Finite Element Method Software Research Articles

Study on finite element method coupled with genetic algorithm in optimization for temperature uniformity of hot plate welding

Aiming to improve the temperature uniformity used for hot plate welding, two optimal design methods by coupling finite element method (FEM) with genetic algorithm (GA) are put forward and implemented into FEM software through the secondary development. Taking the positions of the heating holes and the heat fluxes applying to the heating holes as the optimization variables, the minimum temperature difference on the faying surface as the optimization objective, taking advantage of the numerical calculation of steady-state heat transfer, the parametric modeling of hot plate is carried out in accordance with the developed FEM-GA coupling optimization framework. The first optimal design method adopts a two-stage sequent optimization that the optimal positions of heating holes and the heat fluxes applying to the heating holes are sequentially obtained by using the two-step FEM-GA coupling calculations. The second optimal design method optimizes these variables simultaneously. The simultaneous optimal design method is further utilized to optimize the hot plate model associated with the orthogonal heating holes. In the case of the experience-based initialization of the optimization parameters, the two-stage sequent optimal design method is capable to achieve the better temperature uniformity on the faying surfaces with the lower computation costs, as compared with the results of the simultaneous optimal design method. The FEM-GA coupling optimal design method for improving the temperature uniformity used for hot plate welding would be of great significance for the industrial application of hot plate welding.

Optimization of the finite element meshing for the fabrication of a M3x12x0.5 screw, in 3D printing

Meshing optimization in the finite element method (FEM) is key to designing mechanical components such as screws. This study focuses on the M3x12x0.5 screw, improving its performance and durability through the appropriate selection of meshing parameters. FEM software was used to analyze its behavior under different loads, comparing it with a 3D printed model. The results showed improvements in the accuracy of predictions about resistance, deformation and stress distribution, allowing the design to be optimized. This highlights the relevance of simulation tools in the development of mechanical components.

Structural Analysis of Castellated Beams with Web Openings of Different Forms using Finite Element Method

Castellated beams are increasingly important in modern structural engineering due to their enhanced strength-toweight ratio, material efficiency, and versatility in various applications. These beams, formed by cutting and reassembling standard I-beams, offer significant advantages in reducing weight while maintaining or improving structural capacity. The present research focuses on the analysis of castellated beams using Finite Element Method (FEM) software to evaluate their behavior under various loading conditions. The study employs FEM to model these beams, simulating stress distribution, deformation, and failure modes across different configurations and loading scenarios. Factors such as span length, load type, and geometric variations are considered to assess their influence on performance. The findings provide valuable insights into the optimal design and application of castellated beams, contributing to the development of lightweight, strong structures in modern construction and supporting the advancement of sustainable engineering practices

Modeling of Electric Field and Dielectrophoretic Force in a Parallel-Plate Cell Separation Device with an Electrode Lid and Analytical Formulation Using Fourier Series.

Dielectrophoresis (DEP) cell separation technology is an effective means of separating target cells which are only marginally present in a wide variety of cells. To develop highly efficient cell separation devices, detailed analysis of the nonuniform electric field's intensity distribution within the device is needed, as it affects separation performance. Here we analytically expressed the distributions of the electric field and DEP force in a parallel-plate cell separation DEP device by employing electrostatic analysis through the Fourier series method. The solution was approximated by extrapolating a novel approximate equation as a boundary condition for the potential between adjacent fingers of interdigitated electrodes and changing the underlying differential equation into a solvable form. The distributions of the potential and electric fields obtained by the analytical solution were compared with those from numerical simulations using finite element method software to verify their accuracy. As a result, it was found that the two agreed well, and the analytical solution was obtained with good accuracy. Three-dimensional fluorescence imaging analysis was performed using live non-tumorigenic human mammary (MCF10A) cells. The distribution of cell clusters adsorbed on the interdigitated electrodes was compared with the analytically obtained distribution of the DEP force, and the mechanism underlying cell adsorption on the electrode surface was discussed. Furthermore, parametric analysis using the width and spacing of these electrodes as variables revealed that spacing is crucial for determining DEP force. The results suggested that for cell separation devices using interdigitated electrodes, optimization by adjusting electrode spacing could significantly enhance device performance.

Rapid Fluid Velocity Field Prediction in Microfluidic Mixers via Nine Grid Network Model.

The rapid advancement of artificial intelligence is transforming the computer-aided design of microfluidic chips. As a key component, microfluidic mixers are widely used in bioengineering, chemical experiments, and medical diagnostics due to their efficient mixing capabilities. Traditionally, the simulation of these mixers relies on the finite element method (FEM), which, although effective, presents challenges due to its computational complexity and time-consuming nature. To address this, we propose a nine-grid network (NGN) model theory with a centrally symmetric structure.The NGN uses a symmetric structure similar to a 3 × 3 grid to partition the fluid space to be predicted. Using this theory, we developed and trained an artificial neural network (ANN) to predict the fluid dynamics within microfluidic mixers. This approach significantly reduces the time required for fluid evaluation. In this study, we designed a prototype microfluidic mixer and validated the reliability of our method by comparing it with predictions from traditional FEM software. The results show that our NGN model completes fluid predictions in just 40 s compared to approximately 10 min with FEM, with acceptable error margins. This technology achieves a 15-fold acceleration, greatly reducing the time and cost of microfluidic chip design.

Thermo-mechanical simulation of the effect of tool welding speed on butt-joint friction stir welding (FSW) of AA6061

FSW is a welding method that joins pieces of material by rotating a non-consumable pin at high speeds (RPM) while moving it along the weld joint. The combination of this rotation and movement generates heat through friction between the tool and the sheets, facilitating the welding process without the requirement for filler metal. Developed by the British Welding Institute (TWI) in 1991, FSW is celebrated for producing strong, reliable welds and is extensively used in industries such as automotive and aerospace. In these sectors, aluminum alloys are essential due to their unique set of properties, making them highly suitable for FSW applications. In FSW, welding speed refers to the linear velocity at which the tool progresses along the joint line during the welding process. This parameter plays a pivotal role in controlling heat generation, material flow, and ultimately, the quality of the weld. The quantity of heat introduced to the plates directly influences the final weld quality, as well as the residual stresses and deformation observed in the workpieces. This research examines how different welding speeds affect temperature distribution, the width of the heat-affected zone, and the Von Mises stress distribution in welded aluminum alloy 6061 sheets. The aim of this study is to gain a comprehensive understanding of how these factors interact, with the ultimate goal of contributing to the optimization of FSW parameters and improving weld quality. The analysis was performed using finite element method and ALTAIR software, providing valuable insight into the effects of welding speed variations.

The Influence of the Brace Topology on the Reliability of the Platform Jacket Structure

Platform jacket structures are offshore buildings that support oil and gas drilling activities. The jacket's structure is generally tubular steel connected between the legs and the brace. The selection of brace topology is essential to prevent the structure from failure, such as fractures. The research was carried out by modelling the brace topology and analyzed using SACS finite element method software. Analysis of the reliability of jacket structure using the Monte Carlo simulation method. The purpose of this study is to analyze the reliability of the jacket structure and determine the optimal topological clamp model for use on it. The results show that the topology X brace model has better reliability than the support topology model K and N, where the topology X brace model can withstand a maximum force of 44000 kN with a reliability index value of 3.35. In comparison, the topology K brace can withstand a working force of 35200 kN with a reliability index value of 2.94, and the topology N brace model can withstand a working force of 32000 kN with a value of reliability index of 3.02.

Direct Shear Testing Apparatus for Saturated Rock Joints

Abstract A novel shear test apparatus has been designed and built to test saturated jointed rock specimens under normal and shear loading, capable of housing seismic transducers to monitor simultaneously the mechanical and geophysical response of the rock joints during shear. The system comprises a sealed pressure chamber and a biaxial compression frame. The internal dimensions of the chamber are 177.8 mm × 228.6 mm × 381.0 mm to accommodate a rock specimen with dimensions 152.4 mm × 127.0 mm × 50.8 mm. The chamber is made of aluminum to reduce its weight and is designed to sustain a maximum chamber pressure of 10 MPa, which is considered sufficient to be able to saturate a wide number of rocks. Structural calculations of the chamber are performed with the finite element method (FEM) software, ABAQUS, with the criterion of a maximum deflection of 1 mm at maximum chamber pressure, which is small enough to prevent the loss of seal between the loading shafts and the chamber. The rocks used in the study are Indiana limestone and Sierra White granite. B-value tests conducted on cylindrical specimens of the rocks placed inside the chamber show that the back pressures required to achieve saturation are 3.5 MPa for Indiana limestone and 5.0 MPa for Sierra White granite. The chamber performance has been evaluated by comparing the changes of volume of the chamber at different pressures, measured in the laboratory, with those predicted with ABAQUS. The successful completion of a number of repeatable direct shear tests, on tensile-induced rock joints in dry and saturated conditions specimens, has further established the correctness of the chamber design and its operation.

Numerical analysis of 3D printed joint of wooden structures regarding mechanical and fatigue behaviour

This paper presents numerical models of a 3D printed plastic joint applicable to the connection of wooden structures. The research presented provides a comparison of two alternative solutions for the geometry of the joint and results from several loading schemes and boundary conditions. Included are analyses evaluating the mechanical behaviour in a simple axial tensile test, a three-point bending test and, finally, a sensitivity analysis of the location susceptible to fatigue damage. The models include a 3D printed polycarbonate joint, wooden elements and steel shear pins. The combined model allows a deeper understanding of the interactions. Finite element method (FEM) software was used to develop the numerical models and suitably defined boundary conditions, and material properties of all parts were adopted. The simulation results show that the 3D joint exhibits a high resistance to tensile loading, while in the case of three-point bending, a higher susceptibility to fracture of the printed joint is observed. The sensitivity fatigue analysis identified critical areas on the 3D printed component that need to be improved before further development. These analyses provide important information for optimizing the design of 3D printed plastic joints intended for wooden structures.

Theoretical and experimental study of a two-dimensional circular stealth acoustic lens

The detection of underwater acoustic signals is a key focus in ocean development, and acoustic metamaterials play a crucial role in achieving this goal. Pentamode metamaterials exhibit fluid-like properties, allowing for the propagation of compressional waves without shear waves. In this study, a two-dimensional circular stealth acoustic lens based on pentamode metamaterials was proposed. By applying the transformation acoustics theory, the theoretical properties of circular stealth acoustic lenses were calculated, and they were verified with Finite Element Method (FEM). A practical model was designed with pentamode metamaterials and silicone oil, and its performance was verified with FEM software. A half-model was fabricated, and underwater experiments demonstrate that it does not effectively affect the propagation state of acoustic waves. The consistency between theoretical results and experimental findings highlights practical significance and broad application prospects for the circular stealth acoustic lens in the field of acoustic detection.

Improving dynamic energy absorption performance and stability loss prediction of an all-PET sandwich structure through artificial neural networks

Abstract One key characteristic that is frequently studied in composite sandwich structure mechanics is low-velocity impact performance. Single polymer composites present higher ductility when compared to traditional glass fibre and carbon fibre reinforced plastic composites (GFRP, CFRP), which makes them strong candidates for impact energy absorption. These lightweight structures are also fully recyclable due to their all-PET constituents, an important aspect when considering possible applications. In this paper an existing second order composite SrPET and PET foam sandwich structure (self-reinforced poly-ethylene terephthalate matrix and fibre) is numerically investigated for optimal structural design configuration under out-ofplane, low velocity, dynamic loading. The study explores the parametric geometry interdependencies of the structure’s configuration with respect to its energy absorption potential. The results are then compared to the quasi-static loading performance behaviour studied by M.N. Velea et all [1]. This work provides a deeper understanding of how geometry configurations can influence energy absorption capabilities highlighting structural strengths and weaknesses while exploring non-equilateral triangle configurations. The Design Space Exploration (DSE) is carried out by using an optimization algorithm for a dynamic out of plane 3D impact simulation based on the finite element (FE) method software. The synergy between DSE and FE generates a guided simulation loop that can successfully be used to train a neural network to predict the dynamic behaviour of different geometric configurations from the exploration space. Based on the data samples obtained, an artificial neural network (ANN) is built to predict the energy absorption capacity for a given set of structural design parameters, useful in experimental validation test cases.

RESIDUAL - STRESS AND TEMPERATURE FIELDS IN SURFACE TESTING: FINITE-ELEMENT ANALYSIS

Numerous advancements have been made to treat part surfacing, however, the presence of surface imperfections resulting from finishing processes has raised concerns about their potential to serve as stress concentrators. To address this concern, the present study utilized the power of the finite element method and cutting-edge software applications. The main aim of the study is to evaluate the stress-strain condition of material surfaces post-finishing, leveraging the comprehensive capabilities offered by these software systems. A significant component of the investigation centered on the influence of non-stationary temperature fields, as monitored by dynamic thermoelements, on the stress-strain dynamics within material surfaces. Visualization techniques were employed to depict the specified field functions, revealing notable variations in temperature distribution. The findings demonstrated that the standard function identified the highest temperature area within the 3-7-4 node segment, while the alternative function pinpointed it within the 4-node segment, indicated by the red area. These outcomes highlight the valuable role of non-stationary temperature fields in balancing the mechanical and physical aspects of the finishing process. This study contributes significant insights into the post-finishing stress-strain state of material surfaces, emphasizing the potential advantages of using modern software systems for in-depth exploration.

Numerical modelling and measurement of the E-I characteristics of MgB2 wire in sub-cooled water ice

This work presents a comprehensive 3D numerical model of MgB2 multi-filamentary superconducting wires using the Finite Element Method (FEM) software, COMSOL Multiphysics® 6.0. The study aims to investigate the electro-thermal behavior of MgB2 composite wires during standard transport measurements at various initial temperatures under subcooled water ice conditions. By solving a series of partial differential equations governing heat transfer and dynamic current transport, the model provides detailed insights into the wire’s performance. The simulation results are rigorously compared with experimental E-I characteristics measured for 6-filament MgB2 wires with internal copper stabilization. This comparison validates the model and highlights its capability to predict the behavior of superconducting wires under cryogenic conditions. The findings offer valuable data on the current distribution, ohmic losses, and overall thermal stability of the composite wires, contributing to the advancement of cryogen-free superconducting technologies. This study bridges the gap in the literature regarding the electrothermal dynamics of MgB2 wires cooled by subcooled water ice, providing a foundation for further research and practical applications in high-field generation devices.

Influence of tool rotational speed in butt-joint friction stir welding (FSW): a thermo-mechanical simulation of AA6061

Friction Stir Welding (FSW) is a solid-state welding technique that involves joining two pieces of material by rotating a non-consumable pin at high RPM. This rotation generates heat through friction between the tool and the plates, enabling the welding process without the need for filler metal. Invented by the British Welding Institute (TWI) in 1991, FSW is renowned for creating strong welds and is widely used in the automotive and aerospace industries, in those industries the aluminum alloys are indispensable due to their unique combination of properties. This study focuses on how variations in rotational speed influence temperature distribution, the width of the heat-affected zone, and Von-Mises stress distribution in welded aluminum alloy 6061 sheets, this research aims to provide a comprehensive understanding of these effect, therefore the findings are expected to contribute to optimizing FSW parameters and enhancing weld quality. The analysis was conducted using the finite element method and ALTAIR software.

Investigation of the fracture characteristics of mixed-mode I/III crack by using two kinds of sandstone specimens

This study aims to identify specimens that are more suitable for examining the failure properties of I/III mixed-mode cracks under static loads. We employed single-edge notched bending (SENB) and edge-notched disc bending (ENDB) specimens, and used ABAQUS finite element method software to calculate the stress intensity factors for modes I and III at various crack inclination angles θ. Fracture toughness was tested using three-point bending experiments on two types of sandstone specimens. The evolution of mixed-mode I/III fracture morphology and failure patterns was investigated with a monocular microscope. Additionally, the evolution of the strain field and crack tip opening displacement was analyzed using the digital image correlation method. Our findings indicate that the fracture toughness of the ENDB specimens surpassed that of the SENB specimens. The effective fracture toughness of both SENB and ENDB specimens initially increased with crack inclination angle θ but then decreased. The fracture mode correlated with energy release; the energy release rate of the ENDB specimens exceeded that of the SENB specimens, making the former more brittle. For SENB specimens, crack initiation was primarily intergranular, while ENDB specimens exhibited predominantly transgranular fractures. The crack initiation moments for both specimen types increased with higher crack inclination angles. Furthermore, at the same crack inclination angle, ENDB specimens cracked earlier than SENB specimens.

Edge Detection for Molten Metal Level in Pyrometalurgical Furnaces

This report has found a prospective analytical model for an edge response of a transmit-receive eddy current coil. A probe of this design could be used to determine in real time the molten metal height and remaining wall thickness within a pyrometallurgical furnace. This work heavily uses previously published methods to find a possible expression for the change in mutual coil impedance resulting from a right-angled edge. An advancement in the method includes using the Lorentz Reciprocity relations for a transmit-receive system to calculate impedance change. Awaiting the completion of the model, an expected response has also been modelled in a finite element method software, which will be used to verify the analytical model. Also, an experiment has been designed to be able to validate both models. What remains to be completed is a successful code implementation of the mathematics, to produce results. While analytical solutions to the equations have been obtained, implementation of coded solutions remains incomplete. Some methods for improving the code will be to better condition the matrices described in the linear algebra interface between the three regions, as well as making further improvements on the root-finding code.

Improvement of electromagnetic torque of BLDC motor for electrical cutter application

As the advancement of brushless direct current (BLDC) motor is rising, it has been an advantage to use the motor for a wide range of applications. Its robustness and torque development have benefited small applications, such as the agriculture cutter. However, dropping performances of conventional BLDC are affected by the shape of the rotor that has unused magnetic flux. Therefore, this research aimed to analyze the electromagnetic torque by reducing the unused flux from an electromagnetic point of view. Two BLDC models with different slot-pole numbers and rotor types were modeled and simulated with equal permanent magnet volume, and magnetomotive force (MMF). Finite element method (FEM) software was used to compute back electromotive force (BEMF), cogging torque, electromagnetic torque, and magnetic flux density of the BLDC models. As a result, 9/8 slot-pole with zero ferromagnetic underneath the permanent magnet had the highest BEMF and torque produced compared to the conventional type, with a percentage difference of 27%. In conclusion, this research presents the motor that had an improvement of electromagnetic torque for electrical cutter application.

Application of Laminate Theory to Plate Elements Based on Absolute Nodal Coordinate Formulation

Abstract Laminated plates have a wide range of applications in engineering, and their flexibility becomes increasingly significant with the development of lightweighting technology. The absolute nodal coordinate formulation (ANCF) has emerged as a promising approach for modeling flexible multibody dynamics. However, researches on thick laminated plates with shear deformation for multi-flexible systems remains limited. To investigate the application of ANCF plate elements for laminated plates, this article introduces a new laminated plate element that considers shear deformation. We utilize the fully parameterized ANCF plate element to analyze laminated composite structures, focusing specifically on their layers in the thickness direction. By employing a structural mechanics approach, the study achieves a uniform stiffness matrix that can adapt to laminated plates with shear deformation and can be pre-computed in advance. Additionally, a summary of a thin laminated plate element is provided for comparison. Both plate elements are composed by layers, and their elastic forces and Jacobian matrices are derived using first-order shear theory and Kirchhoff's theory, respectively. The effectiveness and accuracy of the proposed elements are validated through a series of benchmark problems encompassing modal, static, and dynamic investigations. The study thoroughly analyzes the results compared with the commercial finite element method software ABAQUS and analytical approach. The findings demonstrate that the methods effectively address laminated plates.

Structural integrity assessment of an offshore platform using RB-FEA

PurposeThe paper aims to analyze the structural integrity of an existing offshore platform located in the Northern Adriatic Sea, followed by the topside decommissioning and the re-utilization of the jacket as a wind turbine support. The structural integrity assessment against the in-place and the long-term actions is accomplished by using a reduced basis finite element method (RB-FEA) software program assessing the capability of the jacket to be used as a support for wind turbines at the end of its life cycle as oil and gas (O&G) platform.Design/methodology/approachThe project starts by modeling the jacket, and subsequently, the structural analyses for the in-place loads in operative and extreme conditions are performed. Then, the fatigue analysis is carried out in order to define the cumulative damage necessary to evaluate the possibility to use the jacket as a wind turbine support.FindingsThe results show that the jacket, at the end of the service life as O&G platform, is able to withstand the loads produced by the installation of the wind turbine since the analyses are satisfied even with the conservative approach used which overestimates the thickness loss assuming a linear increasing value during the service life.Research limitations/implicationsBecause of the chosen approach, the study presents some limitations, especially concerning the real state of the platform which has been defined considering the thickness loss only. Additionally, a 1D model was used to perform the analyses, and hence, a 3D model could help in evaluating the critical points with higher precision.Practical implicationsThe assessment of the structure could be improved by modeling a digital twin of the asset allowing a real-time monitoring which, however, involves a huge amount of data to be processed, so a suitable simulation technology must be used.Originality/valueThe RB-FEA proposed by Akselos is suitable to perform the analyses speeding up the processing of the data even in real time.

In-situ analysis of cathode and anode impedances to probe the performance degradation of lithium–sulfur batteries

Improving the performance of Li-metal batteries with sulfur cathodes while maintaining high sulfur loading (>4 mg cm−2) and low electrolyte-to-sulfur ratio (<10 mg μL−1) is a significant challenge. These conditions often result in poor battery cycle life and sudden capacity failure during charge-discharge processes. To address this challenge, we investigate Li–S batteries in a three-electrode (3E) configuration, utilizing optimized materials and geometries for the reference electrode. This configuration allows us to independently track the in-situ variations in cathode and anode resistances, along with the electrode potential difference, unveiling the root causes of abrupt battery failure during cycling. Our 3E approach uncovers previously unnoticed distortion phenomena in the electrochemical impedance spectra of both the cathode and anode, providing essential indicators of imminent micro-short circuiting. Supported by simulations using the finite element method and equivalent circuit analysis software, these insights clarify that the primary reason for battery failure is the growth of Li dendrites and their subsequent contact with the cathode, rather than a sudden increase in cell impedance. By substituting traditional Li foil with a specially designed Li anode less susceptible to Li dendrite growth, we achieve reduced anode resistance and improved battery capacity and cycle life stability. This research reveals the potential of the 3E configuration for precise in-situ impedance monitoring, which is valuable for devising strategies to enhance cycle stability.