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.

Proppant transport in fractures is essentially a dense granular flow in a slot-shaped space. Applying the two-fluid method in numerical simulations of a field-scale particle flow is promising, but existing solid stress models cannot accurately describe the process of proppant accumulation. In this paper, the morphological change of a proppant pack under flow erosion was analyzed experimentally, and the important influence of cohesion on the change of the pack state was pointed out. Then, combined with the simulated results of a proppant transport and the results of a suspension apparent viscosity test, the influence of the particle radial distribution function on the solid kinetic pressure and the change trend of total solid pressure were analyzed, and the change rate of the solid friction pressure with the particle volume fraction was determined. Based on the granular matter theory and results of a direct shear test, the cohesion of the proppant pack was considered in the frictional viscosity model. The results show that the improved solid friction stress model can capture larger angles of the accumulation and settlement profiles, and correctly simulate the process of proppant accumulation.

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.

To investigate the evolution of dimpling and the mechanism of interface separation in bimetal clad pipes under external mechanical loading, a stress model was established. The study analyzed the effects of the ratio of diameter to thickness for the inner and outer pipes, forming pressure, initial forming clearance, and operational internal pressure on dent formation and interface separation. Results indicate that interface separation distance and rebound rate correlate positively with the ratio of diameter to thickness for the inner pipes, forming pressure, and initial forming clearance, and negatively with the ratio of diameter to thickness for the outer pipes. Higher operational internal pressure reduces interface separation but increases rebound rate. Internal pressurization of dented pipes decreases interface separation; for instance, under 2-MPa operating pressure, interface separation is 5% less compared with conditions under 2-MPa pressurization. Additionally, the difference in separation between these conditions decreases with increasing pressure. Adjacent dimpling results in increased interface separation in intermediate pipe segments, causing a broader interface separation area compared with isolated dimpling.

Accurately simulating the impact characteristics of a dam break is of paramount significance for the prediction and mitigation of dam-break flow disasters. The B-spline material point method (BSMPM), as an improved algorithm of the material point method (MPM), effectively enhances computational accuracy and improves convergence. However, the BSMPM solves the governing equations based on a tensor grid rather than an Eulerian background grid. Moreover, its interpolation shape functions have a larger influence domain. Consequently, when solving problems involving fluid-structure coupling and contact, issues such as premature contact, difficulty in capturing contact interfaces, and challenges in calculating contact forces arise. Within the same tensor grid space of the BSMPM, accurate capture of contact interfaces is achieved based on the relative velocities and unit outward normals of the same nodes; employing the Greville Abscissa enables precise contact of contacting objects, thereby avoiding premature or spurious contact; through the Lagrange multiplier method, interface contact forces are accurately determined, thus constructing a high-precision contact algorithm for fluid-structure strongly coupled problems, facilitating research on the simulation of dam-break fluid impact with rigid and elastic obstacles, and enabling a comparison with existing experimental or simulated results. The results demonstrate that the simulated impact loads and structural deformation evolution patterns correspond well with existing experimental/simulated results. For rigid obstacles, the peak impact pressure exhibits concave parabolic growth and positive correlation exponential function growth with increasing water level and dam-break slope, respectively. For elastic obstacles, the peak impact pressure decreases exponentially with the increase in the height of the probing point. The feasibility and effectiveness of simulating dam-break flow impact problems using the BSMPM contact algorithm are validated, providing a new perspective for simulating dam-break flow impact problems.

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.