Finite Element Analysis Solver Research Articles

Topology optimization with the redesigned suspension system of the internal combustion vehicle converted to an electrical vehicle

Abstract In this paper, the topology optimization of lower wishbone for a passenger car which is the converted of an internal combustion engine vehicle to an electrical vehicle was presented. On the other hand, the need to study on a suspension system arose for electrical car that was redesigned. In study, topology optimization of the structural design of the lower wishbone to be used in the front suspension was carried out by Finite Element Analysis (FEA) Method. For this purpose, firstly, the suspension spring curves and damper curves that will improve the handling, ride and comfort behaviour of the vehicle were determined, suspension system was modelled with the Multi Body Dynamics (MBD) approach. Hardpoints is necessary for vehicle dynamics and that is also an input for FEA were obtained from new suspension system via MBD analysis. In the second step, The preliminary design of the lower wishbone was created, taking into account together with the positions of the wheel drive shaft, suspension spring and brake system structural elements according to hardpoints. After designing the structure suitable for the joint types, initial design was studied on the remaining region that is for weight reduction region except the joint connection surfaces. Then, topology optimization was applied to the preliminary design for the selected load types that is come from MBD analysis. Thus, the excess volume on the preliminary design was determined for each load type. In the last stage, the results of topology optimization analysis were evaluated to reach out target weight and the producible design of the wishbone was made. Finally, Finite Element Analysis were applied to the final design for validation purposes within topology optimization work was done with the forces coming from Multi Body Dynamics. After statically solved Finite Element Analysis, a modal neutral file(.mnf) was created via FEA solver and was integrated to Adams Car as a flexbody. Flexbody was attahced to the other parts which are rigid bodies like nuckle according to Multi Body Dynamics approach. Dynamics durability cases was carried out via Adams Car. Stress results was compared to FEA results and evaluated depends on yield stress. Study results shows that the new design is lighter and competitive design and also safe in dynamics analysis for redesigned passenger car.

Numerical Modelling and Simulation for Sliding Wear Effect with Microstructural Evolution of Sputtered Titanium Carbide Thin Film on Metallic Materials

Titanium carbide materials are introduced into manufacturing industries for the reinforcement and surface protection of base materials due to their substantial ability to withstand severe environments, which include sliding wear, corrosion, and mechanical failures. A thin film of titanium carbide (TiC) is coated onto brass and copper substrates using the radio frequency magnetron sputtering (RFMS) deposition method. The coating process is carried out at constant processing parameters, which include a sputtering power of 200 W, a temperature of 80 °C, a deposition time of 180 min, and an argon (Ar) gas flow rate at 10 standard cubic centimetres per minute (SCCM). The coating, together with the base materials, is modelled and its behaviours are simulated using ANSYS Workbench R19.2 Academic, supported by Mechanical APDL solver for nonlinear finite element analysis (FEA). The deformation, equivalent stress–strain characteristics, and elastic–plastic properties of the coating are determined at applied loads of 60 N and 25 N and coefficients of friction (CoF) of 0.25 and 0.38 for the thin film deposition on brass and copper substrates. The sliding distance and the speed of the alloy steel ball used during the sliding wear operation are found to be 3 mm and 4 mm/s, respectively. The sliding wear modelling and simulation process are, however, designed for the ball-on-flat (BoF) wear technique with a dry sliding approach. Therefore, BoF wear simulations are also performed on titanium carbide–brass (TiC-Br) and titanium carbide–copper (TiC-Cu) conjugates for the evaluation of surface engineering applications such as cutting tools and in automotive, aerospace, thermomechanical, and biomedical fields. The ball used for the FEA wear simulation is made from alloy steel material (AISI 52100) with a radius of 3.175 mm.

Viability of COMSOL within the silencer selection process

Silencer selection has long been a burdensome, and occasionally iterative process. It is typically done based on tested sound attenuation values obtained using large facilities and costly equipment - making the process time-consuming and unsustainable. Fortunately, Finite Element Analysis (FEA) continues to become a more viable intermediary step between design and construction. COMSOL Multiphysics(r) is an FEA solver and simulation software. COMSOL's acoustics module can determine full octave decibel values of Transmission Loss.This paper goes through parameters and model setup in the COMSOL environment as well as the practicality and convenience of using such a software. It also investigates the reliability of such methods of acoustic analysis compared to empirical data, where it may fall short, and identifies areas in need of more analysis.

An experimental and numerical study on the behaviors of adhesively-bonded steel double-hat section components under axial impact loading

A significant consideration in the deployment of adhesively-bonded joints in applications such as automotive body structures is their performance under impact loading. Due to the distinct behaviors of an epoxy-based structural adhesive under normal and shear loads combined with its propensity to undergo brittle fracture in cohesion and adhesion, special care needs to be taken in the constitutive modeling of such an adhesive as traditional Von Mises type yielding and elastoplastic material behavior do not seem to be applicable. In the current study, to start with, experimental load-displacement behaviors till failure of single lap shear and T-peel joints with steel substrates are predicted with the aid of a cohesive zone material model using LS-DYNA, an explicit nonlinear finite element analysis solver. With confidence established on cohesive zone modeling of the joints mentioned, the procedure is extended to robust prediction of the load-displacement responses and deformed shapes of steel double-hat section components subjected to axial impact loading. Three variants of steel hat section components have been considered from the viewpoint of joining of flanges with conventional discrete spot-welds, only continuous adhesive bonding, and a hybrid configuration with a combination of adhesive bonding and sparse spot-welds. The study reported here provides insights into mechanical behaviors of adhesively-bonded steel double-hat sections under impact loading, and demonstrates an efficient finite element modeling approach for adhesively-bonded steel hat sections using cohesive zone elements with fracture mechanics-based criteria for failure.

Computational Acceleration of Topology Optimization Using Deep Learning

Topology optimization is a computationally expensive process, especially when complicated designs are studied, and this is mainly due to its finite element analysis and iterative solvers incorporated into the algorithm. In the current work, we investigated the application of deep learning methods to computationally accelerate topology optimization. We tested and comparatively analyzed three types of improved neural network models using three different structured datasets and achieved satisfactory results that allowed for the generation of topology optimized structures in 2D and 3D domains. The results of the studies show that the improved Res-U-Net and U-Net are reliable and effective methods among deep learning approaches for the computational acceleration of topology optimization problems. Moreover, based on the results, it is evaluated that Res-U-Net gives better results than U-Net for higher iterations. We also showed that the proposed CNN method is highly accurate and required much less training time compared to existing methods.

Acceleration of structural topology optimization using symmetric element-by-element strategy for unstructured meshes on GPU

PurposeStructural topology optimization is computationally expensive due to the involvement of high-resolution mesh and repetitive use of finite element analysis (FEA) for computing the structural response. Since FEA consumes most of the computational time in each optimization iteration, a novel GPU-based parallel strategy for FEA is presented and applied to the large-scale structural topology optimization of 3D continuum structures.Design/methodology/approachA matrix-free solver based on preconditioned conjugate gradient (PCG) method is proposed to minimize the computational time associated with solution of linear system of equations in FEA. The proposed solver uses an innovative strategy to utilize only symmetric half of elemental stiffness matrices for implementation of the element-by-element matrix-free solver on GPU.FindingsUsing solid isotropic material with penalization (SIMP) method, the proposed matrix-free solver is tested over three 3D structural optimization problems that are discretized using all hexahedral structured and unstructured meshes. Results show that the proposed strategy demonstrates 3.1× –3.3× speedup for the FEA solver stage and overall speedup of 2.9× –3.3× over the standard element-by-element strategy on the GPU. Moreover, the proposed strategy requires almost 1.8× less GPU memory than the standard element-by-element strategy.Originality/valueThe proposed GPU-based matrix-free element-by-element solver takes a more general approach to the symmetry concept than previous works. It stores only symmetric half of the elemental matrices in memory and performs matrix-free sparse matrix-vector multiplication (SpMV) without any inter-thread communication. A customized data storage format is also proposed to store and access only symmetric half of elemental stiffness matrices for coalesced read and write operations on GPU over the unstructured mesh.

Physics Informed Neural Networks for Electromagnetic Analysis

Deep learning has achieved remarkable success in diverse applications; however, its use in solving partial differential equations (PDEs) has emerged only recently. Here, we present a feasibility study of applying physics-informed deep learning methods for solving PDEs related to the physical laws of electromagnetics. The methodology uses automatic differentiation, and the loss function is formulated based on the underlying PDE and boundary conditions. The feasibility of the method is shown using three electromagnetic problems of varying complexity and the results show close agreement with the ground truth from a finite-element analysis solver. The application of transfer learning is also explored and results in faster training. Furthermore, a hybrid approach involving physics-based governing equations and labeled data is also introduced to improve the accuracy of the results.

(Digital Presentation) Numerical Characterization of Physical Properties of Microstructures in Lithium-Ion Batteries

In this paper, we present calculations of some of the key physical properties of microstructures of electrodes and separators present in lithium-ion batteries with porous electrode architectures. We analyze three-dimensional models of public domain real commercial porous anodes, cathodes and polyethylene (PE) separator, in order to characterize some of their microstructural properties. First, a pore space analysis of the binarized microstructure reveals the location and distribution of pores of various sizes, the overall porosity distribution and connectivity. Next, diffusion simulations using a random-walk method are performed to compute and accurately validate in-plane and through-plane effective transport coefficients and tortuosities, for different electrodes and calendaring levels. Single phase fluid flow simulations are performed using a commercial Lattice Boltzmann Method (LBM) solver to accurately validate the permeability of the microstructures. Next, multi-phase fluid flow simulations are done using this LBM solver to simulate the electrolyte in-filling process for various solvents. We predict that in-filling process may result in residual gas bubbles, which effect is shown in subsequent diffusion simulations to reduce the effective transport. The calculated McMillan numbers after in-filling show good agreement with experimental results. Next, we simulate the mechanical deformation of these microstructures under compressive strain using a finite element analysis (FEA) solver. This work illustrates how the use of multi-physics simulation tools can help to design these microstructures to satisfy the mechanical and electrochemical properties required of them. Figure 1

Topology and size optimization for X-bracing system of nonlinear inelastic space steel frames

In this article, a Python-programmed advanced design paradigm is firstly introduced to topology and size optimization of the X-bracing system of nonlinear inelastic space steel frames. For that purpose, an advanced analysis method considering both geometric and material nonlinearities is utilized as an effective finite element analysis (FEA) solver. In which, X-bracing members are modeled by truss elements, while the beam and column members are simulated by beam-column ones. The bracing members’ cross-sectional area and their position are respectively treated as discrete size and topology design variables. The problem aims to minimize the weight of X-bracing system so that the constraints on the strength, inter-story drift and maximum displacement are satisfied. An adaptive hybrid evolutionary firefly algorithm (AHEFA) is employed as an optimizer. Numerical examples are exhibited to illustrate the powerful ability of the present methodology.

Multi-material topology optimization considering natural frequency constraint

PurposeThe purpose of this paper is to propose an effective and efficient numerical method that can consider natural frequency in multi-material topology optimization (MMTO) and which is scalable for complex three-dimensional (3D) problems.Design/methodology/approachThe optimization algorithm is developed by combining custom FORTRAN code for MMTO with the open-source software Mystran, which is used as a finite element analysis (FEA) solver. The proposed algorithm allows the designer to shift the fundamental frequency of the design beyond a defined frequency spectrum from the initial designing phase. The methodology is formulated in a smooth and differentiable manner, with the sensitivity expressions, required by gradient-based optimization solvers, presented.FindingsNatural frequency constraint has been successfully implemented into MMTO. The use of open-source software Mystran as an FEA solver in the algorithm provides ability to solve complex problems. Mystran offers powerful built-in functions for eigenvalue extraction using methods like Givens, modified Givens, inverse power and the Lanczos method, which provide the ability to solve complex models. The algorithm is successfully able to solve both two- and three-material MMTO jobs for two-dimensional and 3D geometries.Originality/valueNatural frequency constraint consideration into topology optimization is very challenging due to three common issues: localized eigenmodes, mode switching and high computational cost. The proposed algorithm addresses these inherent issues, implements natural frequency constraint to MMTO and solves for complex models, which is hardly possible using conventional methods.

Integral Design of a Turbocharger for Internal Engine Energy Saving: Centrifugal Compressor Design

Abstract Energy savings and emission reductions are essential for internal engines. Turbocharger is critical for engine system performance and emission. In this study, the engine simulation program was used to systematically optimize the engine turbocharger system performance. The velocity ratio concept was used in the engine simulation program to consider the performance impacts of the wheel diameter ratio between compressor and turbine. An integral consideration for both compressor and turbine was proposed to design the new turbocharger. An optimization process was used to design the compressor. The performance and mechanical integrity assessments for final designs by using computational fluid dynamics (CFD) and finite element analysis (FEA) solvers were reported in this paper. The optimized compressor wheel has some distiguished features comparing with conventional designs. In this design, the splitter is not located at the middle between the two main blades; the compressor wheel exit diameter at shroud is larger than exit diamerer at the hub. The new compressor was tested on both gas stand and engine. The numerical results are fairly agreed with gas stand tests. The tests showed about 1.2% of the engine BSFC reduction without sacrificing the emission and cost. This study demonstrated that a systematic method in simulation and a compressor design optimization process could optimize the engine system and improve the engine performance.

Optimal finite element modeling of filament wound CFRP tubes

The complexity of fiber patterns within the layers of a Carbon Fiber Reinforced Polymer (CFRP) composite made with the filament winding technique has an active effect on the mechanical properties of the layer and respectively of the whole structure. While the approximation of mechanical properties in classic laminated composites is a relatively well-researched subject, there is a lack of information on filament wound cylindrical composites. Due to its material variability, filament wound CFRPs require certification results through numerical - experimental validation. Thus, in this work, an optimal modeling procedure of filament wound CFRP tubes is presented. The main goal is to acquire the lamina mechanical properties that could reliably be used in further finite element analyses with implications in critical practical applications with linear and nonlinear characteristics. At first, a homogenization method is applied to obtain the nominal values of layer properties. Next, a simple tensile test, conforming to ASTM 3039 standards, was repeatedly carried out using a representative sample of CFRP specimens, measuring experimental strain data. A stochastic state-of-the-art single objective optimization algorithm coupled to a robust finite element analysis solver is employed in order to finely tune the lamina material parameters minimizing the residual between experimental measurements and numerical predictions. Lastly, three tensile-based validation tests of stepwise difficulty and varying layer orientation, thickness, internal diameter, width and loading conditions are carried out, efficiently confirming the reliability of the characterized lamina material properties. Comparison of experimentally measured and optimal model’s numerically predicted strain response time histories in both linear elastic deformations as well as in nonlinear large deformations under progressive failure response strongly supported the efficacy and effectiveness of the proposed methodology.

階層型領域分割法による電磁界解析における四倍精度演算の検討

This paper deals with a finite element analysis (FEA) of an electromagnetic problem with a quadruple precision floating point number. A Conjugate Gradient (CG) method for real symmetric matrices and a Conjugate Orthogonal Conjugate Gradient (COCG) method for complex symmetric matrices are implemented in the quadruple precision. Then, an FEA solver with the quadruple precision arithmetic for the electromagnetic problem is implemented by the C language. As a result, the convergence of the iterative method is improved, and the minimum residual norm is reduced by approximately three orders of magnitude.

Graphics Processing Unit-Based Element-by-Element Strategies for Accelerating Topology Optimization of Three-Dimensional Continuum Structures Using Unstructured All-Hexahedral Mesh

Abstract Topology optimization has been successful in generating optimal topologies of various structures arising in real-world applications. Since these applications can have complex and large domains, topology optimization suffers from a high computational cost because of the use of unstructured meshes for discretization of these domains and their finite element analysis (FEA). This article addresses this challenge by developing three graphics processing unit (GPU)-based element-by-element strategies targeting unstructured all-hexahedral mesh for the matrix-free precondition conjugate gradient (PCG) finite element solver. These strategies mainly perform sparse matrix multiplication (SpMV) arising with the FEA solver by allocating more compute threads of GPU per element. Moreover, the strategies are developed to use shared memory of GPU for efficient memory transactions. The proposed strategies are tested with solid isotropic material with penalization (SIMP) method on four examples of 3D structural topology optimization. Results demonstrate that the proposed strategies achieve speedup up to 8.2 × over the standard GPU-based SpMV strategies from the literature.

Exploring simplification methods in reducing simulation time for drop test analysis

- Automotive electronics can produce an unprecedented level of passenger comfort and optimized performance of engine and components. However, the increasing intricacy of these electronic devices makes them more susceptible to damage due to thermal loads, mechanical drops, and engine vibrations. While physical handling of automotive components is comparatively rare, the weight and complexity of specific components such as the ECU, power module, and sensor modules, makes any drop functionally fatal. Simulation approach is considered to be essential in solving these problems by minimizing costs and effort. This paper attempts to solve the issue of mechanical drops using an explicit dynamics finite element analysis solver. Moreover, simplification methods are applied to further minimize solution costs.

Experimental and simulation investigation on BVID and CAI behaviors of CFRP laminates manufactured by RTM technology

Purpose The purpose of this paper is to synthetically investigate the impact damage responses of carbon fiber reinforced polymer (CFRP) and its influence on the compression mechanical responses of CFRP laminates, including damage distribution, residual compressive strength and fracture morphology. Design/methodology/approach A progressive damage simulation model is developed to analyze the complicated damage responses of CFRP laminates that are manufactured by resin transfer method (RTM) technology. Based on the ABAQUS/explicit finite element analysis solver, a VUMAT code is proposed to descript the composite materials’ damage behaviors under both impact and compression load. Adopting this proposed model, the primary mechanical indicators of four groups’ 5284RTM/U3160 CFRP laminates with different stacking sequences are predicted. Moreover, impact and compression after impact tests are conducted to verify the accuracy of simulation results. Findings Both simulation and experimental results show that the impact damage with low visible detectability can significantly reduce composites’ compressive strength. For all four groups’ composite laminates, the residual strength ratio is around 35% or even lower. The kernel impact damage near the plates’ geometric center promotes the degradation process of local materials and finally leads to the early occurrence of mechanical fracture. In addition, the impact damage projection area is not sensitive to the parameters of stacking sequences, while the residual compression strength is proportional to the number of 0-degree layers within whole laminates. Originality/value This study helps to understand the effect of an impact event on CFRP laminates’ compressive bearing capacity and provides a numerical method in simulating the damage responses under both impact and compression load.

Slot Filling Factor Calculation and Electromagnetic Performance of Single Phase Electrically Excited Flux Switching Motors

For variable speed applications, flux controlling capability of electrically excited flux switching motors (EEFSMs) attract researchers’ attention. However, low copper slot filling factor of the EEFSM with standard stator slot vitiates the electromagnetic performance and efficiency. This paper has proposed a new Octane Modular Stator (OMS) EEFSM model that has pentagonal stator slot and high copper slot filling factor. Copper slot filling factor is deliberated analytically for the proposed model and designs with standard stator slots, i.e., trapezoidal and rectangular. Electromagnetic performance of the OMS, Rectangular Stator Slot (RSS) and Trapezoidal Stator Slot (TSS) EEFSM designs are evaluated by finite element analysis (FEA) through JMAG v18.1 FEA solver. The proposed OMS EEFSM model has 9% higher copper slot filling factor in comparison with standard stator slots designs under same geometric parameters. The high copper slot filling factor of the proposed OMS EEFSM model has improved performance in term of low electric and magnetic loading.

Aerodynamic Performance of a Flapping Wing Inspired by Bats

Bio-inspiration is a design method where natural observation was used to solve a mechanical problem. In this study, a bio-inspiration meth-od was used to design a flapping wing for a Micro Air Vehicle (MAV) that is inspired by bat wings. The objective of this study is to study the aerodynamic performance of a flapping wing based on bat wings at different angles of attack. This is done using Computational Fluid Dynamics (CFD) simulation where the aerodynamic performance a wing derived from a natural bat wing shape was studied. The wing was generated by tracing the wing shape of a bat wing and the shape was generalized to produce the wing shape. In the simulation, a 2-way Fluid Structure Interaction (FSI) method was used where a Finite Element Analysis (FEA) solver was coupled with a CFD solver to simulate the wing during flapping flight. The flight condition was set at 1 m/s flight speed at a flapping frequency of 2.5Hz. From the results, it was shown that the wing has a zero-lift angle at 0o and a stall angle at 16o. It is also shown that the wing has a minimum drag angle at 3o and a maximum aerodynamic efficiency at angle of attack 12o.

Failure analysis of fretting fracture in frame rails of heavy duty trucks – Case study

This paper analyzed fatigue fracture of a frame rail during accelerated endurance test of a heavy duty truck. This fracture was noted in an area of high shear stresses where contact and fretting fatigue was suspected. A cross section through the fracture initiation site showed areas of surface contact wear in the microstructure. Fretting wear resulted in crack initiation and propagated to form a through crack under reverse bending fatigue crack growth mechanism. A combination of crack growth simulation tool (FRANC3D) and finite element analysis solver (MSC NASTRAN) was used and automated to handle multiple crack growth iterations. The simulation results obtained showed good correlation to failure crack path and cycles to failure. These simulation results were also used to understand the root cause of failure, identify critical parameters causing failure and recommend design modifications to prevent fretting fatigue in frame of heavy duty trucks. A modified design using the proposed simulation methodology was identified and was shown to provide improved frame durability.

Application In Communication Equipments Antiseismic Time History Analysis Based on Advanced Mass Scaling

RADIOSS is a powerful and stable explicit non-linear finite element analysis (FEA) solver in Altair HyperWorks. In this paper, the seismic time history analysis of communication equipment based on RADIOSS solver was taken as the research object. In the numerical simulation, three methods were applied in the computational efficiency enhancement: the non-timestep control method, the traditional mass scaling technology, and the advanced mass scaling technology (AMS). Calculations prove that the AMS technology in RADIOSS can not only improve the solution efficiency, but also guarante the calculation accuracy in antiseismic time history analysis.