Search

Calculations of reinforcement of "D" regions of reinforced concrete structures is much d ifficult than for "B" regions and demands some specific approaches. Authors of the paper suggest to use both Strut-and-Tie (S&T) and Finite Element Method (FEM). The first of those methods allows to calculate required reinforcement and efficiency factor. In turn FEM can not only confirm S&T results but also gives information about crack width and pattern, strains and nodal displacement. Sample calculations were performed on example of frame corners under opening bending moment. Parameters of Concrete Damaged Plasticity model of concrete implemented in Abaqus were calibrated in tension and compressions test. [ABSTRACT FROM AUTHOR]

It is common in full-scale laboratory tests to simulate live or transient loads of secondary importance with generic weights, even if the load being simulated is uniform in nature. For many simple structures, such as beams or plates, calculation of appropriate substitute load is rather straightforward. The paper deals with somewhat more difficult case of orthotropic plates, which are common solutions for fire resistant roofs. The main load of these structures in tests according to EN 1363:2012 [1] is temperature, but uniform load must also be included in the tests. A numerical algorithm is proposed to beforehand calculate an applicative load, which preferably would not impair neither favour the test specimen. A FEA model of the roof specimen is built and optimisation algorithm seeks for the solution, taking into consideration all of the arbitrarily formulated constraints for the load distribution and a set of independent objective functions. In the paper, few such objective functions, appropriate in this kind of tests, are discussed. [ABSTRACT FROM AUTHOR]

Since the first paper published in 2005 Isogeometric Analysis (IGA) has gained strong interest and found applications in many engineering problems. Despite the advancement of the method, there are still far fewer software implementations comparing to Finite Element Method. The paper presents an approach to the development of data structures that can support multi-region IGA with local mesh refinement (patch-based) and possible application in IGA-FEM models. The purpose of this paper is to share original design concepts, that authors have created while developing an IGA package, which other researchers may find beneficial for their own simulation codes. [ABSTRACT FROM AUTHOR]

The paper is devoted to the evolutionary identification of the material constants of porous structures based on measurements conducted on a macro scale. Numerical homogenization with the RVE concept is used to determine the equivalent properties of a macroscopically homogeneous material. Finite element method software is applied to solve the boundary-value problem in both scales. Global optimization methods in form of evolutionary algorithm are employed to solve the identification task. Modal analysis is performed to collect the data necessary for the identification. A numerical example presenting the effectiveness of proposed attitude is attached. [ABSTRACT FROM AUTHOR]

This paper presents modelling of both single and double-phase powder sintering processes at the macroscopic level. In particular, its constitutive formulation, numerical implementation and numerical tests are described. The macroscopic constitutive model is based on the assumption that the sintered material is a continuous medium. The parameters of the constitutive model for material under sintering are determined by simulation of sintering at the microscopic level using a micro-scale model. Numerical tests were carried out for a cylindrical specimen under hydrostatic and uniaxial pressure. Results of macroscopic analysis are compared against the microscopic model results. Moreover, numerical simulations are validated by comparison with experimental results. The simulations and preparation of the model are carried out by Abaqus FEA - a software for finite element analysis and computer-aided engineering. A mechanical model is defined by the user procedure "Vumat" which is developed by the first author in Fortran programming language. Modelling presented in the paper can be used to optimize and to better understand the process. [ABSTRACT FROM AUTHOR]

Pultruded Fiber Reinforced Polymers (FRPs) have been increasingly used in civil infrastructure applications due to advanced properties such as high specific strength, lightweight and especially high corrosion resistance. In highly corrosive environment such as chemical and acid environment where metallic by-products are prone to corrosion, the use of adhesive bonding in addition to FRP bolts not only decreases the structure's weight, limits the impacts of aggressive environment but also increases the ultimate strength of the connection and improves the connection stiffness. In this paper, mechanical behavior of pultruded FRP double-lap specimens combined by only FRP bolt as well as both FRP bolt and adhesive under tension tests was investigated by finite element method and experimental data. Two kinds of used adhesive were high strength adhesive and low elastic one. Results show that comparing with bolt-only specimens, connections with both FRP bolt and adhesive had the higher joint strength. Specimens with high strength adhesive had the highest joint strength but the shear out failure and delamination at FRP plates happened suddenly while the low elastic adhesive specimens witnessed the debonding failure and shear out failure alternately in the both sides of connections. Moreover, the stress distributions in the GFRP plates were also investigated and there were good agreements between finite element analysis (FEA) and experimental data achieved in this paper. [ABSTRACT FROM AUTHOR]

End-plate connections with preloaded high strength bolts represent a convenient, fast and accurate solution for beam-to-column joints. The behavior of framework joints build up with this type of connection are sensitive dependent on geometrical and material characteristics of the elements connected. This paper presents results of parametric analyses on the behavior of a bolted extended end-plate connection using finite element modeling program Abaqus. This connection was experimentally tested in the Laboratory of Faculty of Civil Engineering from Cluj-Napoca and the results are briefly reviewed in this paper. The numerical model of the studied connection was described in detail in [1] and provides data for this parametric study. [ABSTRACT FROM AUTHOR]

A hybrid glass/aluminum/titanium fiber metal laminate (FML) based on the standard GLARE concept was proposed in present paper, and its notched behavior was investigated experimentally and numerically. Experimental results revealed that a special three-stage stress-stain curve was obtained by this reinforced GLARE, which was related to the transition of load bearing mechanism. As well as, improvements of notched strength and normalized notched strength were achieved benefiting from the high strength and ductile nature of titanium, where their maximum increments obtained at D/W=0.2 were 11.88% and 15.40%, respectively. In addition, numerical results indicated that the finite element model (FEM) predicted well the notched behavior of GLARE with incorporating the thermal residual stress effect. Moreover, the comparisons of internal energy and damage dissipation energy between standard GLARE and reinforced GLARE have facilitated in the understanding of reinforced effect of titanium. It is believed that the present investigation can provide some useful information for damage tolerance design of FMLs. [ABSTRACT FROM AUTHOR]

Rollovers are complex road accidents causing a big deal of fatalities. FE model for rollover study will costtoo much time due to its long duration. A new multi-body modeling method is proposed in this paper which can save a lot of time and has high-fidelity meanwhile. Following works were carried out to validate this new method. First, a small van was tested following the FMVSS 208 protocol for the validation of the proposed modeling method. Second, a MADYMO model of this small van was reconstructed. The vehicle body was divided into two main parts, the deformable upper body and the rigid lower body, modeled by different waysbased on an FE model. The specific method of modeling is offered in this paper. Finally, the trajectories of the vehicle from test and simulation were compared and the match was very good. Acceleration of left B pillar was taken into consideration, which turned out fitting the test result well in the time of event. The final deformation status of the vehicle in test and simulation showed similar trend. This validated model provides a reliable way for further research in occupant injuries during rollovers. [ABSTRACT FROM AUTHOR]

Lamb waves are widely used in nondestructive testing (NDT) and structural health monitoring (SHM) for its obvious advantages, such as good directionality, longer-range propagation and lower loss etc. However, it is difficult to analysis and to interpret the echo signals because of its multi-modes and dispersion. In this paper, the properties of single-mode Lamb waves which were excited by double EMAT were studied based on the principles of multi-modes and the characteristics of wave structure. Simulation results show that the double transducer excitation structure can stimulate single-mode Lamb waves and eliminate the extra modes, which are produced by modal conversion at ends of the specimen. The single-mode excitation of Lamb waves is beneficial to reduce the difficulty of signal processing and provide reliable information to locate the defect. The researches in this paper can be used as a theoretical basis to design double transducer excitation system. [ABSTRACT FROM AUTHOR]

This paper is devoted to the so-called semianalytical structural analysis based on combined application of finite element method (FEM) and discrete-continual finite element method (DCFEM). Boundary problems of threedimensional theory of elasticity are under consideration. In accordance with the method of extended domain, the given domain is embordered by extended one. The field of application of DCFEM comprises structures with regular (constant or piecewise constant) physical and geometrical parameters in some dimension ("basic" dimension). DCFEM implies finite element mesh approximation for non-basic dimension of extended domain while in the basic dimension problem remains continual. Corresponding discrete and discrete-continual approximation models for subdomains and coupled multilevel approximation model for extended domain are under consideration. The paper presents brief review of software and verification samples. [ABSTRACT FROM AUTHOR]

The article is devoted to the method of estimation of the effective mechanical properties of rocks by performing numerical calculations on the digital model of core. The digital model of core is constructed in the form of structured hexahedral grid based on CT scan data. In the representative volume element (RVE) of the core sample, a number of boundary value problems of the elasticity theory with various boundary conditions are solved. The pre-loading of the rock caused by pore pressure is also taken into account. The elasticity problems are solved numerically with the help of finite element method using CAE Fidesys. The results of the solution of each problem are averaged over the volume. Effective properties of core are estimated in the form of the generalized Hooke's law. The paper presents the results of calculations carried out at variable pressure for core made by one (sandstone) and several (pyrite, solid and solid calcite) minerals. It is shown that the dependence of the estimated elastic moduli on the pore pressure is linear. [ABSTRACT FROM AUTHOR]

The creation of functional materials is a promising direction for engineering development. Functional materials include metamaterials among others. Metamaterials achieve the required properties using a rationally designed structure. Tetrachiral structures differ from the others in that they can twist under uniaxial loading. This paper solves the quasi-static problem of uniaxial loading within the framework of linear elasticity theory using the finite element method. It is investigated how the support reaction changes when a second ring is added into the chiral structure. The dependence obtained suggests that by adding a complementary ring and increasing its size more forces have to be applied to deform the metamaterial. It is shown how the size of the secondary ring affects Young's modulus. [ABSTRACT FROM AUTHOR]

This paper presents an approach for a stabilization of contact penetration in the finite element method using the explicit method. The key issue is to avoid the large penetration during a calculation of a one time step which may cause instability of a solution and that is why usually requirement for very small time step arises. [ABSTRACT FROM AUTHOR]

In this paper, presents the stress intensity factor in linear elastic fracture mechanics. A simple model was created in the program Abaqus. Two variants were compared, namely the solution using the finite element method and the extended finite element method. The stress intensity factor is then used in both methods, where there are many criteria for crack propagation decisions, which is further used in these methods. [ABSTRACT FROM AUTHOR]

In this paper, we propose a weak Galerkin mixed finite element method (WG-MFEM) based on Crank-Nicolson discretization to solve parabolic problems. The basic idea to WG-MFEM is to apply discrete weak divergence operator which is locally defined on each element. Optimal order error estimates in H1 norm and L2 norm are derived. Finally, we discuss some numerical results to verify our theoretical findings. [ABSTRACT FROM AUTHOR]

The aspects of building a transformation function for a multicomponent sensor based on the methods of finite element approximation of functions of several variables, as well as approximation using neural networks, are considered in this paper. Testing of mathematical models, computational methods and developed data processing algorithms was carried out on the experimental data of the calibration of a six-component “6ТВ203” sensor. The analysis of the obtained experimental data is carried out and the metrological characteristics of the sensor are determined. The computational algorithms for the use of the finite element and neural network approximations in modern measuring and computing systems have been developed and tested. It is shown that the use of finite element and neural network approximation allows one to improve the measurement results. [ABSTRACT FROM AUTHOR]

The objective of this work is to replace laboratory testing of cranial orthosis design with virtual prototyping. The stiffness of cranial orthosis will be evaluated by means of numerical modelling and simulation and will replace the necessity of physical testing of each and every new design of cranial orthosis to ensure its proper behaviour. In this paper we present development and validation of the numerical model as well as testing of the virtual prototyping approach using simplified model for purpose of design of the 3D printed cranial orthoses. [ABSTRACT FROM AUTHOR]

Geometric nonlinear solution of beam structures is presented. Basic assumptions are specified and incremental conditional equations are derived. Newton-Raphson iteration is used. Two finite element approaches are analysed in presented paper. The importance of nonlinear terms in geometric equation and their effect upon the result of the solution is the basis of this contribution. The solved examples of selected structures are presented and different approaches to the solution are compared. [ABSTRACT FROM AUTHOR]

This paper reports stress analysis of dynamic Si diaphragm under low pressure (~ 21 kPa). In this paper, finite element method (FEM) has been adopted within the frame work of COMSOL package in order to simulate displacement and stress profiles of silicon diaphragm at various frequencies. The simulated results show that for the 50 μm Si diaphragm, the fundamental frequency ~ 280 kHz is suitable and yields maximum and observable displacement and stresses and hence this frequency can be considered very much suitable for piezoresistive pressure sensor. [ABSTRACT FROM AUTHOR]

Pipes that carry gas into residential buildings are one of the most important infrastructures in cities. These pipes are prone to corrosion after a period of time because of different environmental factors. In order to avoid any pipe rupture that may cause explosion, the integrity of such pipes much be checked on a regular basis. Ultrasonic guided wave is an effective nondestructive testing (NDT) method for structural health monitoring (SHM) of plate like structures and pipes. However, the signals that are obtained from guided waves can be very difficult to interpret due to mode conversion, overlapped modes and low signal to noise ratio. In order to extract meaningful information of guided wave signals, using an advanced signal processing technique is inevitable. Most of the signal processing methods that have been developed so far, neglect the dispersion characteristic of guided waves. Dispersion means that the velocity of the propagating wave is a function of its frequency. As in most guided wave applications for inspecting pipes, we use narrowband tone-burst signal, dispersion causes guided wave signal to spread in time axis as it travels and changes its shape. Matching pursuit is one the greedy algorithm that can be used to approximate signals. This method iteratively approximates a signal by its predefined dictionary. However, the dictionary that usually contains redundant number of fundamental waveforms usually Gaussian signals may not be suitable for guided wave inspection of pipes. In this paper we designed a dictionary based on real guided wave signals by taking finite element method (FEM) approach. [ABSTRACT FROM AUTHOR]

The development of electric railway train has been growing rapidly in the last few years. Comfort is one of the important aspects in electric railway cabin, including the acoustic comfort. İn this paper, noise reduction efforts for air conditioning system of electric railway trains are discussed. Air-borne noise and structure-borne noise are considered while finite element analysis is used to study the contribution of each path to the total sound pressure level found in the passenger area. The air-borne noise control is realized by using the acoustic liner on the internal wall of the ducting where fibrous porous absorbers are used. This approach decreases the sound pressure level as much as 29.3 dB. Meanwhile, the structure-borne noise is reduced by placing a set of a parallel stiffener at the ducting wall. This approach can reduce the sound pressure level up to 28.9 dB at low-frequency range. Combining both of the acoustic liner and stiffener altogether can reduce the sound pressure level up to 37.1 dB by which the overall sound pressure level at passenger area is around 51.2 dBA. [ABSTRACT FROM AUTHOR]

The tea plucking quality is directly dependent on the performance of the cutter. To optimize the cutter, this paper proposes a new kind of cutter for tea plucking machine and focuses on the kinematic analyzing and modeling. The rigid-flexible coupling kinematics model was established based on the proper assumptions that the blade is deformable but unchangeable in length of the mid-surface. The model is more accurate than the rigid model established before, and used for describing the cutter’s motion accurately. And the equations were plot with MATLAB, providing a visible way to recognize the complex kinematics results. The model was applied to statics analysis with the finite element software (MSC Patran and Nastran), which verified that the blade meets the strength needs very well. This model is necessary complement for the cutting harvesting theory, provides the basis for optimal design of tea plucking machine, and would promote the plucking quality conspicuously. [ABSTRACT FROM AUTHOR]

Identification of parameters of laser beams is important in all applications of lasers. In this paper, results of numerical verification are presented for identification of parameters of pulsed, high-power laser beam based on displacement fields of the target body. It is considered how laser power as well as spatial and temporal characteristics of the beam may be recovered based on measurements of thermally-caused deformation of thin aluminum plate. Mechanical displacement of the plate surface was calculated using Finite Element Method (FEM), for selected time instants, based on solutions of the unsteady thermal problem obtained with Finite Volume Method (FVM). Sensitivity of measured displacements to changes of recovered laser pulse parameters is discussed. Preliminary results of parameter estimation based solely on measurements of the Z-component of displacement field were compared with results of estimations based on measurements of temperatures. The comparison was made for inverse problems solved using Levenberg-Marquardt method applying synthetic measurement data instead of physical one. It was found that solutions of the inverse problem based on temperatures are better than those based on mechanical analysis. [ABSTRACT FROM AUTHOR]

This paper presents the results of laboratory tests and finite element (FE) analyses of concrete cylinders subjected to compression. The laboratory tests of concrete elements were conducted to determine the secant modulus of elasticity and the nonlinear stress–strain relationship for concrete. This relationship was used to validate the numerical model of the concrete cylinders subjected to compression. The comparison between the numerical and experimental results indicates that the adopted 3D model captures the response of the concrete cylinders subjected to compression fairly well. [ABSTRACT FROM AUTHOR]

The paper presents the innovative process with possibility of predict the state of deformation and stresses in a two-stage metal forming process. In the first stage, regular surface roughness with arched outlines are embossed. In the second stage, these inequalities are flat burnished to obtain the required dimensions, roughness of the surface, and state of deformation and stresses in the surface layer of the workpiece. The process are considered as a geometrical and physical non-linear boundary and initial value problem, with unknown boundary conditions in the contact zone. The applications were developed in the Ansys/LS-Dyna system, which makes possible a complex time analysis of the states of displacements, strains and stresses, in the workpiece in the two-stage cold metal forming processes. Application of this method were showed for examples the modelling and the analysis of the regular asperities with arched outlines. In the simulations, the material as well as the geometrical parameters of surface asperities were changed. The simulation results were verified experimentally. [ABSTRACT FROM AUTHOR]

This paper concentrates on selected aspects of numerical modeling of a short span thin-walled beams. The performed numerical simulations cover different types of finite elements (shell or solid finite elements) and different mesh sizes. Moreover the shape and magnitude of an initial geometrical imperfection is also investigated. The numerical analysis were made with the Newton-Raphson procedure with geometrical and material nonlinearity. The numerical results were compared with the laboratory four point bending test of a thin-walled beam. Furthermore, some guidelines for numerical simulations of a short span thin-walled beams in bending were proposed by authors. [ABSTRACT FROM AUTHOR]

The paper addresses stress analysis of a strip with a circular hole under uniform uniaxial tension based on circumferential stress expression σθ. Stresses are analyzed in the infinite-length strips under tension with holes, the ratio of the hole radius a to the strip half-width b is either equal to: λ = a/b = 0.1 or λ = 0.5. Circumferential stresses are determined in selected cross-sections of the strip. The stress diagrams display local stress concentration near the hole. The analytical solutions are compared with the numerical solutions the finite elements method (FEM), the latter using the ABAQUS software due to various λ ratios. The results show the maximum circumferential stress at hole boundary, affected by the ratio of the hole radius to the width of the strip. [ABSTRACT FROM AUTHOR]

Technical elastomers are indispensable in the field of mechanical engineering, due to their material properties. Based on their damping characteristic, they are often used to avoid load peaks and to influence the vibration behavior of dynamically loaded systems. Nevertheless, elastomers have not been investigated as intensively as other materials in the field of damage accumulation and lifetime prediction. This paper presents a simulation model for lifetime prediction of elastomer components. The lifetime is defined as the number of load cycles till the global damage reaches the value 1. This damage is calculated by a failure criterion based on the change of a characteristic value like the dynamic stiffness degradation from a finite-element (FE) simulation. The presented lifetime prediction model uses a damage-dependent material model (Yeoh-Model) and a nonlinear damage accumulation model (nlSAM), which was developed at the chair of Engineering Design and Plastics Machinery at the University of Duisburg-Essen. Both models are calibrated by means of experimental data from dynamically loaded elastomer components. The nlSAM computes the local damage for each finite element depending on material stresses and pre-damage. The dynamic stiffness degradation is a result of locally changed material properties in the FE simulation due to the damage of each element. Finally, the lifetime prediction for unknown loads and different component geometries of the elastomer is carried out, which shows good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

The differential eigenvalue problem describing eigenvibrations of a simply supported beam with an attached load is investigated. This problem has an increasing sequence of positive simple eigenvalues with a limit point at infinity. To the sequence of eigenvalues, there corresponds a complete orthonormal system of eigenfunctions. We formulate a limit differential eigenvalue problem and prove the convergence of the eigenvalues and eigenfunctions of the initial problem to the corresponding eigenvalues and eigenfunctions of the limit problem as load mass tending to infinity. The original differential eigenvalue problem is approximated by the finite difference method on a uniform grid. Error estimates for approximate eigenvalues and eigenfunctions are established. The theoretical results are illustrated by numerical experiments for a model problem. Investigations of this paper can be extended to the cases of more complicated and important problems on eigenvibrations of plates and shells with attached loads. [ABSTRACT FROM AUTHOR]

The nonlinear second-order differential eigenvalue problem describing eigenvibrations of a bar with elastically attached load is investigated. The existence of an increasing sequence of positive simple eigenvalues with a limit point at infinity is established. To the sequence of eigenvalues, there corresponds a system of normalized eigenfunctions. The initial nonlinear differential eigenvalue problem is approximated by the finite element method on a uniform grid. The accuracy of approximate solutions is studied. The investigations in the present paper can be extended to the cases of more complicated and important problems on eigenvibrations of beams, plates, and shells with elastically attached loads. [ABSTRACT FROM AUTHOR]

One of the main problems in control is that the overwhelming number of physical quantities cannot be measured directly. Hence, there arise so-called inverse problems on the determination of physical quantities from the results of their manifestations. In the mechanics of a deformable solid there is a problem of obtaining material properties at all stages of deformation and especially at the overcritical stage. In this paper, we formulate and solve the inverse problem of finding the tensile diagram of a material element from the diagram of the dependence of the bending moment on the curvature of a rectangular beam under pure bending. [ABSTRACT FROM AUTHOR]

Computer simulation is widely used in the design and development of technical products. Multiscale nature of deformation and fracture of novel materials requires to use for this purpose not only the conventional finite element method but particle methods at different spatial scales as well. This paper presents a computer code aimed for discrete-continuum simulation of friction based on coupling finite elements (as a continuum method) with movable cellular automata (discrete particle method). Two computer codes based on finite elements and written in different programming languages are used: commercial and in-house. Peculiarities of the application program interfaces of the particle code for coupling with both finite element codes are described and analyzed. It is shown that the code developed takes the advantages of both cases and promises to be very efficient for simulating various contact problems including friction. [ABSTRACT FROM AUTHOR]

Multiphase machine models can be accurately designed and represented by means of MATLAB Simulink. This is because the dq-axis flux linkages and the torque response of the multiphase machines can be accurately expressed and described by means of lookup tables-based finite element method (FEM) simulations. However, the power electronic converters are easily implemented using MATLAB Simscape. Hence, the two MATLAB blocks should be connected together to provide the whole drive system. However, there will be a problem to easily connect the two MATLAB blocks directly. Consequently, this paper introduces a detailed description of the proposed interconnector that can be used to interface the two MATLAB blocks. A five-phase induction motor Simulink model connected to a five-phase voltage source inverter Simscape model will be presented to analyze and describe the implementation of the proposed interconnector. Finally, the simulation result of the five-phase squirrel cage induction motor, the five-phase voltage source inverter and the proposed interconnector are displayed. [ABSTRACT FROM AUTHOR]

The shock absorber is a part designed to smooth out the shock impulse and dissipate kinetic energy. The engine is the main power of the vehicle and the most direct reason that cause the vibration of the vehicle. If the shock absorber cannotcontrolthe vibration will make other parts of the body has seriously affect like vehicle handlingstability and shorten the vehicle's component life. The shock absorber system connects a vehicle to its wheels and contributes to the vehicle's road handling and braking for better safety and driving pleasure and offering a comfortable ride well isolated from road noise, bumps, vibrations. In this paper, the authors propose a new shock absorber design that it can smooth out or damp shock impulse, dissipate kinetic energy, and reduced amplitude of disturbances. When a vehicle is through on a level road and the wheels strike a bump, the spring is compressed. The compressed spring will attempt to return to its normal loaded length and will rebound past its normal height, causing the passenger and body vehicle to be lifted. The rebound process is repeated over and over, a little less each time, until the up-and-down movement finally stops. The design of spring in the shock absorber system is very urgent. In this project, a shock absorber is created using SolidWorks 2014. The model is also varyingdiameter and design of the spring. Structuralanalysis and modalanalysis are done on the shockabsorber by varying material for AISI 347 and ASTM A228 using ANSYS 19.1. The analysis is done by considering loads, bike weight with 2 person passengers. Static structural analysis was done to validate the strength of the materials and design. Modal analysis was done to know the displacements for different frequencies for the number of modes. Comparison is done for two materials with a varying diameter of spring to verify the best materials and design for the shock absorber. Based on the static analysis result, the safety factor for the fatigue life of the shock absorber design has been calculate d based on Goodman, Soderberg, and Gerber fatigue theories. The stresses and strains were also found to be optimum which leads to increase of structural strength of the shock absorber. [ABSTRACT FROM AUTHOR]

When calculating of the strength of elastic composite structures (bodies) using the finite element method (FEM), it is important to know the error of the approximate solution. Thus, it is necessary to build a sequence of approximate solutions, which is associated with the application of the procedure for shredding discrete models. Implementation of the shredding procedure (as part of micro-approach) for discrete models of composite bodies requires large resources of a computer, especially for discrete models with a micro-inhomogeneous structure. In this paper, we propose a method of equivalent strength conditions (MESC) for calculation of the static strength of elastic bodies with inhomogeneous regular structure, which is implemented using FEM with the use of multigrid finite elements (MgFE). Implementation of MESC is reduced to calculation on the strength of elastic isotropic homogeneous bodies using equivalent strength conditions. The advantages of MESC are that its implementation with the use of MgFE requires small computer resources and does not contain a procedure for shredding discrete models with inhomogeneous structure. Calculations of the strength of bodies with a microinhomogeneous regular structure using MESC show a high efficiency of its application. The main procedures realizing MESC are shown. [ABSTRACT FROM AUTHOR]

Tailings Storage Facilities (TSFs) is a facility needed to manage tailings storage resulting from mineral processing. Generally speaking, TSF stability analysis is conducted using the Limit Equilibrium Method (LEM) to determine the Safety Factor (FOS). Relying exclusively on LEM alone is inaccurate because it only meets the static equation and does not consider stress-strain deformation. To solve LEM's shortcomings, the Shear Reduction (SRT) Finite Element method was used to determine the stability of TSF. Performance comparison of Upstream TSF, TSF downstream, and Centerline TSF in statistical and pseudo-statistical load conditions utilizing LEMs and SRT is given in this paper. In order to calculate the probability of failure (Pf) and the reliability index (β) of each TSF, consideration of tailings behavior intrinsic, sensitivity, and probabilistic analysis in the context of Monte Carlo Simulation (MCS) and Point Estimate Method (PEM) is applied. The key factors impacting TSF stability are the base foundation and embankment friction angle, as well as embankment cohesion. Further analysis yields that Centerline TSF has a higher reliability index with a value of 0,6 in static loading and 0,46 in pseudo-static loading, lower failure probability with 18,18% in static loading 26,76% pseudo-static loading than Upstream TSF and Downstream TSF. [ABSTRACT FROM AUTHOR]

A highway is planned to be constructed in the Southern Mountains of East Java, along Serang Beach – Malang Regency. As it is located on the mountainous terrain, cut and fill works will be required to satisfy the design criteria of highway alignment, and stability of the designed cut slopes will be an important issue. This paper presents the results of engineering geological investigations for the design of cut slopes at STA.12+600 to STA. 24+700 along Serang Beach – Malang Regency using a slope stability chart. The engineering geological investigations show that highway construction is located in a hilly terrain morphology with a slope angle ranges between 0 and 41°. The highway construction area consists of slightly to perfectly weathered limestone and basalt, classified as extremely weak to moderately strong rocks. Tectonic and weathering had caused the rock masses in the research area to have relatively poor quality. No sign of groundwater level was observed down to a drilling depth of 20 to 30 m. Static slope stability analyses indicate that the slope at the STA. 13+300 can be designed to have a 58° global slope comprising an 85° individual slope of slightly weathered limestone and a 45° individual slope of perfectly weathered limestone. The slope at the STA. 16+350 can be designed to have a 68° global slope comprising a 90° individual slope of moderately to perfectly weathered basalt, while the slope at the STA. 24+125 can be designed to have a 61° global slope comprising a 90° individual slope of highly to perfectly weathered basalt. The analysis results of the slope stability chart need to be verified using a more robust method, such as the limit equilibrium or finite element method. Stabilities of the designed slopes also need to be verified under earthquake load and, therefore, further study is required [ABSTRACT FROM AUTHOR]

The compliant tristable mechanism is a structure that keeps the three stable equilibrium positions through the storage and delivers the energy during the deflections of flexible elements. The compliant inner tristable mechanism (CITM) has two bistable mechanisms connect with two mass on one side of the half model and the fixed ends inside the mechanism. This paper introduces the process of design the CITM with the numerical method. The chain beam constraint method (CBCM) is utilized to predict the nonlinear performance of the mechanism. The finite element method is implemented to compare with the numerical method. [ABSTRACT FROM AUTHOR]

In this paper, a fully adaptive 3D numerical methodology based on a tetrahedral element was proposed in order to improve the finite element simulation of any metal forming process. This automatic methodology was implemented in a computational platform which integrates a finite element solver, 3D mesh generation and a field transfer algorithm. The proposed remeshing method was developed in order to solve problems associated with the severe distortion of elements subject to large deformations, to concentrate the elements where the error is large and to coarsen the mesh where the error is small. This leads to a significant reduction in the computation times while maintaining simulation accuracy. In addition, in order to enhance the contact conditions, this method has been coupled with a specific operator to maintain the initial contact between the workpiece nodes and the rigid tool after each remeshing step. In this paper special attention is paid to the data transfer methods and the necessary adaptive remeshing steps are given. Finally, a numerical example is detailed to demonstrate the efficiency of the approach and to compare the results for the different field transfer strategies. [ABSTRACT FROM AUTHOR]

The work presented here is part of European project "FibreMap", which aims at the development of an automatic quality control and feedback mechanism to improve draping of carbon fibres on complex parts. The technology that is being developed in the project include a sensor system for robust detection of fibre orientation combined with a robotic system to scan complex parts. This paper focus on a comparison procedure made to compare experimental fibre orientation with finite element simulations results. First comparison results will be shown on a complex part chosen for the project. [ABSTRACT FROM AUTHOR]

The paper describes damage-plasticity model for the modelling of the host rock environment of a nuclear waste repository. Radioactive Waste Repository Authority in Czech Republic assumes the repository to be in a granite rock mass which exhibit anisotropic behaviour where the strength in tension is lower than in compression. In order to describe this phenomenon, the damage-plasticity model is formulated with the help of the Drucker-Prager yield criterion which can be set to capture the compression behaviour while the tensile stress states is described with the help of scalar isotropic damage model. The concept of damage-plasticity model was implemented in the SIFEL finite element code and consequently, the code was used for the simulation of the Äspö Pillar Stability Experiment (APSE) which was performed in order to determine yielding strength under various conditions in similar granite rocks as in Czech Republic. The results from the performed analysis are presented and discussed in the paper. [ABSTRACT FROM AUTHOR]

In this paper, a numerical solution of WFNDEC 2015 eddy current benchmark is presented. In particular, the Surface Integral Equation (SIE) method has been employed for numerically solving the benchmark problem. The SIE method represent an effective and efficient alternative to standard numerical solver like Finite Element Method (FEM) when electromagnetic fields need to be calculated in problems involving homogeneous media. The formulation of SIE method allows to properly solve the electromagnetic problem by meshing the surface of the media instead to the complete media volume as done in FEM. The surface meshing enables to describe the problem with a smaller number of unknowns with respect to FEM. This property is directly translated in an obvious gain in terms of CPU time efficiency. [ABSTRACT FROM AUTHOR]

Our existing Ultrasonic Broken Rail Detection system detects complete breaks and primarily uses a propagating mode with energy concentrated in the head of the rail. Previous experimental studies have demonstrated that a mode with energy concentrated in the head of the rail, is capable of detecting weld reflections at long distances. Exploiting a mode with energy concentrated in the web of the rail would allow us to effectively detect defects in the web of the rail and could also help to distinguish between reflections from welds and cracks. In this paper, we will demonstrate the analysis of a piezoelectric transducer attached to the rail web. The forced response at different frequencies is computed by the Semi-Analytical Finite Element (SAFE) method and compared to a full three-dimensional finite element method using ABAQUS. The SAFE method only requires the rail track cross-section to be meshed using two-dimensional elements. The ABAQUS model in turn requires a full three-dimensional discretisation of the rail track. The SAFE approach can yield poor predictions at cut-on frequencies associated with other modes in the rail. Problematic frequencies are identified and a suitable frequency range identified for transducer design. The forced response results of the two methods were found to be in good agreement with each other. We then use a previously developed SAFE-3D method to analyse a practical transducer over the selected frequency range. The results obtained from the SAFE-3D method are in good agreement with experimental measurements. [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]