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A novel artificial boundary method called the scaled boundary perfectly matched layer (SBPML) is proposed for the transient analysis of elastic wave propagation in unbounded domains. This method constructs a generalized perfectly matched layer (PML) around the finite interior subdomain based on a coordinate transformation inspired by the scaled boundary finite element method (SBFEM). It can model the infinite exterior subdomains of heterogeneous materials, featuring both parallel and radial straight‐line physical surfaces and interfaces. In addition, generally‐shaped (even nonconvex‐shape) artificial boundaries can be used to provide high flexibility in choosing the geometry of the finite interior subdomain. Two coordinate mapping technologies, namely the modified scaled boundary coordinate transformation from the SBFEM and the complex coordinate stretching from the PML, are successively utilized to construct the proposed method. By introducing the integral of stress as an auxiliary variable, the resulting SBPML subdomain is represented in the time domain using a mixed displacement‐stress unsplit‐field formulation. This has the added benefit of allowing for easy incorporation into standard dynamic finite element methods. The performance of the SBPML is demonstrated through several numerical examples, including P‐SV and SH wave propagation problems occurring in unbounded domains with complex geometries and heterogeneous material properties. The numerical results are evaluated in comparison to both reference solution and existing artificial boundary methods, ultimately demonstrating the flexibility, robustness, accuracy, and stability of the proposed approach. [ABSTRACT FROM AUTHOR]

Interaction between underwater shock waves and structures has attracted significant interest of many researchers. This study aims to develop a method to solve two-dimensional (2 D) fluid-structure interaction problems during far-field underwater explosion (UNDEX). The acoustic domain which can undergo small pressure variations is considered to describe the fluid-structure interaction during UNDEX. First, the empirical formula of the incident shock waves is considered as free wave motion of the fluid, and the fluid domain is Discretized by the finite element method. Based on the scaled boundary finite element method (SBFEM) and continued fraction solution, an artificial boundary condition (ABC) with high accuracy in time domain is adopted to simulate the truncated infinite domain, which can be placed very close to the radiating field is adopted to simulate the truncated infinite domain. Third, an internal substructure method (ISM) to calculate the equivalent input shock wave loads is proposed. Finally, the proposed method is used to study the scattered waves on a rigid circular structure due to the shock wave, and the effect of the radiation wave due to the motion of the structure on the dynamic responses of the circular structure during UNDEX is studied. [ABSTRACT FROM AUTHOR]

In this paper, a novel crack and void identification method is proposed based on the scaled boundary finite element method (SBFEM) with the pixel-based quadtree mesh and the parameter level set method (PLSM), in which the particle swarm optimization method (PSO) is applied to optimize the objective function. It fully exploits the advantages of fast image-based quadtree mesh generation and efficient assembly of global stiffness matrix to accomplish a fast analysis of the forward problem and accelerate the efficiency of the inversion. Furthermore, multiple level set functions are introduced to represent cracks and voids simultaneously. The application of PSO dexterously avoids the difficulty of solving sensitivity. Numerical examples show that the proposed method can identify the position and shape of cracks and voids accurately by discussing different influencing factors. In addition, the method has shown certain anti-noise performance. [ABSTRACT FROM AUTHOR]

Point-cloud-based geometry acquisition techniques have seen an increased deployment in recent years and can be used in many branches of science and engineering. Different from conventional computer aided design (CAD) models, point-cloud data can be directly obtained by applying surveying technology, such as laser scanning devices. This opens a pathway to an efficient and highly automatic acquisition of the geometric model. However, in order to perform numerical analysis on point-cloud models using conventional finite element approaches, a surface reconstruction is required, which is both time consuming and error-prone. Therefore, a direct numerical analysis framework based on point-cloud data in conjunction with polyhedral element techniques is developed in this contribution. To this end, a robust and efficient meshing paradigm based on the direct use of point-cloud data (without surface reconstruction) is proposed. From the geometric model, a trimmed octree mesh containing only a limited number of master elements (element patterns) is directly generated, which is highly suitable for pre-computation techniques and parallelization (high-performance computing–HPC). By computing the element stiffness and mass matrices from pre-computed master elements via scaling, a fully automatic HPC framework is developed. By means of six numerical examples, we demonstrate the robustness, versatility, and efficiency of the developed methodology in handling (geometrically) complex engineering problems. • Point cloud-based direct structural analysis of geometrically complex domains. • Automatic mesh generation (i.e., no user intervention) from point cloud models. • Highly efficient pre-computation technique based on octree discretizations. • Parallel explicit dynamic analysis exploiting octree element patterns. [ABSTRACT FROM AUTHOR]

An automatic approach for 3D analysis of acoustic-structure interaction problems is proposed based on the scaled boundary finite element method (SBFEM). The acoustic domain studied in this paper is assumed to be infinite. The infinite acoustic domain is divided into a near field (bounded domain) and a far field (unbounded domain). The acoustic near field contains structures of arbitrary shape, while the far field represents the unbounded acoustic domain. For modeling the wave propagation accurately and efficiently, continued fractions are employed to evaluate the dynamic stiffness and impedance of subdomains in both structural and acoustic domains. The time-domain equations for both structural and acoustic domains can be obtained by introducing auxiliary variables. Via satisfying the boundary conditions on the acoustic-structure interface, the global system of equations for acoustic-structure interaction system can be constructed. Symmetric formulations can also be obtained for this coupled system. Since the SBFEM requires the discretization of only the boundary, the mesh transition on the acoustic-structure interface is easily addressed by the subdivisions of 2D surface elements. Automatic meshing techniques can be incorporated in the proposed approach to generate meshes directly from the input geometrical models. Numerical examples are presented to demonstrate the accuracy, efficiency and potential of the proposed approach for modeling complex 3D acoustic-structure interaction problems. [ABSTRACT FROM AUTHOR]

Abstract The coupling of non-matching meshes is of great interest in the field of computational mechanics. It reduces meshing burden by allowing users to divide a problem domain into several simpler subdomains and generate meshes for them independently. In this paper, a coupling method using arbitrary polyhedron elements is presented. On the interface of two non-matching meshes, a new surface mesh of polygon elements is constructed by merging the non-matching meshes. A shifting procedure is designed to prevent the distortion of surface elements. The polyhedron elements connected to the interface are modified by replacing their faces on the interface with the new polygon elements, leading to matching discretization on the interface. The modified polyhedron elements are modeled by the scaled boundary finite element method and no further volume discretization is required. No interface constraints or special shape functions are required in the analysis. Seven numerical examples are presented to demonstrate the versatility and robustness of the proposed procedure. Convergence behavior is also examined. Highlights • Non-matching meshes at their interfaces are converted to matching meshes using a polytree algorithm. • Polyhedron elements requiring on surface discretization are employed. • Displacements are conformable at the interfaces. • No interface constraints are required. • Applications facilitating the mesh generation of complex geometries are demonstrated. [ABSTRACT FROM AUTHOR]

Highlights • SBFEM is applied to model 3D bounded and unbounded acoustic problems. • The high-order doubly-asymptotic open boundary is extended to model 3D unbounded acoustic domains. • The global system of equations for bounded and unbounded acoustic domains is directly applicable to time-domain analysis. • The octree mesh technique is implemented to reduce human efforts with respect to mesh generation from models with complex geometries. • The proposed approach is suitable for automatic analysis of scalar wave propagation in 3D infinite medium. Graphical abstract Abstract An automatic approach for modeling acoustic responses of 3D bounded and unbounded domains is proposed based on the scaled boundary finite element method (SBFEM). The bounded acoustic near field is modeled by SBFEM. Due to the fact that SBFEM only requires boundary discretizations, the meshing process in this approach is automatically accomplished by introducing an octree-based meshing technique and boundary trimming. Therefore, models with very complex geometries can be analyzed automatically, i.e. no human input/intervention is needed/required. For modeling the unbounded acoustic far field, a spherical high-order doubly-asymptotic open boundary is developed for modeling scalar wave propagation in 3D unbounded domain. This doubly-asymptotic open boundary is able to represent the unbounded domain accurately and efficiently as it includes recursive continued-fraction expansions in both high and low frequency limits. The continued-fraction solutions are expressed in the time-domain by introducing auxiliary variables. The bounded and unbounded domains are coupled via the nodal fluxes on the near/far field interface. The final coupled ordinary differential equations can be solve using standard time-stepping methods directly for obtaining transient acoustic responses. Various numerical examples are presented in this paper for demonstrating the accuracy, efficiency and capability of this approach for analyzing acoustic problems with complex geometries. [ABSTRACT FROM AUTHOR]

Explicit time integration methods are an integral part of solving structural dynamics problems such as the propagation of elastic and acoustic waves, impact scenarios including crash tests and many more. One common limitation of this class of time integrators is, however, their conditional stability, meaning that highly distorted, small, or stiff finite elements typically govern the critical time step size. That is to say, even a small number of such elements will result in a significantly decrease of the feasible time step, which in turn drastically increases the computational costs of solving the semi-discrete equations of motion. This is especially true for non-uniform and unstructured meshes. Therefore, an asynchronous explicit solver in parallel is proposed in this article. The idea is to assign different time step sizes to different parts of the mesh, such that the overall computational effort is minimized. To improve the performance of the proposed solver, it is combined with a sophisticated octree meshing framework, where the balanced octrees are used, meaning that the ratio of the element sizes of adjacent elements cannot exceed a value of two. Thus, the critical time step of each element can be estimated straightforwardly. To avoid issues with hanging nodes, a special polyhedral element formulation, the scaled boundary finite element method, is employed. Since there are only a limited number of cell patterns in a balanced octree, the stiffness and mass matrices are pre-computed, significantly reducing the computational cost. Moreover, exploiting an element-by-element technique, the assembly of global stiffness matrices can be avoided. The main advantage of the described methodology is that the asynchronous explicit solver can be easily implemented in a high-performance computing environment. By means of several numerical examples, the accuracy and efficiency of the proposed method are demonstrated, as well as its versatility in handling complex engineering problems. • An asynchronous parallel explicit solver is developed for elasto-dynamic problems. • Different time step sizes determined by local element size. • Good scalability and parallel efficiency comparing with conventional parallel solver. • Seamless coupling with unique patterns of octree elements to increase efficiency. [ABSTRACT FROM AUTHOR]

As versatile materials with elevated mechanical properties, short fibre reinforced composites (SFRCs) are currently used in many applications. To enhance the mechanical properties, e.g. the ductility, or to reduce crack propagation, short fibres are added to a matrix material, such as polymers or concrete. In the case of concrete, for example, the composite might contain additional aggregates as well. Although the addition of fibres improves the mechanical properties in general, it is well‐known that many matrix materials exhibit creep deformations under constant long‐term loads. The contribution at hand discusses a scaled boundary approach to model the inelastic behaviour of SFRCs. To allow for an efficient and automated mesh generation, the scaled boundary finite element method (SBFEM) is used in conjunction with the quadtree/octree decomposition algorithm. Within this framework, the fibres are modelled in a discrete manner, and the mesh of the matrix is generated independently of the fibres. Applying a novel embedding method, the meshes of the matrix and the fibres are combined, which results in a compatible mesh without requiring additional constraints. Furthermore, it is straightforward to combine the discussed techniques with image‐based mesh generation, e.g. based on computed tomography scans. The current contribution presents various 2D and 3D examples illustrating the efficiency and adaptability of the proposed framework. In addition, we present a methodology to incorporate non‐linear constitutive models into the SBFEM. Separate constitutive equations are formulated for the matrix, aggregates, and fibres. Whereas the mechanical behaviour of the aggregates and the fibres can be modelled within the framework of elasticity, one must make use of non‐linear approaches to account for the rate‐dependent inelastic deformation of the matrix under multiaxial stress and deformation states. Overall, this method allows for the simulation of creep in SFRCs, while considering the complex microstructure of these materials in detail. This provides the basis for a realistic estimation of the effect of long‐term loading on SFRC components. [ABSTRACT FROM AUTHOR]

A direct time-domain approach to simulate seismic wave propagation in three-dimensional unbounded media is proposed based on the Scaled Boundary Finite Element Method (SBFEM). A domain of interest is commonly partitioned into a far field and a near field. The far field is modelled by the semi-analytical SBFEM satisfying rigorously the radiation conditions at infinity. Separate scaled boundary finite elements are employed to reach a balance between computational efficiency and accuracy. The near field is discretized into arbitrarily-shaped scaled boundary finite elements without the occurrence of hanging nodes. This advantage of the SBFEM in mesh generation is leveraged by incorporating the automatic octree-based meshing technique. By exploiting the geometrical similarity of both bounded and unbounded SBFE subdomains the computational cost is reduced. Inspired by the Domain Reduction Method (DRM), seismic waves are introduced to the system via a single layer of elements in the near field. This formulation of seismic input is mathematically convenient as it avoids the direct participation of the formulation of the far field. The proposed approach is attractive in a reliable simulation of the far field, flexible mesh generation of the near field and simple formulation of the seismic excitations. These merits are demonstrated through numerical simulations of seismic wave propagation in a free field and different examples featuring complex geometries in the near fields. • A direct time-domain approach to simulate seismic wave propagation in three-dimensional media is proposed. • Seismic wave fields in unbounded domains can be rigorously represented by SBFEM. • A bounded domain is be automatically discretized into polyhedra without hanging node problems. • Geometrical similarities of both bounded and unbounded domains are exploited to reduce computational costs. • A simple model for seismic wave inputs is presented base on the domain reduction method. [ABSTRACT FROM AUTHOR]

Typical areas of application of explicit dynamics are impact, crash test, and most importantly, wave propagation simulations. Due to the numerically highly demanding nature of these problems, efficient automatic mesh generators and transient solvers are required. To this end, a parallel explicit solver exploiting the advantages of balanced octree meshes is introduced. To avoid the hanging nodes problem encountered in standard finite element analysis (FEA), the scaled boundary finite element method (SBFEM) is deployed as a spatial discretization scheme. Consequently, arbitrarily shaped star-convex polyhedral elements are straightforwardly generated. Considering the scaling and transformation of octree cells, the stiffness and mass matrices of a limited number of unique cell patterns are pre-computed. A recently proposed mass lumping technique is extended to 3D yielding a well-conditioned diagonal mass matrix. This enables us to leverage the advantages of explicit time integrator, i.e., it is possible to efficiently compute the nodal displacements without the need for solving a system of linear equations. We implement the proposed scheme together with a central difference method (CDM) in a distributed computing environment. The performance of our parallel explicit solver is evaluated by means of several numerical benchmark examples, including complex geometries and various practical applications. A significant speedup is observed for these examples with up to one billion of degrees of freedom and running on up to 16,384 computing cores. • A parallel explicit solver is developed for elasto-dynamic problems. • Fully automatic octree mesh generation of complex geometry. • Developing lumped masses of octree elements in the SBFEM to avoid hanging nodes. • Identifying and using unique patterns of octree elements to increase efficiency. • Good scalability and parallel efficiency up to 16K cores and 1 billion DOFs. [ABSTRACT FROM AUTHOR]

In this paper, an adaptive refinement technique using the scaled boundary finite element method (SBFEM) is proposed. The salient feature of this technique is that it is not required to regenerate the mesh for the whole model during the iterations. To this end, a local mesh refinement strategy is implemented based on a polytree algorithm in three dimensions, which can be applied to polyhedral elements with arbitrary number of nodes, edges and faces. These elements constructed by the SBFEM can be used in analysis with their boundaries discretized only, which reduce the difficulty to connect elements with different sizes. An explicit residual based error indicator is developed using the discontinuity of the stress field to guide the adaptive mesh refinement. The accuracy and efficiency of the proposed method are demonstrated using five numerical examples, including complex geometry and stress singularity. • An adaptive analysis technique based on SBFEM is proposed. • Regenerating mesh for the whole model is not required. • Mesh is refined locally using a polytree based algorithm. • Polyhedral elements requiring on surface discretization are employed. [ABSTRACT FROM AUTHOR]

• SBFEM implementation of a non-linear material model for rate-dependent inelasticity • automatic meshing of complex (micro-)structures based on a quadtree-decomposition algorithm • detailed study on the influence of quadtree meshing and jagged boundaries in image-based analyses • efficient simulation of composites with randomly distributed aggregates of arbitrary shape • straightforward combination of elastic and inelastic material models for different constituents The contribution at hand presents the implementation of a non-linear constitutive model for rate-dependent inelasticity into the scaled boundary finite element method (SBFEM). To increase the numerical efficiency and simplify the formulation, the stress update algorithm is only performed at the scaling centre of the polytope elements. The presented SBFEM framework is ideally suited for the image-based analysis of composites since many matrix materials exhibit rate-dependent inelasticity, particularly at high temperatures. Thereby, meshes are generated based on images of the complex microstructures by employing an efficient quadtree-decomposition. The main advantage of this approach lies in its high degree of automation requiring only minimal intervention by the user. Various benchmark examples are presented to verify the formulation. Furthermore, the influence of jagged boundaries, resulting from the quadtree decomposition, on the accuracy and convergence of results is discussed in detail. The paper concludes with the study of a metal-matrix composite, whereby rate-dependent inelasticity is taken into account to model the mechanical behaviour of the matrix. [ABSTRACT FROM AUTHOR]

This paper introduces an automatic way of performing 3D static and dynamic elastoplastic analyses in the framework of the scaled boundary finite element method (SBFEM), which only requires the boundary discretization and thus can provide high flexibility in automatic mesh generation. The input models in this paper are described by Standard Tessellation Language (STL) format due to its simplicity and popularity in computer-aided design. The automatic mesh generation from any input geometry is achieved by utilizing the octree decomposition algorithm and boundary trimming. An efficient approach for 2D static image-based elastoplastic analysis based on SBFEM is extended to 3D static and dynamic elastoplastic analyses in this present work. In this improved approach, the return mapping algorithm is only required to be performed at the scaling center of each subdomain in the yield zone. Constant elastoplastic constitutive matrix and internal stresses are used within each yielded subdomain as well. This will greatly simplify the implementation of elastoplastic formulation and reduce the costs involved in the elastoplastic analysis as the return mapping algorithm is computationally expensive. Meanwhile, stabilization matrix is also introduced in the elastoplastic stiffness matrix to eliminate the spurious modes. Numerical examples are presented in this paper to show the feasibility and accuracy of the proposed approach as well as its capability of modelling complex structures in practical applications. [ABSTRACT FROM AUTHOR]

In this paper, an enhanced prismatic-element scaled boundary perfectly matched layer (SBPML) is developed, which is a novel time-domain artificial boundary method for 3D infinite wave problems. The SBPML permits the utilization of an artificial boundary with general geometry and can consider planar physical surfaces and interfaces extending to infinity. Moreover, this enhancement enables the seamless integration with surface meshes of arbitrary polygonal faces (such as triangles, quadrangles, pentagons, heptagons, octagons, etc.) at the truncation boundaries. The interior domain can be modelled by polyhedrons formulated by the scaled boundary finite element method (SBFEM). The geometric shape of the SBPML elements in the proposed method, within the local coordinate system, takes the form of a regular prism with regular polygonal top and bottom faces. Consequently, it is referred to as the Prismatic-element SBPML. Local scaled boundary coordinates based on the polygonal shape function are firstly introduced into the truncated infinite domain to describe its general geometry properties and provide the coupled capabilities with arbitrary polygonal face meshes at the truncation boundaries of numerical models. Then, a complex stretching function from PML is applied to radial direction of the local scaled boundary coordinates to map the physical space onto the complex space, resulting in a SBPML domain. Upon spatial discretization, the proposed method is formulated using a 2nd-order mixed displacement-stress unsplit-field formulation, allowing seamless coupling with FEM and SBFEM originally designed for the interior computational domain. Finally, three benchmark examples of wave propagation problems in unbounded domains and two soil-structure interaction problems of engineering problems are presented to demonstrate the accuracy and robustness of the Prismatic-element SBPML. [ABSTRACT FROM AUTHOR]

In this paper, a novel direct time-domain numerical method, called the FEM-SBFEM-SBPML, is proposed to study the wave propagation problems in soil-structure interaction (SSI) system with complex geometry and geological condition. In the bounded domain, the structure is modeled as beam element based on the finite element method (FEM), and the surrounding truncated soil is discretized using the scaled boundary finite element method (SBFEM) combined with an efficient quadtree mesh generation technique, respectively. In addition, a solid-modified beam coupling model considering the eccentric effect of the tangential traction at the outer surface of the structures is implemented. The unbounded domain is modeled by a recently proposed scaled boundary perfectly matched layer (SBPML) method, which is a novel high-accuracy absorbing layer method satisfying the radiation condition. As a result, the combined FEM-SBFEM-SBPML approach is capable of modeling SSI with complex geometries and soil properties automatically. Some benchmark tests are conducted to illustrate the accuracy and efficiency of the proposed scheme, and a vibration analysis of a soil-tunnel system is further presented to demonstrate the applicability of the proposed method in engineering. [ABSTRACT FROM AUTHOR]

Artificial boundary method is widely used in the numerical modeling of unbounded wave problem. However, the accurate modeling of truncated infinite domain with general geometry and heterogeneous materials is still a challenging task, especially for direct time-domain analysis in three dimensions (3D). In this paper, a novel 3D time-domain artificial boundary method, called Scaled Boundary Perfectly Matched Layer (SBPML), is proposed. This method is a generalization of the Perfectly Matched Layer (PML) based on a scaled boundary coordinates transformation inspired by the Scaled Boundary Finite Element Method (SBFEM), which is capable of using artificial boundary of general geometry (not necessarily convex) and considering plane physical surfaces and interfaces extending to infinity in the truncated infinite domain. Local scaled boundary coordinates are firstly introduced on the element-level into the truncated infinite domain to describe general geometry properties of the infinite domain. Then, a complex stretching function from PML is applied to radial direction of the local scaled boundary coordinates to map the physical space onto the complex space, resulting in a SBPML domain. The spatial discretization of the SBPML domain produces semi-discrete mixed displacement–stress​ unsplit-field formulations of third orders in time. The order of the obtained formulation can be reduced by one, enabling a seamless coupling with the standard displacement-based finite element formulation of the interior domain. The coupled system can be solved by an explicit time integration algorithm efficiently. The validation of the SBPML is demonstrated through several benchmark tests, including wave problems in unbounded domains with general geometries and heterogeneous material properties. Furthermore, the application of the SBPML in dynamic soil–structure interaction (SSI) is demonstrated using two engineering problems, including an impact analysis of soft rock-nuclear island system and a vibration analysis of soil-lined tunnel system. • Novel time-domain 3D Scaled Boundary Perfectly Matched Layer (SBPML). • Capability to model general-shaped infinite domain with extending interfaces. • Seamless coupling with existing explicit FEM codes. • Validation and application studies involving complex engineering problems. [ABSTRACT FROM AUTHOR]

We present, for the first time, the application of explicit time-stepping schemes within the context of the scaled boundary finite element method (SBFEM). To this end, we discuss in detail how and under which circumstances diagonal mass matrices can be obtained. In addition, we propose an approach to improving the interpolation accuracy of quadratic scaled boundary-shape functions. In essence, our results show that mass lumping can be achieved without loss of accuracy if linear or quadratic node-based shape functions are deployed for the interpolation on the subdomain boundaries. This finding also applies to non-convex elements, which allow coarse discretizations — and, hence, comparably large time steps — in problems involving singularities. We discuss the application to polygonal and severely distorted meshes. Numerical examples include problems from the fields of acoustics, elasticity, and thermal diffusion. • First comprehensive discussion of explicit dynamics in the context of the SBFEM. • Mass lumping is achieved without loss of accuracy for polygonal elements. • Improved convergence by enrichment and blending. • Accurate results in wave propagation simulations on highly distorted meshes. • Singular problems are solved without excessive mesh refinement. [ABSTRACT FROM AUTHOR]

This paper presents an efficient numerical framework for the seismic analysis of post-tensioned concrete gravity dams, which automatically inserts anchors into the structure. The proposed approach is implemented in the commercial finite element software ABAQUS by introducing a polygonal user element (UEL) derived by the scaled boundary finite element method (SBFEM). By inserting nodes in the polygonal structural mesh along the anchor layouts, duplicating the inserted nodes representing anchors, and generating cohesive elements on the node pairs, post-tensioned anchors are naturally embedded into the structure, and the bond–slip interactions are considered. Furthermore, an unbounded UEL derived by the SBFEM is implemented to simulate the unbounded foundation in the dam–reservoir–foundation interaction systems. The unbounded UEL only requires a small truncation area around the region of interest to rigorously capture the dynamic properties of the infinite foundation in terms of a displacement unit-impulse response. This ABAQUS implementation allows the use of built-in capabilities of ABAQUS for nonlinear dynamic analysis, including contact modeling and cohesive fracture. Weak structural interfaces existing in a concrete gravity dam (dam–foundation interface and construction joints) are modeled by a cohesive–frictional contact scheme. In the end, sophisticated numerical models dams featuring post-tensioned gravity dams with weak interfaces and anchors can be generated in a fully automatic manner, requiring no special treatments for mesh generation such as partitioning. The accuracy of the proposed technique is verified through a numerical example of the Manly dam strengthened by a vertical anchor. The efficiency of this approach is demonstrated through a dam with three construction joints anchored by multiple inclined anchors. The input files of the numerical examples are available from the authors upon request. • A novel procedure for embedding anchors in conforming polygon mesh. • A node-to-node scheme combining cohesive elements and frictional contacts. • Effectively modeling of bond–slip of anchors and weak interfaces. • Implementation of polygon UEL and unbounded domain UEL in Abaqus. • Dam–reservoir–foundation interaction with anchor pull-out and interface failure. [ABSTRACT FROM AUTHOR]

• Proposes an extension of the SBFEM to treat implicitly defined interfaces in two and three dimensions. • Does not require enrichment functions and/or special numerical integration techniques. • Does not require additional elements on the interface boundaries. • Yields optimal convergence rates in L 2 norm and H 1 seminorm. In this paper, the scaled boundary finite element method (SBFEM) is extended to solve the second order elliptic equation with discontinuous coefficients and to treat weak discontinuities. The salient feature of the proposed technique is that: (a) it requires only the boundary to be discretized and (b) does not require the interface to be discretized. The internal boundaries are represented implicitly by the level set method and the zero level sets are used to identify the different regions. In the regions containing the interface, edges along the boundary are assigned different material properties based on their location with respect to the zero level set. A detailed discussion is provided on the implementation aspects, followed by a few example problems in both two and three dimensions to show the robustness, accuracy and effectiveness of the proposed approach in modelling materials with interfaces. The proposed technique can easily be integrated to any existing finite element code. [ABSTRACT FROM AUTHOR]