Large-scale Finite Element Analysis Research Articles

Modal analysis of honeycomb panel satellite structure based on MSC Apex

Modal analysis plays an important role in the process of Satellite structure development. In this paper, the honeycomb sandwich plate and the satellite structure are taken as the research objects, and the corresponding finite element models are established. The analysis results of the actual modeling of honeycomb plate and the equivalent modeling of sandwich sandwich plate are obtained, and the fundamental frequency deviation of the whole satellite structure is discussed when the equivalent correction coefficient γ of honeycomb plate is different. The results show that the maximum relative error of the modal frequency between the equivalent method of sandwich sandwich plate and the actual modeling is 2.8%. Therefore, the equivalent method can be applied to large-scale finite element analysis and calculation, and the calculation efficiency can be improved. When the value of γ is 0.4∼0.6, the vibration modes of the whole satellite structure are basically consistent, and the maximum fundamental frequency difference is 10%. The results can evaluate the accuracy of the sandwich sandwich plate equivalent method for satellite mechanical analysis.

Finite Element Analysis of Steel Truss Bridge Structure Based on ANSYS

With the rapid development of bridge engineering in China, steel truss bridge is widely used with many advantages such as clear force of the structure itself, easy to analyze, and low requirement for foundation. In this paper, the finite element analysis method is adopted to analyze the stress and deformation distribution of steel truss bridge on the platform of ANSYS, a large-scale finite element analysis software. In the static analysis, by applying the vehicle load, the operation mode of the structure is simulated, and the cloud diagrams of its displacement and stress are derived. The dangerous areas of the bridge are identified to provide a reference basis for the design of steel truss bridges.

A Problem-Independent Machine Learning (PIML) enhanced substructure-based approach for large-scale structural analysis and topology optimization of linear elastic structures

Structural analysis for structures composed of highly heterogeneous materials which often involves the solution of large-scale linear algebraic equations is very time-consuming even within the linear elastic regime. Furthermore, the tremendous computational cost of iterative large-scale finite element analysis also prevents the widespread use of topology optimization as a powerful design tool especially when the desired design resolution is very high. In order to break the bottleneck hindering the efficient solutions of large-scale structural analysis and design optimization problems, in the present article, a general machine learning (ML) enhanced substructure-based framework is proposed. The essential idea is resorting to the classical substructure-based finite element analysis approach and establishing an implicit mapping between the parameters characterizing the material distribution within a substructure and the corresponding condensed stiffness matrix/numerical shape functions through offline trained deep neural networks. In contrast to most of the existing ML enhanced approaches, the proposed framework is truly independent of the forms of structural geometry, boundary condition and external load, and can be applied to solve various boundary value problems governing by the same type of partial differential equation once the offline training is completed. Armed with modern artificial intelligence techniques, the proposed approach in some sense revives the classical substructure approach in finite element analysis. Compared with the traditional paradigm, it can achieve 104–105 times solution efficiency for tested large-scale examples with satisfactory accuracy. The effectiveness of the approach was also validated for the non-adjoint topology optimization problems, i.e., 3D compliant mechanism design. Finally, to demonstrate the proposed approach’s capability in dealing with extremely large-scale three-dimensional problems, a three-dimensional topology optimization problem with about 109 design variables and 3×109 degrees of freedom (Dofs) is solved on a laptop without resorting to any parallel computing techniques.

Fine-grained heterogeneous parallel direct solver for finite element problems

The improvement of computational effectiveness is a vital issue in the field of large-scale finite element analysis. The performance is fundamentally determined by the efficiency of solving sparse linear system equations using the implicit finite element method. This paper presents a direct linear solver based on heterogeneous hybrid parallel computing on CPUs and GPUs. This can efficiently utilize computing resources of multiple devices to achieve performance improvement. Initially, we partition the elimination tree into several subtrees to accomplish the task decomposition. Based on this, we build a dynamic programming mathematical model to balance the computational load of the various devices. Then, we develop a numerical decomposition strategy by combining node parallelism and tree parallelism for the CPUs. In addition, efficient numerical decomposition is achieved on the GPU through batch processing and maximizing the overlap between computations and data transfers. Numerical experiments show that, compared with MKL PARDISO, the performance of numerical factorization can be improved by up to 10 times by using CPU and dual-path GPU hybrid calculations, and the computation time of simulation can be reduced by one-third for the multicondition analysis of Body In White and by 20% for the large-scale nonlinear finite element deformation analysis.

Combined digital twin and hierarchical deep learning approach for intelligent damage identification in cable dome structure

Accurate identification of structural damage is the most critical step in structural health monitoring. Traditional damage identification strategies are easily interfered by environmental and human factors, resulting in low-accuracy of identification. In this light, a combined digital twin (DT) and hierarchical deep learning (DL) approach for intelligent damage identification in cable dome structures is proposed in this paper. Based on actual engineering cases, a DT model that accurately maps the physical structure of the cable dome is constructed using APDL based on data. A cable dome structure damage sample database is then automatically established through the large-scale finite element analysis of DT. Finally, the damage features of the data samples are extracted using the hierarchical DL framework proposed in this study. Accuracy verification based on cable force confirms that the established DT model can accurately reflect the mechanical state of the physical structure. The identification results of the trained network on a test set demonstrate that the proposed framework can intelligently identify the damage type, damage location, and damage degree in the cable dome structure with a high accuracy and strong robustness. The proposed intelligent damage identification approach is feasible and reliable and can provide a new basis for structural damage identification with broad application prospects.

A double scalar elastic damage constitutive model of ice materials

The constitutive model of material is the basis of structural analysis and is extremely important. In order to improve the analysis accuracy of the novel ice structure, a double scalar elastic damage constitutive model of ice materials including plain ice and fiber-reinforced ice (FRI) based on continuum damage theory and fracture mechanics is established in this study. The modified Ottosen equivalent strain criterion which can consider the comprehensive mechanical properties of compression, tension and shear is used as the damage initiation criterion and the internal variable of damage evolution. Based on the uniaxial compressive and tensile experiments, the two damage evolution laws of tensile and compressive damage with the modified Ottosen equivalent strain criterion as the internal variables are established. A unified weighted damage evolution function is constructed by the strain decomposition in the principal strain space. Based on the strain equivalent assumption, a complete damage constitutive model is established, which can consider the properties of ice materials at different temperatures and fiber contents. The energy regularization of crack bond model in fracture mechanics is adopted and the softening behavior of materials is described through fracture energy and stress-crack width relationship instead of the relationship between stress and strain, which solves the problem of mesh dependence in finite element analysis. The damage constitutive model is integrated into the large-scale finite element analysis software ABAQUS through the user-defined material subroutine (UMAT), and the establishment of the numerical model is realized, which can be conveniently used for numerical simulation of ice structures. Finally, the proposed damage constitutive model is evaluated according to the comparison between the results of finite element analysis and the results of uniaxial compression, uniaxial tension and four-point bending beam experiments. The results show that the damage constitutive model can well describe the stress-strain nonlinear behavior and capture the basic failure mode of ice materials. This study will lay a foundation for the refined analysis of ice structures.

Time-variant fatigue reliability assessment of rib-to-deck welded joints using ANN-based methods

Environmental corrosion and vehicle load significantly influence the fatigue damage of steel bridges. To efficiently investigate the combined effect of stochastic vehicle load and environmental corrosion on the fatigue damage of welded joints of orthotropic steel decks (OSDs), an artificial neural network (ANN) assisted assessment framework is proposed. A stochastic fatigue vehicle load model and an atmospheric corrosion model are first adopted for probabilistic modeling of stress response of rib-to-deck (RD) welded joints. To reduce the calculation cost of large-scale finite element analyses (FEA) runs in probabilistic simulation, the relation is generated between the equivalent stress range and variables (i.e., vehicle loads and corrosion depth) using ANNs. The time-variant fatigue reliability, therefore, can be calculated using Monte Carlo (MC) simulations by considering the uncertainties of variables in limit-state functions. The efficiency and feasibility of the proposed framework are demonstrated with a steel bridge. Finally, parametric studies investigate the influence of traffic volume and corrosion on the time-variant fatigue reliability of RD welded joints.

Development of Tensile Crack Model Considering Poisson’s Effect and Its Application to a Large-Scale Finite Element Analysis of an RC Structure

Development of Tensile Crack Model Considering Poisson’s Effect and Its Application to a Large-Scale Finite Element Analysis of an RC Structure

Experimental and Numerical Study of the Dynamic Response of XCC Pile–Raft Foundation under High-Speed Train Loads

A series of dynamic large-scale model tests and three-dimensional finite element analyses were conducted to investigate the dynamic response of track embankment and XCC pile-raft composite foundation in soft soil for a ballastless high-speed railway under moving train loads. The results indicate that the vibration velocity obtained from the FE numerical simulation agrees well with that from the model test in vibration waveform, amplitude, and frequency characteristics. The peak values corresponding to the passing frequency of train carriage geometry (lc = 25 m), bogie (lab = 7.5 m), and axle distance (lwb = 2.5 m) respectively reflect the characteristic frequencies of the train compartment, adjacent bogie, and wheel load passing through. The peak velocity significantly depends on the distance from the track center in the horizontal direction, of which the attenuation follows the exponential curve distribution. The vibration velocities decrease rapidly within embankment, show a vibration enhancement region from raft to the 1 m depth of foundation soil, then decreases gradually along the subsoil foundation, to a very low level at the bottom of the subsoil, which is much lower than that at the track slab and roadbed. The pile-raft composite foundation can reduce the vibration level effectively and improve the safety of trains running in soft soil areas.

Study on the High-Speed Milling Performance of High-Volume Fraction SiCp/Al Composites.

Compared with other materials, high-volume fraction aluminum-based silicon carbide composites (hereinafter referred to as SiCp/Al) have many advantages, including high strength, small change in the expansion coefficient due to temperature, high wear resistance, high corrosion resistance, high fatigue resistance, low density, good dimensional stability, and thermal conductivity. SiCp/Al composites have been widely used in aerospace, ordnance, transportation service, precision instruments, and in many other fields. In this study, the ABAQUS/explicit large-scale finite element analysis platform was used to simulate the milling process of SiCp/Al composites. By changing the parameters of the tool angle, milling depth, and milling speed, the influence of these parameters on the cutting force, cutting temperature, cutting stress, and cutting chips was studied. Optimization of the parameters was based on the above change rules to obtain the best processing combination of parameters. Then, the causes of surface machining defects, such as deep pits, shallow pits, and bulges, were simulated and discussed. Finally, the best cutting parameters obtained through simulation analysis was the tool rake angle γ0 = 5°, tool clearance angle α0 = 5°, corner radius r = 0.4 mm, milling depth ap = 50 mm, and milling speed vc = 300 m/min. The optimal combination of milling parameters provides a theoretical basis for subsequent cutting.

Critical Speed Analysis of Rotor System of Sealing Machine

The sealing machine is the key part of the copper pen tip processing machine, and its working stability will have a direct impact on the processing quality of the pen tip. Taking copper pen tip desktop processing equipment for an example, to improve the quality of pen tip, the modal analysis was carried out on the system by large-scale finite element analysis software ANSYS. The modal parameters of the rotor system were calculated, and through the Campbell diagram, the critical speeds of the system were obtained. Finally, the critical speed under different structural parameters is obtained. By analyzing data, the critical speed of the system is negatively correlated with the bearing spacing, and positively correlated with the diameter of the long shaft section, and independent of the bearing stiffness. The analysis results provide a theoretical basis for the optimization design of structural parameters of the system and the design of the maximum working speed, which also has certain reference value for the research and design of copper pen tip desktop processing equipment in China.

Mechanical Behavior and Structure Optimization of Compressed PHP Packer Rubber

One of the core tools of horizontal well-staged fracturing completion technology is the compressed packer. The sealing and stability of packer rubber are key factors affecting the safe exploitation of high temperature, high pressure, and deep, complex oil and gas resources. The phenomenon of low setting pressure and early setting failure frequently occurs due to the unreasonable sealing structure. Therefore, in this paper, the tensile test of dumbbell hydrogenated nitrile butadiene rubber (HNBR) samples is conducted, and the stress-strain data of HNBR were obtained. The finite element mechanical model (FEM) of compressed PHP packer is established with consideration of material nonlinearity, geometric nonlinearity and double contact nonlinearity by adopting large-scale finite element analysis software ANSYS Workbench, verified by measured test data. Based on the verified FEM, the mechanical behavior and sealing performance of the original rubber under different setting loads are simulated. The contact pressure and its distribution, deformation, compression stroke of rubber and the relationship between them and axial loads are obtained. The mechanical behavior and sealing performance of packer rubber under different heights, thicknesses, external bevel angles, loading modes and steel-rubber friction coefficients with and without outburst prevention devices are investigated systematically using a manual-graphical optimization trial method. Results show that the packer rubber with the height of 75 mm, external bevel angle of 45°, steel-rubber friction coefficient ranging from 0.10 to 0.15 and outburst prevention devices can achieve the largest contact pressure and best sealing performance by adopting the setting method of bidirectional loading.

Influence of Subgrade Splicing Mode and Width on Differential Settlement of Pavement Subgrade

In order to study the influence of subgrade splicing mode and width on differential settlement, the large-scale finite element analysis software ANSYS is used to establish the subgrade settlement model, in which the parameters are determined according to the actual subgrade width, widening mode and engineering geological conditions of the widening project of Anxin expressway. The influence of unilateral widening and bilateral widening on the settlement of widened subgrade, the maximum differential settlement on the top of widened subgrade and the influence on horizontal displacement of widened subgrade are systematically evaluated. The results show that for unilateral and bilateral widening, with the increase of widening width, the settlement of the middle line of the old road gradually increases, and the double side widening can make the weight of the widened embankment distribute to both sides of the old subgrade, which greatly improves the settlement coordination of the old and new Subgrade, and is beneficial to the stress of the pavement structure.

Research on Construction Control Technology of Large-Span and Small Clear Distance Underpass High-Voltage Line Tunnel

Hanping tunnel is a control project of national highway 310 Dahejia to Qingshui highway project. It needs to cross a 330kV high-voltage transmission line under the condition of small clear distance, which requires high construction requirements. In view of the difficulties such as shallow buried depth of tunnel and small clear distance between tunnel and tower of high-voltage line, multiple excavation blasting method is adopted, and smooth blasting, charge quantity control and damping hole setting are comprehensively used to reduce the impact on the tower and structure of high-voltage line. In order to ensure the smooth progress of the project, the large-scale finite element analysis software is used to simulate the whole excavation project. The influence of the full-section method and the middle partition wall method (CD method) on the surrounding rock and the high-voltage electric tower is compared. It is found that the CD method can effectively control the displacement of the surrounding rock and the tower on it and the uneven settlement.

Development of a settlement prediction model for upper subgrade layers of ballasted tracks

Recently, settlement in railway tracks is posing a serious challenge. In particular, ballasted tracks can experience settlement due to repeated dynamic loading and various geotechnical factors such as consolidated settlements of natural foundation soil and poor compaction, which lead to track irregularities. Among these factors, settlement in track foundation has been identified as the primary cause of track irregularities. Such settlement mainly results from permanent deformation, a form of progressive settlement found in the upper subgrade due to the repeated dynamic loading of trains. As such, it is necessary to conduct a behavioral analysis of upper subgrade soil, which is susceptible to permanent deformation. A large-scale finite element analysis was performed using an existing permanent deformation prediction model to analyze the effects of permanent deformation on settlement in underlying soil materials of ballasted tracks. The results were used to propose a prediction model for settlement in the upper subgrade of ballasted tracks. The proposed model allows more accurate predictions of settlement that may occur in the upper subgrade of ballasted tracks, and can also be employed in predicting track irregularities.

How to efficiently apply soft thin coating to existing Finite Element contact model

In case of very thin surface coatings, the coating layer is often ignored in a large-scale Finite Element Analysis. This is mainly due to extensive numerical cost required to capture the correct mechanical behaviour of the layer, especially if the coating is significantly softer than the substrate.To overcome the excessive computational cost, due to the full discretization of the thin layer, in large-scale structural contact simulations one can consider a polynomial approximation of the solution field inside the layer. This formulation allows for a reduced representation of the surface layer and proves to be suitable for incorporation within existing finite element codes. Inclusion of the method scales down to an additional stiffness to the system of equations. Furthermore, it can be used in a classical finite element contact solver without strong additional modifications.Significant computational cost reduction is obtained for proposed 2D test-cases in comparison to fully discretized layer approach. It is especially apparent with soft layers on harder substrates. Hence, it is a promising method to be used in large scale structural simulations for studying the mechanical behaviour of systems with thin soft coatings.

Performance analysis and comparison study of two aluminum alloy joint systems under out-of-plane and in-plane loading. An experimental and numerical investigation

The static behavior of the traditional aluminum alloy Temcor (AAT) joint system and a new aluminum alloy hollow prism-plate (AHP) joint system is studied experimentally. The bending moment-rotation curves and failure modes for the two joint systems under out-of-plane bending (Mx) and in-plane bending (My) are obtained. The test results indicate that the bending stiffness and carrying capacity of the new hollow prism-plate (AHP) joint is superior to that of the traditional Temcor (AAT) joint. The refined finite element model (FEM) of the two kind of aluminum alloy joint systems are established based on a large-scale finite element analysis software. The simulation results are verified by comparing with the experimental results. Finally, to investigate the mechanical behavior and force transfer mechanism of the new hollow prism-plate (AHP) joint system, the parametric analysis is carried out to obtain the moment-rotation (force-displacement) curves and failure modes of the joint system under different loading conditions, including axial compression force, axial tension force, bending with compression force, and bending with tension force.

A condensed dynamic model of a heavy-duty truck for optimization of the powertrain mounting system considering the chassis frame flexibility

The existing powertrain mounting models of the heavy-duty truck for optimizing the mounts parameters cannot well describe the deformation of the chassis frame. To overcome this disadvantage, a new full vehicle model is proposed which embraces the view of system modeling and includes the frame flexibility. The model can achieve optimal parameters of the Powertrain Mounting System for isolating the vibration transmitted from the powertrain to the chassis. A model reduction technique, improved reduced system, is used to obtain a reduced model of the frame to represent its original large-scale finite element analysis model for the accessibility of time-efficient solutions of the model. The reduced frame model is integrated with the powertrain mounting and suspension model to form the full dynamic model of the vehicle. The accuracy and effectiveness of the proposed model are evaluated by its original vehicle model built in software ADAMS and an existing rigid model with rigid foundation. A hybrid model optimization strategy is also presented to tune the dynamic parameters of the powertrain mounts using the developed coupling model. The simulation results show that the proposed coupling model has better representation of the dynamic characteristics of the real vehicle system, and the presented hybrid model optimization strategy can obtain better optimization results compared with the existing rigid model with rigid foundation. In addition, the application of the proposed model can also be extended to the vibration control and the structural fatigue prediction.

SFEA: A Secure Finite Element Analysis Technique

Designers need a way to overcome information-related risks, including information leakage and misuse by their own collaborators during collaborative product realization. Existing cryptographic techniques aimed at overcoming these information-related risks are computationally expensive and impractical even for moderate problem sizes, and legal approaches such as nondisclosure agreements are not effective. The computational practicality problem is particularly pronounced for computational techniques, such as the finite element analysis (FEA). In this paper, we propose a technique that enables designers to perform simulations, such as FEA computations, without the need for revealing their information to anyone, including their design collaborators. We present a new approach, the secure finite element analysis approach, which enables designers to perform FEA without having to reveal structural/material information to their counterparts even though the computed answer depends on all the collaborators' confidential information. We build secure finite element analysis (sFEA) using computationally efficient protocols implementing a secure codesign (SCD) framework. One of our findings is that the direct implementation of using SCD framework (termed as naïve sFEA) suffers from lack of scalability. To overcome these limitations, we propose hybrid sFEA that implements performance improvement strategies. We document and discuss the experiments we conducted to determine the computational overhead imposed by both naïve and hybrid sFEA. The results indicate that the computational burden imposed by hybrid sFEA makes it challenging for large-scale FEA—our scheme significantly increases the problem sizes that can be handled when compared to implementations using previous algorithms and protocols, but large enough problem sizes will swamp our scheme as well (in some sense this is unavoidable because of the cubic nature of the FEA time complexity).

Development of Large-Scale Finite Element Solver for Wind Turbine Blade Structure Using Balancing Domain Decomposition Methods

In a wind turbine blade, laminated plates consisting of fiber reinforced plastic materials are generally used due to its high specific strength. We have been developing a large-scale finite element solver to analyze the wind turbine blade structure. For such a structure, the laminated finite element is frequently used in modeling. Each laminated finite element has multiple layers, each of which is an orthotropic body in order to model the layered fiber reinforced materials with different fiber directions. Also, since a realistic wind turbine blade structure generally requires a large number of finite elements for discretization, we adopted a domain decomposition method, which is one of the numerical methods to parallelize the finite element method for large-scale analyses. Domain decomposition methods have been studied mainly in the mathematics field and applied to large-scale finite element analyses of realistic structures. However, the application studies do not sufficiently cover practical engineering models such as the model with laminated finite elements with orthotropic layers. Some researchers in the field of domain decomposition methods stated that the change or the jump of material parameters may degrade convergence performance of the iterative solver. Therefore, we investigated the convergence performance in the present study. The convergence performance of the balancing domain decomposition preconditioner and its variations implemented in our solver were compared. The numerical tests show that thin laminated finite elements with high aspect ratios significantly increase the number of iteration counts. Moreover, the consideration of material parameter changes in the balancing domain decomposition preconditioner (the Scaled-BDD method) attained a smaller number of iteration counts than the straightforward implementation.