An SBFEM Approach for Rate-Dependent Inelasticity with Application to Image-Based Analysis

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.