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In this paper, the meshless method is extended to simulate the interaction between soil and structure through 2D finite element (FE) model. The background mesh line shared by each surface of interface is introduced for Gauss points' generation and interpolation. Thus, instead of a series of interface elements, the whole soil–structure interface can be presented by an arbitrary number of nodes with flexible distribution on the contacting surfaces. The radial basis function (RBF) is introduced as the interpolation function to obtain the displacement of each Gauss points by surrounding the nodes along the surfaces. The research of shape parameters and the rate of convergence are also conducted. With non-matching nodes interface, the soil and structure zone can be modeled independently and connected with the proposed non-matching nodes interface flexibly and effectively. Furthermore, the proposed method can easily enable cross-scale modeling, which has high utility for enabling refined analysis without excessively increasing the computational costs. In addition, under the standard finite element framework, nonlinear constitutive models can be employed to capture the complex behaviors at the interface. Several simulations are presented to demonstrate the high flexibility, extensive applicability and precision of the proposed non-matching nodes interface based on meshless method. [ABSTRACT FROM AUTHOR]

The tetrahedrons offer advantages in terms of its adaptability to complex geometries and high-efficiency of automated discretization. However, the performance is greatly limited by the weak accuracy suffered from first-order elements, as well as the significant computational burden required for quadratic cells. In this paper, a flexible mixed-order tetrahedron element is constructed on the basis of SBFEM theory, specifically, a formula for the interpolation of circumferential boundary is developed with the union of quadratic and first-order seamlessly, benefiting the combination of triangle area coordinates and the line drawing approach. Additionally, a flexural angle index of tetrahedral edges and regional customization are proposed as the modification method for determining order conversion. Subsequently, the accuracy of the proposed method in addressing various issues is investigated. The results show that the performance of tetrahedrons is satisfactorily enhanced through the utilization of 64 distinct order combination modes; and compared with its quadratic form, the calculation workload has been effectively decreased with no loss of accuracy. In summary, the analytical performance of tetrahedrons can be enhanced reasonably, which provides an effective approach for rapid and accurate analysis for critical structures. [ABSTRACT FROM AUTHOR]

This study constructed the u-p equation for saturated soil in the meshfree global weak form within the arbitrary Lagrangian-Eulerian (ALE) framework to solve the problem of liquefaction-induced large deformation induced by strong seismic loading. The interpolation improvement in the near-interface zone was achieved using domain truncation optimization and the local nodal refinement algorithm, and the relative error of the shape function was proposed as the judgment criterion for radial basis function (RBF) field variable mapping. Finally, a high precision meshfree liquefaction-induced large deformation method (MFLLDM) with automatic time step mapping and interfacial zone interpolation improvement was established. The MFLLDM achieved the efficient dynamic updating of soil stress state and pore pressure information in space during the deformation process and more accurately depicted the localized large shear deformation characteristics of the soil in the near-interface zone. The proposed method was integrated into a custom-built large-scale finite element method (FEM) computing system (GEODYNA), based on object-oriented and super element program design technology. This enabled the efficient coupled analysis of MFLLDM in the liquefied-induced large deformation zone and FEM in the small deformation zone. Numerical consolidation examples were used to validate the accuracy, convergence, and applicability of the soil elasto-plastic model for MFLLDM. The method was then used to simulate the liquefaction damage of the San Fernando dam, which reproduced the development process of large slip deformation and high-water pressure ratio for the upstream dam slope. [ABSTRACT FROM AUTHOR]

• Mixed interpolation interface is introduced to solve discontinuous SSI problems. • The introduced method is integrated into FEM frameworks. • A crack evolution analysis is carried out for high concrete pedestal. • Cracking develops from the upstream of pedestal and extends to inner zone. Structural discontinuities are common (e.g. cracks, segmented structures) especially in large-scale geotechnical structures, which can lead to the discontinuous soil-structure interaction (SSI) problems. Thus, in this paper a mixed interpolation interface with non-matching nodes is introduced for effectively simulating discontinuous SSI problems. This paper provides a conveniently executed numerical implementation of the introduced approach within a finite element method (FEM) analysis platform. The high flexibility and precision of the developed method are demonstrated through fine analyses of 2D and 3D concrete faced rockfill dams (CFRDs). Furthermore, a cracking evolution analysis for a high pedestal of the Quxue asphalt concrete core dam is conducted by coupling the method with a cohesive zone model (CZM). The mixed interpolation interface is verified as an effective tool for solving discontinuous SSI problems. The modeling also sheds light on the process of cracking evolution and the primary failure mechanism for high pedestal. [ABSTRACT FROM AUTHOR]