroid. In this paper, the experimental study of drilling basalt with small diameter cemented carbide triangular bit and diamond trepanning drill was carried out, and the drilling thrust force models of basalt drilled by cemented carbide triangular bit and diamond trepanning drill were established, respectively. The ratio of volume removal rate to drilling thrust force was proposed as the evaluation index for the primary selection of drilling tools. The test results showed that the Φ4 mm cemented carbide triangular bit was the preferred small diameter tool for drilling basalt when the minimum drilling thrust force is 40 N. The Φ8 mm electroplated diamond trepanning drill was also the preferred small diameter tool for drilling basalt, Its minimum critical drilling thrust is between 100 and 110 N. Further analysis of the drilling thrust model of the two types of drilling tools showed that the drilling thrust force of cemented carbide triangular bit drilling basalt increased with the feed rate, and it increased with the increase of the apex angle of cemented carbide triangular bit. There was minimum and maximum critical drilling thrust force in drilling basalt with diamond trepanning drill. When the drilling thrust force was between the minimum and maximum critical drilling thrust force, the volume removal rate can be improved by increasing the rotating speed of the diamond trepanning drill. This experimental study helps to optimize the drilling tools and set the drilling thrust force and rotating speed when further studying of hard rock sampling for asteroid drilling.

Modern industry faces a great challenge: the production of consumer goods based on a triangle comprising low costs, low production time and high quality. The optimisation of modern manufacturing processes should seek not only the reduction of manufacturing time but also the reduction of mineral resources and electric energy consumption. In the context of metalworking, considering tapping processes, studies on the use of minimum quantity of lubricant are minimal and scarce. Hence, this study deals with the application of minimum quantity of lubricant and emulsion to the processes of form and machine tapping. To this end, 7075-T651 aluminium alloy workpieces were threaded using both tapping processes at three cutting/forming speeds. M10 threads with a pitch of 1.5 mm were considered the standard profile. Torque and thrust force were monitored, and three threading heads were employed in the experimental tapping tests. According to the results, it can be concluded that the best option was to use minimum quantity of lubricant in order to reduce environmental impact, given its efficient disposal of fluids and compatibility with Softsynchro threading heads, which kept both torque and axial force close to the mean values. Furthermore, this threading head model was also the best for reducing the manufacturing time of the threads.

The objective of this work is to evaluate the performance of straight fluted HSS machine taps with 2 microns and 4 microns thickness of TiAlN coating on tapping of Al6061/SiC metal matrix composite. The methodology includes the fabrication of Al6061/SiC Metal matrix composite by stir casting process with 5, 7.5 and 10 weight percent SiC particles. Tapping operation was performed under dry conditions with different cutting speed and constant feed rate equal to the pitch of the thread. The specimens were drilled and tapped with HSS M8X1.25 machine taps coated with TiAlN coating of 2 and 4 micron thickness, in a CNC vertical machining center. The performance of HSS machine taps was evaluated in terms of tapping torque, tool flank wear, and quality of threads produced. Torque and thrust were measured using a drill tool dynamometer of Kistler make. Quality of threaded holes was analyzed by capturing the thread profile using a metallurgical microscope. The estimation of progressive flank wear of HSS machine taps was done using the profile projector. Increase in weight percentage of SiC particles and tapping speed would increase the torque required for tapping, rate of flank wear of the tool and decrease the quality of threaded holes. The progressive flank wear was found higher in machine taps with 2 microns thickness of TiAlN coating when compared to taps with 4 microns thickness of TiAlN coating. Influence of cutting speed on progressive flank wear of HSS machine tap was found to be higher compared to the thickness of TiAlN coating on the tap and weight percentage of SiC.

A cylinder liner is defined as a cylindrical part that is fitted inside the engine block to form a cylinder. It is a vital component of cylindrical engine. The most important functions of cylinder liner are to form a sliding surface for the piston to obtain a smoothly reciprocating motion, resist the wear form the piston and piston rings and sustain high pressure and high temperature. However, continuous exposure to high thermal stress, mechanical stress and friction inside combustion chamber may cause failure and reduce cylinder liner life cycle. Therefore, the main objective of this research is to study the stresses due to action of gas pressure, major thrust force of the piston, and thermal load in wet cylinder liner of Perkins 1306 diesel engine as a real case. Two materials namely cast iron, grades C4 28-48 and cast alloy steel, C4 35-56, grade 38XMIOA with three different thicknesses (t1= 13.13, t2= 9.2 and t3= 6.93) mm are considered. The finite element package ANSYS (19.1) has been used as a numerical method to calculate the stresses and deflection in 3D liner model for the three parts of cylinder sleeve. The PTC MATHCAD 4 is used to formulate the analytical solution of the selected case and the results are compared to the numerical results obtained from ANSYS. The numerical results show that the maximum deflection occurs at a point of applied piston load in which it is 0.135 mm for cast iron and 0.109 mm for steel. The deflection in circumferential is very small varied in range (-0.9 to 0.9) % of maximum deflection, and the maximum axial deflection for cast iron and steel are 0.66 mm and 0.67 mm, respectively. In addition, confirming the reliability of developed PTC MATHCAD 4 program by consider one verification case. These results show that a good agreement between the numerical and analytical methods.