Modelling of Multi-Material Assemblies using an Equivalent Finite Element

Abstract

The aim of the present work is to develop a methodology which allow us to simplify an assembly point, and keeping a realist physical behaviour, in addition to reduce the time of calculation of numerical simulations. Indeed, the study of the structure by a three-dimensional finite element, taking into account the problem of nonlinearities (behaviour and contact) increase the time of calculation and require large size of memory. Likewise, the optimization of the assembly (number and position of the points) leads to an important number of calculations. Therefore it is absolutely necessary to reduce the time of each numerical simulation. The classical method of simplification consisted to replace the assembly point by a simple rigid connector, in many cases this method don’t present the behaviour of point and can cause significant errors in the global response, or local behaviour. Several studies exist in the literature but they do not apply to multi-material assemblies or they require specific elements whose it is not feasible to apply it in an industrial code. In this paper, we propose a simple and nonlinear finite element model that responds to industrial requirement. This model is an equivalent element (connector) that creates a connection between two nodes; this type of connector is available in many industrial codes. So the difficulty is to determine its mechanical behaviour, taking into account the geometrical and materials parameters, which is based on experimental tests. We will show the feasibility of this approach. Another important problem need to study is to modeling the location of plastic strain and damage in the contact area, where this location leads to embrittlement of structures and pilots their mechanical ruin. So we will study the local stress in the critical points of assembly by a post-treatment of finite element solution.