Damage and fracture are the main causes of structural failure, which have a significant impact on engineering safety. Crack propagation problem is also a fundamental scientific challenge that needs to be solved urgently. In this paper, the relevant theoretical basis for simulating damage and fracture, such as a fracture mechanics model, damage evolution model and numerical calculation methods, such as the finite element method, boundary element method and peridynamics theory, are introduced in the form of literature review. This paper also reviews the commonly used CAE software for structural damage and fracture analysis, including general-purpose finite element programs such as the damage and fracture analysis module that comes with ABAQUS, as well as specialized fracture analysis software, damage tolerance tools, fatigue life analysis tools, etc. The development status of some autonomous CAE software is also discussed. Finally, this paper analyzes some challenges faced by CAE software for damage and fracture simulation, and looks forward to the future development direction of domestic CAE software.

The power battery pack of an electric vehicle is a complex system, whose efficient and high fidelity modeling is an urgent need for solving collision problems. This paper firstly proposes a hybrid reduced order battery pack model, with fine modeling in the central region and centralized mass in other parts through a simple connection contact. Compared with the refined full model, the maximum stress error is relatively small, and the computational efficiency is improved by about 3.5 times. Then, to consider the effect of the boundary further, a centroid module structural model with equivalent contact is proposed. Compared with the hybrid reduced order model, the collision displacement and the maximum stress of the centroid module structure model are much closer to those of the fine full model. Finally, an impact response analysis is conducted on the centroid module structural model and the fine full model, by comparing the behaviors of the collision center point and the impact object. It is found that both models have the similar trend in the response curves with small errors, which verifies the feasibility of the proposed model.

Considering the issue that low frequency and broadband of elastic wave metamaterials cannot coexist, this paper realizes a low-frequency band gap by rotating asymmetric mechanical metamaterials, and further widens the low-frequency bandgap by introducing multiple orders. By utilizing the node rotation and ligament bending deformation characteristics of anti-chiral materials, the vibration body size and ligament stiffness of the anti-tetra chiral unit cell diagonal are gradually adjusted through ligament folding, and the multi-order asymmetric unit cell design is realized. The generation and change mechanism of elastic wave bandgap are explained by analyzing the resonance mode and transmission characteristics of the upper and lower bounds of the bandgap. The study shows that: in the asymmetric mode, the node rotation and ligament bending deformation characteristics of chiral materials are utilized to realize the rotation resonance of the mass block and open the bandgap, and the band gap is widened by the resonant superposition between two pairs of different mass blocks arranged alternately. Finally, the proposed asymmetric mechanical metamaterial is verified by experiments to have to demonstrate improved broadband and low-frequency vibration isolation performance.

A surrogate model is a new research idea direction of aerodynamic data generation. A traditional surrogate model relies on a large number of high-precision simulation sample points and their responses values to ensure the accuracy of the model. A multi-credibility surrogate model can reduce the computational cost while maintaining a certain accuracy by integrating multi-layer high and low credibility models, which is of great significance for reducing a missile development cycle. In this paper, the influence of different numbers of low-confidence sample points on the multi-confidence model and the optimal ratio of high-low-confidence sample points are studied, and a multi-confidence sampling method suitable for aerodynamics data is proposed. It is applied to the construction of three multi-credibility surrogate models in the prediction of missile aerodynamic data, among which the Co-Kriging model has the best comprehensive prediction effect. The recommended ratio of high and low confidence sample size is between 1: 4 and 1: 3.

This paper presents a Bezier triangle meshing method that considers both clipped and non-clipped forms for a single NURBS surface. The proposed method is applied to analyze isogeometric Kirchhoff-Love shell structures. The process begins by interpolating NURBS surfaces into Bezier surfaces. Subsequently, the topological relationship between the clipping curve and each parameter node is calculated within the parameter domain. A Bezier contour curve set is then generated in the parameter domain by selecting points along the clipping curve. Utilizing this contour curve set, a triangular mesh is generated in the parameter domain. Finally, the Bezier triangle mesh in the physical domain is created through a mapping method. The adaptability and robustness of the algorithm are verified through three models, and the mesh quality is assessed. The results demonstrate favorable overall mesh quality. Building upon this foundation, the paper illustrates the application of a rotation constraint between Kirchhoff-Love shell elements, using the penalty function method with Scordelis-Lo's Roof shell model as an example. The accuracy of Kirchhoff-Love shell elements based on Bezier triangles is subsequently validated.

The formation of porous media is influenced by a number of factors, including the deposition and fragmentation of particles, which result in the formation of interlayers with varying structures. These interlayers exert a significant influence on the mechanical behavior of porous media. This paper presents a systematic investigation into the influence of the inclination angle and thickness of the interlayer on the mechanical behavior of porous media, employing the discrete element method. The results demonstrate that the stress intensity of porous media containing interlayers is between those of the two homogeneous porous media and varies with changes in the inclination angle and thickness of the interlayers. The average coordination number between grains is found to be significantly affected by the thickness of the interlayer at the beginning of loading, but stabilized at the end of loading. The variation of the coordination number affects the distribution of strong and weak force chains, while the inclination angle and thickness of the interlayer determine the magnitude and direction of stress transfer in the force chains. Furthermore, the contact unit normal force and normal contact force are deflected with the increase of the inclination angle of the interlayer, demonstrating significant anisotropy. This study advances our understanding of the intricate mechanical behavior of porous media containing interlayers in strata, offering invaluable insights for optimization and practical application in geological engineering.

The discontinuous Galerkin (DG) method has been widely adopted due to its excellent properties such as high accuracy and ease of parallelization. The adaptive mesh refinement (AMR) technique has been widely adopted to improve computational efficiency with much less computational cost compared with uniform global refinement to the same level with AMR. This paper combines the advantages of DG and AMR, and a new hybrid limiter is applied to the DG method on adaptive Cartesian grid based on p4est, an open-source library. The limiter exhibits advantages of high precision, compactness, robustness, and ease of implementation. The shock wave is captured with a shock indictor and the performance of the new hybrid limiter is compared with that of the total variational bounded (TVB) limiter in this paper. The result shows that the performance of the former is significantly better than that of the latter. A series of numerical examples for Euler equations and Navier-Stokes equations are used to verify the feasibility and efficiency of the proposed method. The results show that the new hybrid limiter performs very well in the AMRDG method, it has lower dissipation and great shock capture ability, and the computational efficiency is greatly improved while the accuracy is guaranteed.

Small cross-sections of boundary elements easily induce the “internal tension” phenomenon of steel plate shear walls, making it difficult to fully utilize the seismic performance of buckling-restrained steel plate shear walls. The design of cross-sections of boundary elements is related to their internal force requirements, and analyzing the internal force requirements of boundary columns is meaningful. Based on the proposed buckling-restrained steel plate shear wall with multi-concrete panels (MBRSPSW), the analytical expressions for the internal force of the boundary column of the MBRSPSW were theoretically derived in this paper. Combined with the experimental research on the buckling-restrained steel plate shear wall horizontally assembled multi-concrete panels (H-MBRSPSW), its numerical model was established and verified. The internal force distributions of the boundary column obtained from numerical analysis and analytical calculation were further compared. The research results indicate that the inner steel plates in the MBRSPSW are divided into constrained regions and unconstrained regions. The axial force, shear force, and bending moment distributions of the boundary column from the analytical calculation results agree with those from the numerical analysis results, and the internal force calculation expressions of the boundary column are correct. The research results can provide a reference for the design of this category of steel plate shear walls.

The non-isothermal complex flow caused by fluid impacting obstacles is very important to the industrial processes such as nuclear energy utilization. Through coupling various numerical techniques such as the density diffusive term, artificial viscous term, particle shifting technique, a stable and accurate non-isothermal smoothed particle hydrodynamics (SPH) scheme is established, and accurate simulation of non-isothermal complex flow caused by fluid impacting obstacles is realized. Based on the simulation for the non-isothermal flow past a heated cylinder, the non-isothermal dam break past single/multiple obstacles, it is demonstrated that: (1) the developed non-isothermal SPH scheme can not only compute a smooth pressure field and avoid the spurious oscillation of numerical solutions, but also predict accurately the temperature field and the key physical quantities; (2) this SPH scheme can also accurately show the interaction between the heat conduction process and the complex free-surface evolution, and has the capability to simulate non-isothermal complex flows past multiple obstacles.

A simple numerical implementation method is proposed for the Chaboche-type viscoplastic constitutive model coupled with Lemaitre anisotropic damage theory. Using the decoupled algorithm, the damage tensor is updated based on the forward difference format at the beginning of each incremental step. The damage tensor is considered as a constant in the discretization process of the constitutive equations. Based on the hypothesis of strain equivalence, the formulations containing only partial tensors are constructed in the effective deviatoric stress space, and the radial return process is simplified to solve a nonlinear scalar equation concerning the accumulated plastic strain increment. The numerical implementation method and the derivation of consistent tangent operator are provided based on the Voigt notation scheme. The comparison between the experimental data and the simulation results of isotropic scalar damage model under uniaxial and multiaxial stress states validates the effectiveness and high computational efficiency of this method. Numerical results under different time step sizes also indicate the good accuracy and stability.