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This paper would focus on the structure of aluminium alloy spot welded crash box with the trigger mechanism as the structure are widely studied for its crashworthiness as well as the location of the structure itself at the car chassis which are subjected to dynamic loading of the car. Aluminium alloy is broadly used in the car body-in-white due to the properties of sufficient strength, better formability, light weight as well as good crashworthiness properties while welded joints are also extensively used as a joining of car components. As this study use both approach of finite element and experimental, in order to validate the finite element analysis (FEA) data, it would be correlated with the experimental approach and further optimization of the finite element (FE) modelling would be made to reduce the discrepancies of data. In this study, the model updating method which update the most sensitive modal parameters would be used towards the crashworthiness analysis to observe for any significant difference with the initial crashworthiness analysis. Finite element modal analysis would be done for the crash box structure and the data would then be correlated with experiment modal analysis (EMA). The same finite element modelling would also be used for the finite element crashworthiness analysis. For modal analysis of both approach, model updating was done to reduce the discrepancies and the sensitive modal parameters were identified and it were used in the new crashworthiness analysis. From the study, it could be observed that the crashworthiness output of the crash box structure with the updated model were different from the initial crashworthiness output in term of its total energy absorbed. [ABSTRACT FROM AUTHOR]

A Spur gear drive is a mechanical drive which transmits power through toothed wheels between two parallel shafts. Spur gear teethes are parallel to the axis of the shaft, due to which while transmitting the power high impact load is acting on the gear teeth repeatedly. Fatigue analysis of spur gear drive is very important to understand the effect of repeatedly acting impact loads. In this paper, vibration fatigue analysis of two different spur gear drives with different power outputs has been performed. Spur gear drive systems are designed according to Hertz and Belayev gear design approach and finite element model is developed in ANSYS 18.1. Frequency domain approach is implemented in vibration fatigue analysis for the estimation of fatigue life by using Steinberg's three band theory and Miner's cumulative damage theory. During the vibration fatigue analysis of the systems, a constant damping ratio was used. Spur gear drive system is subjected to random loading and power spectral density is implemented for estimating the mean stresses developed in the system. Fatigue life estimation of the spur gear drive system is done for different materials: Structural steel, C45 cast steel, woven carbon epoxy prepreg and compared their fatigue life. It has been observed that C45 cast steel is the best material irrespective of the power output of the spur gear drive system. It has also been noted that for high power gear drive applications, woven carbon epoxy prepreg is more suitable than structural steel and C45 cast steel. [ABSTRACT FROM AUTHOR]

This paper study deals with selection of different material used for construction of Liquified Petroleum Gas cylinder which is used in our day-to-day life. Solidwork-2020 is used for modelling of LPG Cylinder. finite element analysis (FEA) of LPG cylinders made of Low carbon Steel and E-Glass Epoxy composites has been carried out. They are subjected to internal pressure. ANSYS (version 2021) has been used to Analyze the LPG cylinder. Both Static structural Analysis and Dynamic analysis is done. The Ansys results of deformation and stresses for Low Carbon steel & composite cylinders are compared which are built of Low carbon steel (LCS) and E-Glass Epoxy are studied. [ABSTRACT FROM AUTHOR]

Numerous empirical and numerical studies have been carried out on the mechanical characterization of ductile materials. The application of digital image correlation (DIC) equipped with three-dimensional measurement analysis was used to examine the mechanical characteristics of aluminum alloy (AL 7075). Then, the DIC outcome with finite element simulation results will be compared with the experimental results to measure the performance of the DIC. A tensile specimen of AL 7075 is tested under constant loading with a 2 mm/min displacement rate until fracture. Strain gauge and extensometer are used along with DIC monitoring technique to capture the structural deformation of the specimens. The specimen and test are simulated in ABAQUS software, in which the results are compared with experiment and DIC data, indicating a good correlation between the results. Limited data in the form of average deformation and strain of the experiments are not applicable to the plastic and necking process. In this respect, the 3D DIC results are used to analyze the strain field throughout the test, including specimen necking, and predict fracture location. Moreover, the outcome of DIC and finite element simulation are employed to examine the characteristics of AL 7075 about the large plastic deformation and mechanical behavior. The proposed 3D DIC methodology in providing insight into the characteristic mechanical behavior of ductile materials is highlighted in this paper. [ABSTRACT FROM AUTHOR]

In order to improve the reliability and load carrying capacity of composite laminates structures which were lap jointed by bolt, in this paper, the failure strength and failure mode of laminated composite pinned-joints is investigated. To determine the effects of joint geometry and stacking sequence on the bearing strength and damage mode, the multiscale numerical model combining with the Generalized Method of Cells (GMC) and considering the failure and the damage of constituent materials was created based on the ABAQUS and its user subroutine (USDFLD). A threedimensional finite element technique was used for the stress analysis. Based on the three-dimensional state of stress of each element, different failure modes were detected by the failure theories of constituent materials, all of which are applied at the fiber, matrix and fiber-matrix interface constituent level. Numerical simulations have been carried out by which edge distance-to-hole diameter ratio, and plate width-to-hole diameter ratio are varied, The composite laminated plates are stacked with the following four different orientations: [+45/-45]2s, [90/+45/-45]s, and [0/90/0]s, the results show that failure mode and bearing strength are closely related to by stacking sequence of plates and geometrical parameters. Finally, the ultimate strength and failure modes of composite bolted joints in static tension double-shear loading conditions are predicted by using the progressive damage method established and the effects of layup and dimension of laminates on the properties of the connection structure were researched in this paper. An excellent agreement is found between data obtained from this study and the experiment. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of natural convection in H-Form cavity with differentially heated side walls having two circular adiabatic obstacles. To achieve accurate solutions of the equations system defining this study, the computational methods are founded on the finite element method (FEM). Numerical illustrations have been carried out and discussed for several Rayleigh numbers from 10 to 106. We show the impact of Rayleigh number as a crucial parameter on both the heat transfer and the fluid flow. We deduce an important finding with H-Form cavity, the Rayleigh number hasn't a strong effect on both the characteristics of the fluid flow and the temperature distribution for the values ranging from 10 to 104, unlike the case of square cavity. However, its effect starts to appear from Ra = 105. The achieved results are discussed and compared with preceding works in the literature to show their effectiveness. [ABSTRACT FROM AUTHOR]

Paper presents analysis of sensitivity of parameters of Jiles-Atherton model determined during the optimization process. Recently implemented, differential evolution based method together with two-step optimization process proved, that parameters of Jiles-Atherton model can be determined in reasonable time. However, paper indicates, that in the case of isotropic materials, Bloch domain wall interaction coefficient α has too insignificant influence on the shape of hysteresis loop to be determined during the optimization. As a result, for fundamental physics analyses, α should be estimated on the base of physical properties of magnetic material. [ABSTRACT FROM AUTHOR]

The focus of the present paper is to develop a fundamental understanding of the heat conduction process in single-walled carbon nanotubes and to elucidate the contribution of the various factors which affect it at the nanometer level. As the sizes of electronic and mechanical devices are decreased to the micron and nanometer level, it becomes particularly important to predict the thermal transport properties of the components. The heat conduction in finite length SWNTs was simulated by the finite element method. Temperature at each end of an SWNT was controlled in the simulation, and the thermal conductivity was calculated from the measured temperature gradient and heat flow value. The thermal conductivity was measured for (10, 10) SWNTs with various lengths from 40 through 80 nm. The measured thermal conductivity for smaller diameter (10, 10) nanotube did not converge to a finite value with increase in tube length but obeyed a striking power law relation. The thermal conductivity of several single-wall carbon nanotubes has been calculated over a temperature range of 100-500 K using finite element method. In all cases, starting from similar values at 100 K, the thermal conductivities show a peaking behavior. The output result (Thermal Conductivity) varied from 1000 to 5266 w/m-k. The simulation results are quite similar with the results that are obtained by molecular dynamics simulation and photon spectrum analysis. We have also simulated the effect of defects in our SWNT structure. In the paper the difference of thermal conductivity between a defective and non-defective SWNT is also being discussed. More detailed analysis can be done to understand the defect influence on the thermal conductivity of carbon nanotube. The specific heat is a function of temperature [1]. We used 700 J/kg-k here as our average temperature is 300k. So, in future we hope there will be these corrections to determine the more accurate conductivity. [ABSTRACT FROM AUTHOR]

The paper discusses a modern implementation of one of approaches for numerical modelling of structure-subsoil interaction problem. A method based on incorporation of the Boussinesq solution into the finite element method procedure is shown and it's use is compared with a 3D halfspace-based solution. [ABSTRACT FROM AUTHOR]

This paper presents a new method to improve 110kV porcelain insulator flashover voltage by adding a metal ring on the insulator cap, which can not only effectively reduce the field strength of the steel cap, but also reduce the tangential field intensity of the umbrella group and inhibit the development of the discharge process, thus the flashover voltage can be increased. The surface strength calculation model of 110kV porcelain insulator is established by the finite element method (FEM), and the parameters of the metal ring are designed by neural network genetic algorithm (BP-GA). Then the experiments were carried out to verify the results, and the results show that the metal ring plate under the optimum parameters can greatly improve the flashover voltage. [ABSTRACT FROM AUTHOR]

The weighting finite element method (WFEM) is constructed to find an approximate solution to boundary value problems with a corner singularity. WFEM allows you to find a solution without loss of accuracy. This method includes three control parameters on the values of which the accuracy of finding a solution depends. This paper proposes an approach to determining the set of the optimal parameters for the weighting finite element method for the crack problem. [ABSTRACT FROM AUTHOR]

The paper considers the problem of bending a multilayer composite plate consisting of layers of unidirectional composites reinforced with thin rigid threads. It is assumed that Kirchhoff's hypotheses are fulfilled and there is a neutral surface in the domain of the plate, in which there are no deformations. Using the Lagrange variational principle, the bending equation is obtained to generalize the Sophie-Germain equation. The elastic energy functional is obtained, taking into account the different resistance of the material to tension and compression. The contact problem of bending a plate with a rigid stamp has been solved. A Lagrangian is constructed for solving an optimization problem with an inequality constraint. The Lagrangian saddle point is found using Uzawa's algorithm. A simple iteration method and a finite element method with Bell's triangular element were used to implement the Uzawa algorithm. The results of calculations of the bending of rectangular laminated plates with different directions of fiber placement and different stamp shape are presented. [ABSTRACT FROM AUTHOR]

This research is on the practice of concrete encased steel composite column associated with angle steel. This paper consists of the numerical investigation of the concrete encased four-equal-leg-angle steel column for different parameters. It is a fully encased composite column. There are total ten specimens subjected to study, containing nine 4-equal-leg angled composite column and one I-section for comparison purpose. Thirteen specimens are divided into three different sets based on the three different parameters. Parametric study was conducted to investigate the effects of different cross section, different number of steel hooping plate and height of column on the strength of the composite columns. In ABAQUS 6.14, nonlinear 3-D finite element models were generated for studies1. Load-displacement curves of different set of specimen are taken from the ABAQUS software. Stiffness is calculated from the load-displacement curve, later the result values of specimens in same set are compared and lead to the final results. [ABSTRACT FROM AUTHOR]

This paper presents numerical investigations of the texture effect on deformation-induced surface roughening in surface-modified titanium specimens subjected to uniaxial tension. Three-dimensional polycrystalline models taking an explicit account of the grain morphology and crystallographic orientations are generated by the method of step-by-step packing. A crystal plasticity-based constitutive model describing the nonlinear behavior of individual grains is implemented in a dynamic boundary-value problem that is solved by the finite-element method. Two sets of calculations for polycrystalline models with textured and non-textured surface layers are performed. The basal texture of the surface layer is shown to effectively suppress surface roughening, both at the grain and mesoscales. [ABSTRACT FROM AUTHOR]

7xxx series aluminum alloys are used to manufacture machine components with good strength and low mass. The application of thin surface films can improve the erosion resistance of these alloys and their corrosion resistance, which are scarce. Low temperature PVD (Physical Vapor Deposition) coatings can increase the surface properties of the components without greatly influencing the mechanical properties. The deposition process induces high residual compressive stress on the surface, which favorably modifies the fatigue strength, but also defects, which have the opposite effect. The changes in fatigue behavior of 7075-T6 alloy induced by the deposition of a surface layer of PVD DLC (Diamond-Like Carbon) are described in this paper. The tests performed on some uncoated samples and others with DLC show that the fatigue strength of the uncoated samples is higher within 2·105 - 107 cycles range. The fatigue strength of the two kinds of samples is approximately equal within the range of 2·106 - 107 cycles. The failure mechanism is studied with the help of fracture surface microscopy and finite element analysis. The compressive stress state on the surface of the specimen associated with the surface layer deposition causes fatigue crack initiation under the surface of the specimen, if the sample does not present defects. [ABSTRACT FROM AUTHOR]

The paper deals with investigations of a crack propagating in a semi-circular concrete disc loaded in bending. Various crack inclination angles ensure different degrees of I+II mixed-mode conditions. Generally, concrete material exhibits quasi-brittle fracture behavior, which is difficult to describe. It has been shown that fracture in this kind of material occurs in a larger zone around the crack tip. Thus, the multi-parameter fracture mechanics concept can help to understand the facture response better. Particularly, the Williams power expansion with a selected number of its initial terms is used for approximation of the crack-tip stress/displacement field. The over-deterministic method together with a finite element analysis of the problem is used for calculation of the coefficients of the series. The deflection angle of the initial crack is then assessed via generalized/multi-parameter form of Maximum Tangential Stress (MTS) criterion in dependence on various parameters. The theoretical results are compared to experimentally obtained data. The results prove that the multi-parameter description of the crack-tip fields can bring more accurate assessment of the fracture response of a crack under mixed-mode loading. [ABSTRACT FROM AUTHOR]

In this paper we present the implementation of a stabilized finite element method (FEM) in the computational fluid dynamics code for numerical simulations of supersonic and hypersonic flows using the Flux Correction Transport (FCT), and the results of computational experiments. The instabilities observed in FEM numerical solutions for supersonic flows reflect the fundamental problems of the FEM, and cannot be avoided with any finite element approach modifications. The papers published for scalar transport, (Kuzmin 2009), and for compressible flow problem, (Kuzmin, Moller 2010) provided a break-through approach for this problem, resulting in algorithms of increased stability and performance, by implementing this on the level of the matrix of the algebraic linear system, resulting from PDE discretization in the FEM. The FEM with the FCT results in a stable algorithm for accurate simulation compressible flows, examples of simulations and comparisons are presented. An additional advantage of this approach is that simulations can be performed with a much larger time step, with the Courant-Friedrichs-Lewy (CFL) condition 1 or more (up to 20) and get numerically stable long time transient, and stationary solutions. This results in a significant speedup of simulations (up 30X) compared to maximum possible CFL=0.03 for methods without FCT. Apparently our FCT implementation FEM for supersonic flows was the first at a time successful implementation following the invention of FCT into FEM by (Kuzmin 2010). [ABSTRACT FROM AUTHOR]

Italy is a high seismic risk country. Since 1900 more than 30 earthquakes with magnitude greater than Mw=5.8 occurred, and the last one is the Central Italy seismic sequence. The first shock aroused in the 24th August (Mw=6.2) followed by another stronger quake in the 30th October (Mw=6.5). It heavily hit the regions of Marche, Umbria, and Abruzzo causing many deaths, injuries and extensive damages on the cultural heritage. This paper analyses the church of San Francesco in Amadola, located in the Marche region that has been considered condemned for the severe damages reported after these earthquakes. The church is globally analyzed by the application of nonlinear static analysis on a Finite Element Model where the nonlinearity of masonry is taking into account with a proper constitutive law. The study wants to prove how global analysis combined by the local analysis can reproduce the behavior of this structure during a quake, showing that it can repeat the real damages produced by earthquakes. [ABSTRACT FROM AUTHOR]

In this paper, it is presented the dependence of calculation and speed of calculation when increasing integration points in the finite element of the enrichment type, which is used in the eXtended Finite Element Method (XFEM). The Legendre polynomial was used to increase the number of integration points and the Gauss quadrature was used for integration. A simple 3D model consisting of hexahedron was created for testing. [ABSTRACT FROM AUTHOR]

The paper is focused on reliability analysis of time-consuming mathematical models utilizing approximation in form of Taylor series expansion. Statistical analysis is crucial part of reliability analysis of structures but it is still challenging to analyze time-consuming mathematical models, e.g. represented by finite element method in implicit form. Efficient alternative is an approximation of original model by explicit function in specific form. The paper is focused on approximation by Taylor series expansion for statistical analysis of functions of random variables. Although it is common to use Taylor series expansion for functions of uncorrelated random variables, it is challenging to utilize Taylor series for correlated variables and highly non-linear functions. Therefore, possibilities and pitfalls of such approach are herein discussed from engineers point of view. [ABSTRACT FROM AUTHOR]

Modeling of concrete response using nonlinear constitutive equations is currently a very popular and promising field of science. Nowadays, there is already a number of different constitutive equations (material models) intended for concrete modeling in computational systems. These equations find their use mainly in the implicit or explicit finite element method and usually contain a lot of input parameters. However, the still inadequate exploration of this field of science provides the scope for algorithmization and application of other constitutive equations that can provide satisfactory results with relatively few input parameters. This fact is related to the goal of this paper that is algorithmization and application of constitutive equations intended for modeling the plane stress state of concrete. These equations are based on the incremental theory of plasticity in which some aspects such as yield function, hardening rule, non-associated flow rule, plastic hardening modulus, and equivalent stress and strain are applied. Algorithmization of constitutive equations is performed in Matlab and their application is focused on the tasks of uniaxial and biaxial compression of concrete for the purpose of demonstration of their capability to describe the concrete response in compression very satisfactorily. [ABSTRACT FROM AUTHOR]

In recent years, Micro-Mechanical Systems has been active area of research for their wide range of applicability. Various bimolecular sensing applications like the detection of DNA, Proteins and Antigens involve the adsorption of molecules that results in the change of surface stress. The effect of surface stress on the cantilever deflection can be analyzed based on the pressure applied at the free end of cantilever. MEMs use Cantilevers as the basic structures for sensing. Yet the practicality has not been extensive due to their low resolution and expensive read out techniques. Various physical and process parameters play a significant role in ascertaining the responsiveness of a cantilever sensor. This paper presents the analysis on the effect of different designs of Stress Concentration Region (SCR) on the change in deflection in microcantilever using Finite Element (FE) analysis. Design and analysis were done using Intellisuite thermal, electrostatic and mechanical (TEM) analysis tool for MEMS design. By applying Finite element method the simulations are performed. Simulation results show that the cantilever with proposed rectangular SCR design gives the highest deflection thus contributing to the most significant result for cantilever readout. [ABSTRACT FROM AUTHOR]

This paper investigates the normal stress and shear strain of a single lumen microcatheter. A microcatheter is a nominally invasive device used in intracranial and neurovascular therapeutic disorders. Finite element method is used to analyze the stress-strain variations in all the three layers of the microcatheter. The stress-strain distributions are studied to incorporate an efficient and robust design to improve tractability of the microcatheter. The main objective of this paper is to make the microcatheter cost effective for the society by employing a robust design. A novel design of the microcatheter is done using a high-end three-dimensional modelling software inhibiting bends along the length to determine the failure criterion in one or all the three layers. The design of the braiding can be re-calibrated such that it can avoid shear failure of the inner layer. The dorsal tip of the microcatheter can be programmed using artificial intelligence using smart alloys (SMA) on the inner surface so it can take any shape according to the pathway inside the body. [ABSTRACT FROM AUTHOR]

In this paper micro-electro-mechanical systems (MEMS) deformable mirror (DM) for its use in adaptive optics in Indus-2 is studied. DMs are used to correct optical aberrations by precisely adjusting the deflection of mirror surface. A piezo based micro-actuator array of 19 keystone shape elements in diameter of 10 mm on silicon of 20 µm thickness is considered for the study. The finite element method (FEM) simulations were carried out using COMSOL Multiphysics 5.4 to estimate the displacement profile. In order to evaluate the applicability of this MEMS based DM in adaptive optics system, piezo response function matrix was determined by applying dc voltage of 1volt to each actuator one by one while keeping the others at zero voltage. The optimum voltage of each actuator to produce a target profile was determined using TLBO algorithm in MATLAB. In this way the obtained voltages are used to generated the low order Zernike mode shapes. [ABSTRACT FROM AUTHOR]

The paper presents the influence of dynamics of temperature field on three-layered annular plate with elastic and viscoelastic core. Plate is mechanically loaded in the plane of facings on outer perimeter with the forces quickly increasing in time. Temperature field is determined by the temperature difference between the plate edges, which increases in time with the adopted value of thermal rate. Problem is solved analytically and numerically using the approximation methods: orthogonalization and finite difference. To compare the plate reactions the model built in finite element method has been examined, too. Presented results show the meaning of the dynamic parameters of both mechanical loading and thermal field on the plate respond. The direction of the gradient of temperature difference causes the increase and decrease in values of critical plate parameters and can be the means of controlling of plate work in dynamic conditions. [ABSTRACT FROM AUTHOR]

This paper is concerned with the numerical solution of the structural optimization problem for bilateral frictional contact problem where the static elasto-plastic material model with linear kinematic hardening rather than elastic material model is assumed. The displacement and stress of the bodies in elasto-plastic contact are governed by the system of the coupled variation a line qualities. The contact stress usually is very high in central part of the contact zone and leads to wear or fatigue of the contacting surfaces. Therefore the aim of the structural optimization is to find such shape of the domain occupied by the body in contactor such distribution of the material filling this body to minimize the contact stress. Using von Mises yield function as well as the regularization and penalization techniques the original system of variational inequalities is transformed into the system of non linear equations. The shape derivative of the cost functional with respect to the perturbation of the domain is calculated using the material derivative method. Finite element method is used as the discretization method. In the numerical computations generalized Newton method is used to solve the contact problem. The level set method is used to describe and govern the evolution of the domain shape in the design space where the direction of the evolution is determined based on the calculated shape derivative. The results of computation are provided and discussed. [ABSTRACT FROM AUTHOR]

Metaheuristic algorithm is preferred by the many researches to find the minimum weight of truss structures considering size and/or shape design variables which are the truss element’s cross-sectional area and joint coordinates of the geometry of the trusses for the size and shape optimization, respectively. The design of plane and spatial truss structures are optimized by a popular metaheuristic optimization technique named Teaching-Learning-Based Optimization (TLBO). Finite element analyses of structures and optimization process were carried out by the computer program coded in MATLAB visually developed by the authors. Two benchmark problems (37-bar, and 72-bar) taken from literature were optimized and the optimal solutions belong this paper were compared with previous studies. [ABSTRACT FROM AUTHOR]

The Bonded repair is broadly used in aging aircrafts to improve the structural integrity of damaged aircraft panels. The aim of this paper is to study the behaviour of multiple cracks on the flat panels using FEA. In this paper two twin collinear cracks are modeled and analyzed in terms of stress intensity factor(SIF). To improve the strength of the panel with multiple cracks it is repaired by adhesively bonded composite patch. It is shown that bonded repair reduces SIF near the crack tips of multiple cracks. Further, the adhesive is the weakest link which undergo failure under the applied load. Hence in this work debonding analysis of patch from the panel is carried out by appling load in increments. From the debonding analysis it is observed that the debonding of patch reduces the strength of repaired panel and leads to rise in SIF at the crack tips. [ABSTRACT FROM AUTHOR]

The paper presents the results of numerical calculations of dynamic loading of thin cylindrical targets with a ratio of cylinder heights to its diameter 1 : 1 and 5 : 1. The propagation of elastic waves in cylinders with different ratios of heights to the radius of the VZhM8 single-crystal nickel alloy with cubic symmetry of properties in order to determine the propagation velocities of rod waves in the [001], [011] and [111] directions was simulated in this paper. The problem of loading of a target from VZhM8 by a steel projectile with a starting velocity was carried out by the finite element method in a three-dimensional formulation. [ABSTRACT FROM AUTHOR]

Photonic crystal is a periodic arrangement of dielectric rods positioned in air at optimal spacing. Photonic crystal properties depend on the geometrical parameters such as material, radius of rods, lattice constant etc. This paper examines Photonic Band Gap (PBG) due to change in radius of rods and lattice constant of 2D photonic crystal structure. A detailed study of the PBG of 2D photonic crystal structure has been presented using Finite Element Method (FEM). A line defect is introduced into the photonic crystal structure and its impact on PBG has been investigated. The results show that after increase in radius of rods PBG becomes wider, whereas increase in lattice constant decreases the width of bandgap. [ABSTRACT FROM AUTHOR]

Spring clip are widely used in modern rail fastening systems. Cyclically varying stress appear in the spring clip when the railway vehicle passes. This leads to fatigue cracks in the spring clip and their subsequent destruction. Thus, increasing the fatigue strength of spring clips is an urgent task in the development of railway transport. The paper considers a spring clip in the fastening of a rail with reinforced concrete sleepers (fastening ZhBR-65). The finite element modeling of the loading process of the ZhBR-65 spring clip has been carried out. The maximum stress intensity σi was 411 MPa. A new design of a spring clip has been developed, in which the arc sleeper sections (adjacent to the sleepers) are made with a barrel-shaped cross-section. The safety factor of the resulting structure is 1.22 times higher than that of the standard ZhBR-65 spring clip. [ABSTRACT FROM AUTHOR]

As the resolution of digital images increases significantly, the process of images becomes more challenging in terms of accuracy and efficiency. In this paper, we consider image segmentation by solving a partial differential equation (PDE) model based on the Mumford-Shah functional. We develop a new algorithm by combining anisotropic mesh adaptation for image representation and finite element method for solving the PDE model. Compared to traditional algorithms solved by the finite difference method, our algorithm provides more efficient results without the need to downsample the image to a lower resolution. [ABSTRACT FROM AUTHOR]

This study uses numerical simulation to examine how coil turns affect the parameters (characteristics) of argon discharges in a 2D axisymmetric inductively coupled plasma (ICP) torch operating at 0.02 torr pressure. In this paper we us different number of coils turns (3-6) and a steady power 1500 w. Inductively coupled plasma is a type of radio frequency discharge (RF discharge) In order to optimize the ICP torch, this study develops a mathematical model of balanced discharge by COMSOL using finite element method (FEM) and investigates the number of coil turns' effect on plasma torch characteristics. In this simulation, argon gas was used and a radio frequency of 13.56 x 106Hz on the ICP chamber. The goal of this work is to get a better understanding of the effect of coil on the ICP parameters (number of electron density, electron temperature, number of ion density, number of excited argon density) in a ICP chamber. [ABSTRACT FROM AUTHOR]

Steel coupling beam is a substantial member in hybrid coupled walls system that greatly enhance the strength and the energy dissipation capacity of the system compared to coupled walls linked by convention reinforced coupling beams and diagonally reinforced coupling beams. To enhance these characteristics even more, a corrugated web may be used instead of the traditional flat web. This paper presents a numerical analysis using finite elements software (ABAQUS) to investigate the nonlinear behavior of both types of steel coupling beams (with flat web and with corrugated web). The effect of initial imperfection on the nonlinear behavior of steel coupling beams was taken into account. The results were compared with the available experimental data of steel coupling beams with the flat web. Good agreement was noticed between the experimental and the numerical results. Among the conclusions drawn in this study is that using a corrugated web as an alternative to a flat web may increase both the strength and the energy dissipation of the steel coupling beams. [ABSTRACT FROM AUTHOR]

The most important main characteristics of wireless transmission system transformers (WPT) are coupling coefficient, self-inductance, and mutual inductance, which directly affect the efficiency of the system. Due to the unique and complex nature of transformers, a finite element method (FEM) calculation was used to determine these parameters using the Ansys Maxwell software. This paper introduces and discusses the characteristics and shapes of pads with emphasis on round pads, and the effect of ferrite quantity on the coupling modulus. The system results showed that the coupling coefficient is significantly affected by increasing the amount of ferrite and lesser by changing the shape of the ferrite. Also proved that it is affected by increasing the amount of overlapping space for the files by changing the shapes of the files to flat, concave and convex. [ABSTRACT FROM AUTHOR]

Squirrel cage induction motor (SCIM) plays an important role in industrial applications thanks to its hardness, durability, and ease of design. With all these advantage researches are still being conducted to improve the performance of the induction motor because it suffers from problems such as low power factor as well as ripple torque and low efficiency. the main objective of this paper is to discuss the increasing of the starting torque and decreasing the ripple torque as well as increasing the efficiency of the squirrel cage induction motor based on specific methodologies carried out on the rotor bar by changing its position in the horizontal and vertical direction as well as implementing the skewing effect on rotor bar and analyzing the impact of each of these changes on the performance and efficiency by using finite element method (FEM). [ABSTRACT FROM AUTHOR]

This paper presents the results of testing popular composite materials used for FDM printing. The copolymers used for the analysis were acrylonitrile-butadiene-styrene (ABS) and polylactide (PLA). A 3D printer placed in a transparent chamber equipped with electronic probes to record the temperature within the print head, work table, and volume was used to prepare the prints. The 3D model for the study was designed in Autodesk's Inventor software and a preliminary dynamic simulation of uniaxial tension was performed using the finite element method (FEM). The simulation was used to predict von Mises stresses and strains in the test specimens. The specimens were subjected to static tensile testing on a testing machine and the simulation results were compared with the results of laboratory tests of the printed parts. The research aimed to obtain information on the mechanical properties of selected composite materials intended for use in the construction of components of laboratory bioreactors. [ABSTRACT FROM AUTHOR]

Amphibious aircraft are needed in many areas in Indonesia that are difficult to reach by air transportation. With this amphibious aircraft, an amphiport is needed for aircraft to land on water. This amphiport requires a lower cost when compared to airport infrastructure. Due to the different landing sites, the load response that occurs on the seaplane structure at the time of landing will be different. In this paper, we will try to predict the pressure that occurs on the surface of the float when the aircraft lands on the water. The prediction is carried out by numerical simulation using software. Numerical simulations were carried out with several variations of angle of attack and several heeling conditions, namely 0, 5, and 10 degrees for trim by bow and trim by stern and 0, 5, 10, and 18 degrees for heeling conditions. This modeling has been verified by sensitivity meshing analysis. From the results of this study, it is obtained that the greater the angle of trim, the greater the maximum pressure that occurs on the surface of the float. Likewise with the heeling condition, the greater the angle of heeling, the greater the maximum pressure that occurs on the surface of the float. A structural assessment using the Finite Element Method (FEM) is recommended to determine whether the float structures are strong enough. The load or pressure obtained from the above research will be applied to the FEM. [ABSTRACT FROM AUTHOR]

Consideration of uncertainties in bridge structural engineering is a growing topic because it provides valuable information on the reliability of bridges in time while addressing life-cycle aspects. Utilization of nonlinear finite element method (NLFEM) and Monte Carlo (MC) type simulation is essential for modelling of the concrete bridge random behaviour and its reliability assessments. Generally, a physical problem can be represented by a mathematical model, which depends on input parameters (material characteristics, geometry, etc.). The aim of the stochastic analysis is to propagate uncertainties through a mathematical model to gain statistical information from the output as well as information about the sensitivity of the mathematical model to uncertainties in input variables. However, in bridge engineering, the mathematical model can be quite complex and uncertainty propagation solved by classical MC approach is very difficult to perform as MC type simulation involves large number of numerical evaluations of structural response. Therefore, advanced statistical and reliability techniques, including meta-modelling, have to be applied. The paper describes methodology of such integrated approach for a routine complex assessment utilizing developed software tools and practical application of the approach for selected case studies of concrete bridges from Czech Republic. [ABSTRACT FROM AUTHOR]

Existence of defects (such as cracks, pores, inclusions etc.) in steel structures is nearly unavoidable and therefore, investigations on their behaviour and the structural integrity of the structure are necessary. Additionally, it is observed that such defects can interact with corrosion pits, which are important consequences of the other phenomenon related to steel structures. Therefore, this paper is devoted to a study on the influence of the corrosion pit on fatigue crack propagation under mixed-mode I/II loading conditions. A rectangular bar subjected to remote tensile loading is modelled numerically by means of the finite element method and principles of the linear elastic fracture mechanics are applied. Several conclusions are stated on the effect of individual parameters varied within the study on the crack propagation. More extensive studies are intended in the field of crack deflection etc. [ABSTRACT FROM AUTHOR]

In this paper, the effect of face sheet thickness on the bending behavior of sandwich beams was investigated. The structure used for analyses was a composite sandwich beam with aluminium as skin and epoxy as core. Finite element analysis was carried out on the structure using ABAQUS software. To investigate the bending of the composite beam, three-point bending tests were performed on the material and mid-span deflections were recorded. Different results such as force vs deflection, mass, and Von Mises stress were obtained and analyzed by changing the thickness of core. Research findings revealed that the thickness of beam skin affected its mass and flexural stiffness. Moreover, as the thickness was increased, deflection was decreased if the same force was applied to the beam. As the thickness of the face was increased, beam mass was also increased. Finally, we observed that the beam with the highest thickness had the biggest Von Mises stress when the same deflection was required for different face thicknesses. [ABSTRACT FROM AUTHOR]

The paper deals with static analysis of homogeneous as well as FGM (functionally graded material) thin micro/nano piezoelectric plates subjected to static loading. within the higher-grade continuum theory of elasticity. The microscopic structure of material is reflected in this higher-grade continuum theory via one material coefficient called the micro-length scale parameter. Furthermore the material can be composed of two micro-constituents what is included in the employed continuum model by functional gradation of the material parameters through the plate thickness with assuming power-law dependence of volume fractions of micro-constitue nts on the transversal coordinate. The high order derivatives of field variables are eliminated by decomposing the original governing partial differential equations (PDE) into the system of PDEs with lower order derivatives. For the numerical implementation, the strong formulation is proposed with novel Moving Finite Element approximation method of spatial variations of field variables. Several numerical simulations are devoted to study the influence of micro-length scale parameter as well as the parameters of gradation of material parameters on coupled bending and in-plane deformation response modes and also on the electric potential. [ABSTRACT FROM AUTHOR]

The paper reports on Finite Element Analysis (FEA) and shape optimization of the automobile brake lever. Finite element analysis was carried out in the finite element tool. The first part of the research was a comparative study of Finite element analysis using real life data collected for polylactide (PLA) samples. The stress and deformations were analyzed on the Brake lever using ANSYS tool so as to compare and achieve safer design. Purpose of the Finite Element Analysis is to optimize the shape of the Brake lever in order to ensure adequate safety and ergonomics of use. The induced stress was well within maximum permissible limits for the material used during its operation. The obtained results have been validated using published data. [ABSTRACT FROM AUTHOR]

Vibration isolators are highly useful for reducing the amplitudes of oscillations during the operation of the heavy machines in the industries and research laboratories. When the machine operates at the natural frequency of the component resonance takes place, leads to violent oscillations, violent noise causes severe damage of the structure. In order to reduce the transmission of vibrations and minimize the damage of the structure, effective vibration isolators are important and the type of materials also important for optimum operation. In this paper, therefore, total deformation, unidirectional deformation, equivalent elastic strain, maximum principal elastic strain, minimum elastic strain, of spring type vibration isolator (STVI) made of AluminumAlloy(ALY), Gray Cast Iron(GCI) and stainless steel(STS) are calculated by using the finite element analysis. Optimized STVI is the main spring made of SLS. [ABSTRACT FROM AUTHOR]

Thermoforming process has now become the most suitable and conventional method for manufacturing 3D circuits with complex geometries. The mold of commercially available automobile lighting LED is developed using CNC machine. The stretchable circuit is printed on a thermoplastic substrate through screen printing technique before undergoing thermoforming process. The factors that affect a thermoformed product are the stretch level and thickness reductions of the substrate. This paper aims to study the effect of the variation in dimensions of the thermoformed product without the printed stretchable circuit on the substrate. Finite element methods (FEM) analysis is also carried out in order to visualize the behavior of the substrate in terms of area stretch ratios (ASR) and thickness reductions of different wall surfaces after deformation according to the geometry of the mold. The ASR and thickness values obtained by experiment and simulation are compared. As a result, the simulated values are bit higher than the experimental ones but they are acceptable, therefore, the behavior of thermoforming product like large stretch areas and less thickness, can be determined prior to the actual thermoforming process of the product with printed stretchable circuit. [ABSTRACT FROM AUTHOR]

Low velocity impact is a massive problematic issue causing a damage to the thin plate from the dynamic impact velocity below than 10 m/s especially the impact effects of coal pulveriser at coal powerplant sector. This paper presents the damage behaviour of 11% Manganese Steel plate structures when subjected to dynamic loading at flat (0°) and oblique plate of 45°.and 60° at different height which means different velocity of free fall (6.26 m/s, 7.67m/s, 8.85m/s and 9.9m/s). Experimental was examine thoroughly from strain test using mild steel and simulation development to validate the strain result assigning mild steel properties in Abaqus. This procedure is vital for understanding validation methods procedure. Furthermore, 11% Manganese steel was applied corresponding with model simulation validation from literature by extracting the Mn-steel's mechanical properties from the previous researcher work. After the validation, the geometry was altered based on actual situation of coal impact and thin plate dimension for further damage impact analysis. Finite element Analysis (FEA) was built generally for validation purposed and damage analysis by identified several parameters that influence the result. Flat plate, 0° at the highest velocity 9.9 m/s create significant damage based on highly mass loss compare to others variable because has a greater contact force and energy absorption of Mn-steel plate. Other than that, thickness modification was generated to reduce the damage where 10 mm minimize the damage up to 0.8% of the first impact whereas different material set-up was utilized from Shape Memory alloys (SMA) that cause no visibly damage at all due to high fracture-resistance. [ABSTRACT FROM AUTHOR]

This paper presents a finite element analysis of failure at the first stage (L-1) blade in a low-pressure 220 MW steam turbine. A crack was found at the leading edge vane of the fourth stage of some blades. The crack existed almost at the same position at several L-1 blades. Steam flows through the stationary blade and then pushes the moving blade, making the rotor rotates at high speed. The steam pushes a rotating blade by fluctuating pressure depending on the blade number and rotating speed. The effect of steam dynamics pressure on a blade's harmonics response and harmonics stress is investigated by finite element analysis using MSC Patran/Nastran 2019. Blade analysis was realized together with verification of the contact model between the blades. Two rotating blades are connected using a fixed round pin at the outer diameter of the blades. The result shows that when the pin contact model between the blades is bonded, the maximum dynamics stress works at the root blade caused by flexural elastic motion. Otherwise, when pin contact is touching or having looseness, the maximum stress occurs at the leading edge vane of the blade due to the torsional elastic mode. [ABSTRACT FROM AUTHOR]

It is meaningful to apply the finite element method to simulate the rupture process of ground motion, and then to study the related problems of active fault after the earthquake. This paper quantitatively analyzes the effect of the fault rupture with the finite element method on the regional plate tectonic stress field after a strong earthquake of Yushu MS7.1 in 2010. The mechanism of seismic fault rupture is preliminarily discussed through the distribution of displacement, stress, and energy fields. The results show that the earthquake did not trigger a strong adjustment activity of the ground stress near the regional plate. At the same time, the elastic strain energy distribution after the earthquake fault rupture is closely related to the fault length and the distance between the faults. The influence of the local strong earthquake on the tectonic stress of the regional plate can be comprehensively analyzed through FEM simulation. [ABSTRACT FROM AUTHOR]

Through the advent of micro dimensioned devices, we are in the need of alternate energy sources. In this paper PEM concept is discussed as alternate fuel cell. Concept of passive convention is studied and analyzed in terms of fuel cells with equal current density and heat evaporation throughout the structure. Finite element analysis is used to study the device and respective findings are categorized with variations of thermal profiles and current densities. [ABSTRACT FROM AUTHOR]

The L7e commercial vehicle is a four-wheeled vehicle that can be designed to meet less stringent requirements compared to normal cars. The curb weight of the L7e commercial vehicle is limited to 600 kg, not including the mass of the batteries in the case of electric vehicles with a design load capacity of 1000 kg or less. Such a high load capacity with low curb weight complicates the selection of the suspension stiffness, which must be non-linearly progressive. The authors of the paper decided to support the design process with the non-linear finite element method due to large deformations, contact and friction between interleafs and the rubber elements between interleafs and the mounting bushings. The proposed method of stiffness evaluation was validated by modelling and experimental testing of commercially available non-linear leaf spring. The article presents the methodology of CAD and FEM modelling, as well as the experimental test stand testing of leaf spring stiffness characteristics. Results of FEM analysis and experimental testing were analysed and the accuracy of proposed method was evaluated. [ABSTRACT FROM AUTHOR]