Novel Discrete Multiscale Model (DM) for non-linear analysis in composite materials

Abstract

In recent years, the study of the behavior of materials at the microscopic level has increased significantly in terms of design of high-performance materials. Despite recent advances in high-performance computers, the application of multiscale numerical methods to simulate large structures still requires prohibitive computational costs. The purpose of this work is to provide a procedure capable to predict the nonlinear mechanical response of composite materials under monotonic incremental load to reduce the computational cost required for the numerical analysis of complex structures. The solution of the macroscopic problem through the first order multiscale method (FE2) will be replaced by a Discrete Multiscale Model (DM) characteristic of the Representative Volume Element (RVE). Through the definitions of an equivalent damage parameter (deq), function of the global stress at the microscale, a series of virtual tests in deformation control will be carried out, storing the stress-strain state reached by certain levels of deq in a Database. Analyzing the evolution of the fracture in the composite materials can be observed as the non-linear regime is reached only in some elements of the structure. Therefore, a procedure, the Discrete Multiscale Threshold Surface (DMTS), in which the RVE analysis is used to obtain the surface at which the damage begins (deq>0) is proposed. This law allows to know if for a certain stress-strain state the material has damaged, without needing to solve the micro-model. Once the damage is initiated, it is proposed to generate an RVE only at the integration points that have been damaged. This work will demonstrate how the FE2 method can be replaced by a Discrete Multiscale Model, representative of the composite material, obtaining significant computational improvements.

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