Papers by Keyword: Dual Boundary Element Method

Abstract: The purpose of this paper is to solve dynamic fracture problems of plates under both tension and bending using the boundary element method (BEM). The dynamic problems were solved in the Laplace-transform domain, which avoided the calculation of the domain integrals resulting from the inertial terms. The dual boundary element method, in which both displacement and traction boundary integral equations are utilized, was applied to the modelling of cracks. The dynamic fracture analysis of a plate under combined tension and bending loads was conducted using the BEM formulations for the generalized plane stress theory and Mindlin plate bending theory. Dynamic stress intensity factors were estimated based on the crack opening displacements.

Abstract: The aim of this paper was to carry out numerical simulations of structural health monitoring applications for plate structures using the boundary element method (BEM). The fundamental symmetric Lamb mode (S0) is chosen for the SHM applications. The propagation, reflection and diffraction of the S0 mode Lamb wave are modelled using a boundary element formulation based on the plane stress theory. Piezoelectric (PZT) actuators are mounted on plate surfaces to excite the S0 mode wave. A semi-analytical method is adopted to couple the PZT actuators and the host plate. Numerical results show that BEM is a very efficient simulation method for the structural health monitoring of plates.

Abstract: In this paper, the application of the dual boundary element method (DBEM) in the field of structural health monitoring (SHM) is explored. The model involves a 3D host structure, which is formulated by the DBEM in the Laplace domain, and 3D piezoelectric transducers, whose finite element model is derived from the electro-mechanical behaviour of piezoelectricity. The piezoelectric transducers and the host structure are coupled together via BEM variables. The practicability of this method in active sensing applications is demonstrated through comparisons with established FEM and parametric studies.

Abstract: In this paper, a boundary element method (BEM) for the time-harmonic analysis of electromechanically (EM) coupled 3D structures is presented. Among the two components of an EM coupled structure, the piezoelectric transducer is modelled by a semi-analytical finite element method (FEM), and the host structure is formulated by the dual boundary element method (DBEM). The analysis of the coupled structure is performed in the Fourier domain. The electromechanical impedance (EMI) of the system is used for the purpose of detecting damages.

Abstract: This paper presents a new fatigue crack growth prediction by using the dimensional reduction methods including the dual boundary element method (DBEM) and element-free Galerkin method (EFGM) for two dimensional elastostatic problems. One crack extension segment, i.e. a segment of arc, is introduced to model crack growth path. Based on the maximum principle stress criterion, this new prediction procedure ensures that the crack growth is smooth everywhere except the initial growth and the stress intensity factor of mode II is zero for each crack extension. It is found that the analyses of crack paths using coarse/large size of crack extension are in excellent agreement with analyses of the crack paths by the tangential method with very small increments of crack extension.

Abstract: The efficient solution of the 3D crack surface contact problem utilizing the boundary element method (BEM) is presented. The dual discontinuity method (DDM), a special formulation of the BEM, is applied. This method deals directly with the relative displacements and the discontinuities of the tractions at the crack. For the normal behavior a unilateral contact is assumed and for the description of the tangential behavior Coulomb’s frictional law is utilized. The hard contact formulation is regularized by the application of the penalty method. An incremental iterative procedure based on a radial return mapping algorithm is applied for the solution of this non-linear problem. Based on the stress field the fracture mechanical parameters are determined by an extrapolation method for all increments of a characteristic load cycle. By the analysis of this load cycle the cyclic fracture mechanics values are obtained. Due to the non-linear nature of crack growth the simulation is implemented in the framework of a predictor-corrector scheme. For the investigation of the influence of the crack surface roughness on the behavior of cracks two numerical examples are presented.

Abstract: This paper presents the geometrically nonlinear analysis of cracked plates by the dual boundary element method. Extrapolation of displacements on the crack surfaces is used to compute the stress intensity factors. The normalized stress intensity factors for the cracked square plate with fully clamped and simply supported boundary conditions are presented.