LAUSR

Abstract The present contribution is dedicated to a coupling method mixing finite and discrete elements to simulate thermally induced stresses and local damage in composites. Investigations are focused on ceramic-metal materials which are characterized by a strong difference of properties and a coefficient of thermal expansion mismatch. Typically, thermal residual stresses are induced at the interface during a cooling process which can lead to dramatic effects on the local integrity of the joint. Some discrete approaches as the lattice beam model enable to simulate such effects but in some cases lead to prohibitive calculation costs which affect their relevance. As a result, a coupling method taking benefit of both continuous and discrete approaches with a lower computational cost is of great interest. In this work, we investigate the DEM-FEM coupling approach based on a domain decomposition with overlapping area which has already proved its flexibility and its reliability in a large context. However, be aware that what is commonly called DEM-FEM coupling is in fact a beam lattice-FEM coupling approach in which the lattice network is generated using the contact network of a granular assembly. Preliminary studies are first carried out to verify the ability of the coupling method to take into account the thermal expansion in homogeneous medium. In a second step, tests are performed in the framework of ceramic-metal fiber composites and compared to FE simulations in terms of stress and strain fields. Interfacial debonding effects are also studied. Finally, a classical ceramic-metal joint issue with local damage is simulated. In each case, results exhibit the relevance of the present approach to take into account thermal expansion and damage with a suitable accuracy. They also show a significant computation time decrease compared to FEM and DEM.