Finite Element Numerical Simulation Research Articles

The Formation and Modification of the Arcuate Tectonic Belt in the Northeastern Tibetan Plateau: Insight from Three-Dimensional Finite Element Numerical Simulation

The Formation and Modification of the Arcuate Tectonic Belt in the Northeastern Tibetan Plateau: Insight from Three-Dimensional Finite Element Numerical Simulation

Structural design and safety performance of a novel high-strength steel lightweight guardrail.

Highway guardrails are critical safety infrastructure along roadways, designed to redirect vehicles back into their lanes and facilitate a gradual deceleration to a complete stop. Traditional highway steel guardrails exhibit significant limitations, including inadequate energy absorption, susceptibility to corrosion, and an increased risk of vehicles leaving the roadway during severe collisions. Furthermore, the production and transportation of these guardrails contribute to substantial carbon emissions and environmental pollution. This study presents an optimization of the cross-sectional shape of the conventional corrugated beam guardrail, proposing a lightweight structure that incorporates high yield strength steel plate HR700F to enhance energy absorption capacity. The safety performance of the proposed guardrail is rigorously assessed through finite element numerical simulations and full-scale collision tests with real vehicles. Key performance indicators-such as the maximum dynamic lateral deflection of the guardrail, occupant impact velocity, and acceleration-are utilized to evaluate the energy absorption and protective efficacy of the structure. Results indicate that the optimized guardrail not only meets SB-level safety standards but also demonstrates superior anti-collision performance and effective energy absorption and buffering characteristics. The proposed design achieves a reduction in beam plate thickness by 1.3 mm, resulting in a lightweight structure with a weight reduction of up to 44%, thereby supporting the advancement of low-carbon, environmentally sustainable transportation solutions.

Study on the law of air leakage in goaf under the influence of double-series coal seam mining.

In order to solve the engineering problem of a large amount of wind leakage in the 8106 comprehensive mining working face of the Carboniferous System under the influence of overlapping mining of two coal seams in Yongdingzhuang Mine, Datong Mining Area, this paper utilizes finite element numerical simulation software to study the wind leakage characteristics of the 8106 working face and the distribution range of the spontaneous combustion "three zones" of the mining area. The results show that, under the condition of external air leakage, the internal pressure of the goaf is greater than the external pressure, the upper pressure is greater than the lower pressure, and the seepage direction is from the top down and from the inside out. Under the condition of no external air leakage, the air leakage source is mainly concentrated in the air inlet lane. When there is no external air leakage, the goaf oxidation zone is evenly distributed with a width of 70m. When there is external air leakage, the width of oxidation zone in goaf is between 70m and 150m. With the increase of external air leakage, the area and width of oxidation zone on both sides of the inlet and return air duct become larger, which leads to the increase of coal spontaneous combustion risk in coal mining airspace. The research results of this paper have theoretical guidance for air leakage monitoring and fire prevention in goaf.

Effect of Cold Deformation on the Microstructural and Property Uniformity of Al2O3/Cu Composites.

Copper matrix composites (Cu-MCs) have garnered significant attention due to their exceptional electrical, wear-resistant, and mechanical properties. Among them, Al2O3/Cu composites, reinforced with Al2O3, are a focal point in the field of high-strength, high-conductivity copper alloys, owing to their high strength, excellent electrical conductivity, and superior resistance to high-temperature softening. Cold deformation is an effective method for enhancing the mechanical properties of Al2O3/Cu composites. However, during cold deformation of large-cross-sectional Al2O3/Cu composites, the inhomogeneity in microstructure and properties induced by varying stress states cannot be overlooked. In this study, cold deformation of 1.12 wt% Al2O3/Cu large-cross-sectional composites was performed using a rolling process, coupled with finite element numerical simulations, to investigate the distribution characteristics of microstructure and properties during the rolling process. The results indicate that under cold deformation, the hardness of the material increases linearly from the surface layer to the core, while the change in electrical conductivity is minimal. The increase in hardness is closely related to variations in dislocation density and grain size, with dislocation density being the dominant strengthening mechanism. Quantitative analysis reveals that strain inhomogeneity during cold deformation is the primary cause of microstructural differences, leading to variations in mechanical properties at different positions. This study provides a theoretical basis for understanding the inhomogeneity of cold deformation in large-sized Al2O3/Cu composites and for controlling their microstructure-property relationships.

Prediction of Mechanical Properties and Fracture Behavior of TC17 Linear Friction Welded Joint Based on Finite Element Simulation.

TC17 titanium alloy is widely used in the aviation industry for dual-performance blades, and linear friction welding (LFW) is a key technology for its manufacturing and repair. However, accurate evaluation of the mechanical properties of TC17-LFW joints and research on their joint fracture behavior are still not clear. Therefore, this paper used the finite element numerical simulation method (FEM) to investigate the mechanical behavior of the TC17-LFW joint with a complex micro-structure during the tensile processing, and predicted its mechanical properties and fracture behavior. The results indicate that the simulated elastic modulus of the joint is 108.5 GPa, the yield strength is 1023.2 MPa, the tensile strength is 1067.5 MPa, and the elongation is 1.98%. The deviations from measured results between simulated results are less than 2%. The stress and strain field studies during the processing show that the material located at the upper and lower edges of the joint in the WZ experiences stress and strain concentration, followed by the extending of the stress and strain concentration zone toward the center of the WZ. And finally, the strain concentration zone covered the entire WZ. The fracture behavior studies show that the material necking occurs in the TMAZ of TC17(α + β) and WZ, while cracks first appear in the WZ. Subsequently, joint cracks propagate along the TC17(α + β) side of the WZ until fracture occurs. There are obvious tearing edges formed by the partial tearing of the WZ structure in the simulated fracture surface, and there are fracture surfaces with different height differences at the center of the joint crack, indicating that the joint has mixed fracture characteristics.

Impact of joint boundary geometry on the mechanical behavior of variable‐diameter bistable composite structures

AbstractVariable‐diameter bistable composite structures with joint boundaries have significant potential for application in engineering, particularly in aerospace systems. This study focuses on analyzing the effects of joint boundary geometry, specifically the parameters of wavy boundaries, on the bending stiffness of these structures. To simplify the analysis, a beam model was established, with the joint boundary approximated as a rotational spring characterized by rotational stiffness. Using this model, the influences of wavy boundary geometric parameters, specifically the amplitude and wavelength, on the bending stiffness were systematically analyzed and compared against those of structures with straight joint boundaries. The findings indicate that larger amplitudes and suitable wavelengths can significantly enhance the bending stiffness, thereby improving the overall mechanical performance of the structure. The accuracy of the theoretical model was further verified through finite element numerical simulations. The experimental results demonstrated the practical influence of the wavy joint boundary parameters on the bending stiffness, underscoring the importance of the wavy boundary design in optimizing the performance of bistable structures, particularly in aerospace applications where an increased bending stiffness can contribute to lightweight and flexible structural designs. This work provides a theoretical foundation and practical guidance for the optimal design of variable‐diameter bistable composite structures.Highlights Investigated the impact of wavy spliced boundaries on the bending stiffness of bistable structures. A beam model for predicting the effect of the joint shape on the bending performance was developed. Compared with straight‐edge joints, irregularly spliced joints increased the peak bending load by 22%. The irregular joints had an MFS of 0.45, three times greater than that of the straight‐edge joints.

Three-Dimensional Numerical Simulation of Controlled-Source Electromagnetic Method Based on Third-Type Boundary Condition

Controlled-source electromagnetic method (CSEM), as a significant geophysical exploration technique, plays a crucial role in imaging subsurface structures. To enhance the accuracy and efficiency of CSEM simulations, this paper introduces a 3D unstructured vector finite element numerical simulation method based on the third-type boundary condition. Vector finite elements are particularly suitable for handling discontinuities in the electric field normal. They automatically satisfy tangential field continuity and zero-divergence requirements, providing a solid foundation for forward modeling in the CSEM. The adoption of the third-type boundary condition aims to reduce computational scale while ensuring higher simulation accuracy. Using this method, we conducted detailed numerical simulations on various models, including layered models, single-anomaly models, composite-anomaly models, and layered-anomaly models. The experimental results demonstrate that the algorithm accurately reproduces the electromagnetic responses of various geological models. It also exhibits superior computational accuracy under low-frequency conditions, outperforming traditional simulation methods. In summary, the 3D unstructured vector finite element numerical simulation method proposed in this study offers an efficient and reliable solution for CSEM, which is of great significance for advancing CSEM technology, especially in inversion techniques and data interpretation. Future work will focus on further optimizing algorithm performance and exploring its application potential in complex geological environments.

Research on Three-Dimensional Resistivity Imaging for Non-Conventional Electrode Arrays in Restricted Exploration Area

The 3D resistivity imaging surveying is adept at identifying structural details at various subsurface depths, and it can acquire valuable underground information even in complex geological environments. This technique has been widely applied in fields such as geological exploration, hydrogeology, and environmental monitoring. Currently, the 3D electrical resistivity surveys in the field are primarily deployed using regular grid and equidistant electrode layouts. However, when the survey area is influenced by obstacles or when the target being investigated is particularly complex, this may hinder the deployment of the electrode array in accordance with a rectangular grid. In some instances, it may even be impossible to position the electrodes directly above the target of investigation. The only viable option is thus to place electrodes around obstacles or special targets. In view of this, this paper studied unconventional electrode arrays and inversion imaging techniques of 3D electrical resistivity surveying in confined areas. It presents the design of three electrode arrays: “□”-shaped, “U”-shaped, and “L”-shaped. Furthermore, the study explores 3D resistivity finite element numerical simulation and inversion imaging techniques based on continuous electrical media. Finally, model experiments were conducted to verify the feasibility of these three special electrode arrays. We have applied the “□”-shaped electrode array to investigate the foundation structure of an ancient pagoda in Zhejiang Province, achieving promising results. This study provides valuable reference for the research and application of special observation in 3D electrical resistivity exploration.

Shear behavior of metal plate joints of laminated bamboo lumber at different angles or sizes

ABSTRACT To determine the shear behavior and slip resistance of metal plate joints of laminated bamboo lumber (LBL), considering the influence of sizes (length and width) and angles of metal plates, 100 specimens were tested. When the angle of the metal plate is different, the force modes can be divided into three types: pure shear, shear-tension, and shear-compression modes. According to the test results, the shear-tension modes of metal plate joints have the strongest bearing capacity, followed by the pure shear mode in second place and the shear-compression mode in last. The change in the size of the joints dramatically influences the ultimate load. Based on the test, the load-slip curves of the shear metal plate connected joints of LBL were fitted by the Foschi formula, and the fitting results were in good agreement with the test results. Finally, the ultimate shear strength of LBL joints was compared with that of other wood/bamboo composites. The results show that the shear performance of metal plate joints of LBL is better than that of ordinary wood materials. The test provided a reference for the engineering structures and finite element numerical simulation analysis of metal plate connected joints of LBL.

Exploring seismic warning thresholds for vehicle-track systems through combined shaking table tests and dynamic numerical simulations

This study conducted vehicle-track shaking table model tests at the Seismic Laboratory of the China Academy of Building Research, employing both unidirectional (horizontal) and bidirectional (horizontal and vertical) seismic waves. Discussions were made on the dynamic response of the vehicle-track system and the mechanism of derailment, providing data support for the research on seismic early warning thresholds for vehicles. Additionally, three-dimensional finite element numerical simulations were performed on the vehicle-track dynamic model, successfully incorporating track irregularities into the model. In this paper, the main conclusions are as follows: The limits of the wheel load reduction rate and that of the derailment coefficient specified in China’s national standard “Code for Dynamic Performance Evaluation and Test Identification of Railway Vehicles” are conservative. The primary cause of vehicle derailment was identified as horizontal vibration of the track structure induced by seismic activity. Different seismic waves have varying effects on the dynamic response of the vehicle-track model, necessitating further research on the impact of seismic wave spectrum characteristics on vehicle safety during operation. When horizontal and vertical seismic waves are simultaneously applied, horizontal seismic waves have a greater impact on dynamic response. The numerical simulation results align well with experimental results, confirming the accuracy of the vehicle-track dynamic numerical model. It is recommended to adopt a more conservative seismic early warning threshold of 0.04 g to ensure the safety of train operation.

Natural materials modified mud mortar for rubble stone masonry: An experimental and numerical study

Rubble stone masonry is a long-standing construction. However, its binding material and mud mortar exhibit shortcomings, including low tensile and shear strength and poor water resistance. To overcome these limitations, researchers have initiated investigations into modifying mud mortar, specifically focusing on the influence of natural materials on their performance. This study used straw (0-1wt%) and starch (0-7wt%) as modifiers for mud mortar. The modified mortar underwent compression, straight shear, split tensile, water immersion, and abrasion tests to investigate its mechanical properties and water resistance. Additionally, electron microscope scanning was employed to reveal the modification mechanism of mud mortar at the microstructural level. The study results showed that 0.5wt% straw/ 5wt% starch was the optimal blended mortar. In contrast, for compressive strength, tensile strength, cohesion, and water absorption capacity, starch was better than straw, and for internal friction angle and abrasion resistance, straw was better than starch. The modification mechanisms of both were bridging and gelling effects, respectively. Lastly, finite element numerical simulations were employed in this study to analyze how modified mud mortar influences the shear performance of rubble stone masonry walls. The results demonstrated that adding both straw and starch substantially enhanced the shear strength and ductility of the walls. Specifically, the additions of 0.5wt% straw and 5wt% starch increased the shear strength by 18.12% and 9.1% and the ductility by 8.48% and 0.83%, respectively. This study significantly advances low-carbon, green buildings, and sustainable development.

Study on the propagation behavior of ablation-induced cracks in HfC-coated C/C composites by finite element numerical simulation

Study on the propagation behavior of ablation-induced cracks in HfC-coated C/C composites by finite element numerical simulation

Study on predicting plate deformation under double charges coupled loading based on GBR-RFR stacking model

Abstract In modern information warfare, quickly and accurately destroying enemy key targets is crucial. The single damage mode of traditional ammunition no longer meets the demands of complex combat environments. Therefore, it is necessary to explore the damage modes and plastic deformation of targets under double charges coupling to achieve precision strikes. This paper studies the predictive model of plate deformation under double charges coupling. A double charges synchronous explosion was used as the means of coupling shock wave loading, and double charges experiments on the damage to Q235 metal plates were conducted. Based on the experimental results, a three-dimensional finite element numerical simulation model was established and its accuracy was verified. Further simulation conditions were added, and data on the plastic deformation at the center of the metal plate under double charges synchronous loading were calculated. A predictive model for the plastic deformation at the center of the metal plate was constructed based on the GBR-RFR stacking model, thereby obtaining a predictive model for the plastic deformation at the center of the metal plate under double charges synchronous loading. Through dual-source synchronous explosion experiments and finite element numerical simulations, plastic deformation data at the center of Q235 metal plates under different loading conditions were obtained. Validation results show that the finite element simulation model can accurately predict the deformation of the plate. On this basis, the predictive model constructed based on the GBR-RFR stacking model demonstrates high prediction accuracy, providing an effective method for predicting the deformation of metal plates under double charges synchronous loading.

Simulation Study on the Damage Characteristics of Semiconductor Bridge Initiators during Penetrating Concrete

Abstract The emergence of penetrating warheads poses a great threat to thick concrete targets. Initiators play a crucial role in the reliable and effective damage of penetrating warheads. In order to study the damage characteristics of initiators in penetrating overload environments, this paper uses LS-DYNA finite element numerical simulation software to study the damage characteristics of initiators under penetrating thick concrete conditions. By comparing and analyzing the stress, overload, and structural changes of various components of semiconductor bridge initiators at different stages. The results indicate that the overload experienced by initiators is greater than that experienced by projectiles, and their overload curves are more oscillatory. The internal structure of initiators amplifies the overload, making the penetration overload environment more severe for Initiators. Predicting the vulnerable areas of semiconductor bridge initiators during penetration provides direction for the redesign and reinforcement of initiators in the future.

Research on Identification of Fire Signal of a Certain Type of Rocket

Abstract To assess the contradiction between ballistic safety and ignition reliability in traditional rocket projectile inertial initiation mechanisms, this study focuses on the recognition of graze bursting ignition signals for a specific type of rocket projectile. By utilizing a finite element numerical simulation method to model the small-angle impact of the rocket projectile on a target, the overload information can be extracted from the ignition mechanism. The accuracy of the simulation model can be validated by comparing it with data obtained from live ammunition tests. Through a series of simulations, the ignition threshold can be determined by the maximum velocity change vector within different time windows of the ignition mechanism. And the integration algorithm is used to accumulate the overload value of the ignition mechanism in the time window to judge whether the velocity change threshold is reached, and then judge whether to output the ignition signal. The algorithm verification shows that the algorithm can effectively identify the ignition signal under the set ignition threshold. This method provides a basis for recognizing the graze bursting ignition signal.

Finite Element Numerical Simulation and Repair Process of Laser Cladding Repair of Surface Cracks on Mechanical Parts.

This study focuses on the planetary gear reducer and employs ANSYS 13.0 software to perform thermo-mechanical coupled simulations for the laser cladding repair process, aiming to address gear failure caused by cracks. The optimal theoretical repair parameters were determined based on temperature and stress field analyses, and performance testing of the cladding layer was conducted to validate the feasibility of the selected parameters. The results suggest that a laser power of 140 W and a scanning speed of 8 mm/s represent the optimal theoretical parameters for the laser cladding repair of the gear workpiece. Tensile strength tests revealed that the cladding layer's maximum tensile strength reached 1312.80 MPa, which was 1.22 times higher than that of the substrate material. Additionally, the wear resistance tests indicated that the wear loss of the cladding layer under the optimized parameters reduced from 9.3 mg for the base material to 0.5 mg, demonstrating excellent wear resistance. Thus, the mechanical properties of the cladding layer were significantly enhanced compared to the base material under these theoretical process parameters.

Heat Transfer Simulation and Structural Optimization of Spiral Fin-and-Tube Heat Exchanger

The spiral fin-and-tube heat exchanger is a widely used heat transfer device in heating and cooling applications, and its performance is influenced by multiple structural parameters, including the pitch, thickness, and height of the fins, the diameter and thickness of the base tube, and the transverse and longitudinal tube spacings. This study comprehensively explores how these factors affect the heat transfer performance of the spiral fin-and-tube heat exchanger and aims to determine its optimal configuration of structural parameters. First, orthogonal experiments are arranged based on these factors to conduct the corresponding finite element numerical simulations and to determine the effects of these factors on the heat transfer and resistance performance of the spiral fin-and-tube heat exchanger. Subsequently, support vector regression (SVR) is introduced to predict the heat transfer factor and the resistance factor, with the aim of benefiting the construction of a multi-objective optimization model for optimizing the two factors simultaneously. Then, a comprehensive performance indicator is used to transform the multi-optimization problem to a single optimization problem, and the genetic algorithm is adopted to solve an optimal configuration of the heat exchanger structural parameters. Ultimately, the finite element numerical simulation is utilized to validate the accuracy of the optimization. Case studies are conducted on a specific spiral fin-and-tube heat exchanger. After the optimization, the heat transfer factor is improved by 44.44%, and the resistance factor is increased by 14.19%. However, the comprehensive performance indicator is increased by 38.79%.

Finite Element Analysis of the Structural Behavior of a Corroded Pipe Culvert

The stress analysis of buried pipe culverts is a complex task, and accurately characterizing the deterioration of mechanical properties caused by corrosion poses significant challenges. In this study, the finite element analysis software PLAXIS 3D was employed to construct a numerical simulation model of a pipe culvert. By varying the stiffness and thickness of either the entire structure or specific sections, different degrees of corrosion were simulated to investigate the influence of various cross-sectional shapes on corrosion effects. Multiple experimental controls were set to analyze both the bearing capacity and deformation characteristics under different conditions. The findings reveal that different levels of corrosion have distinct impacts on the deformation behavior of pipe culverts. Overall corrosion has the most significant effect on the overall deformation, while crown and middle corrosion show a similar effect on stiffness-related deformations. In contrast, invert corrosion has minimal impact on the stiffness-related deformation. Corrosion affects circular and elliptical pipe culverts similarly. However, the circular pipe culvert is evidently influenced by overall corrosion more significantly than the elliptical ones due to the combined effects from overall and local corrosion in their deformations. Through finite element numerical simulation, it can be used as a reference for practical engineering design and construction.

Seismic performance of self-tapping bolts-octagonal core sleeve flange square steel column connection

This study proposes a fully bolted connection joint for a square steel column incorporating an octagonal core sleeve. To ensure smooth assembly of the joint at the construction site, a certain gap is maintained between the core sleeve and the square steel column. However, this gap may exert a certain influence on the seismic performance of the joint. To enhance the seismic performance of the joints, the application of self-tapping bolt technology is recommended for optimizing the design of the joints. Based on these considerations, this study designed and conducted quasi-static tests on two specimens: the self-tapping bolt-octagonal core sleeve flange square steel column connection joint (SOFC) and the traditional column-column welded connection joint (TWC). The seismic performance of the two connection joints was compared and analyzed. The test results demonstrate that the SOFC specimen achieves the seismic design goal of “strong-joints and weak-members,” with a maximum bearing capacity of −1128.17 kN·m, which represents a 11.42 % improvement over that of the TWC specimen. Furthermore, the total energy dissipation of the two specimens across all loading levels differs by 11.2 %, indicating that their seismic performance is comparable. Additionally, a finite element numerical simulation was also performed to analyze the failure mode of the SOFC model in the limit state, clarify its failure path, and verify that the use of self-tapping bolts can effectively optimize the joint force transmission and improve the seismic performance.

Machine Learning–Finite Element Mesh Optimization-Based Modeling and Prediction of Excavation-Induced Shield Tunnel Ground Settlement

Ground settlement prediction for shield construction is highly important and challenging. This study introduces a machine learning algorithm combined with finite element numerical simulation, i.e., machine learning–finite element mesh optimization. For surface subsidence prediction, 16 combination models of ANN, KNN, RF and SVR were optimized by PSO, GA, BT and BO, involving raw data preprocessing, principal component analysis, hyperparameter selection and prediction accuracy evaluation. A subway shield tunneling project was analyzed, in which the meshes of finite element numerical models were discretized into different sizes from 1.0[Formula: see text]m to 2.0[Formula: see text]m. In total, 360 sets of data points were extracted from the simulation results, including stress, strain, shield jacking force, internal friction angle, cohesion force, and settlement, of which 252 data points were used as the input parameters of machine learning model. Analysis of average error rate of finite element–machine learning coupling models showed that the finite element model had the highest accuracy of settlement prediction when the mesh size of the finite element model was 1.4[Formula: see text]m, and the GA-SVR model had the highest accuracy and generalization ability in ground settlement prediction. This study highlights the uniqueness of machine learning–finite element mesh optimization model in application.