A micro-macro finite element model for failure prediction of ComeldTM joints

A micro-macro mechanical finite element model is developed for the prediction of the ultimate strength and failure modes of Composite-Metal-Weld (Comeld) joints. A micromechanical finite element model is firstly proposed, based on the periodic RVE technique, to gain the equivalent stiffness and strength of the protrusion layer by FEM. A suitable unit cell model, which can represent the protrusion layer through applying a unified periodical displacement boundary condition, has been established according to the geometric distribution of protrusions on the metal surface. With the predicted equivalent properties of the protrusion layer which can be considered as a new homogenized material layer in the global model, failure modes and ultimate strength of three different Comeld joints subjected to static tensile loads are predicted numerically. A good agreement between the experimental and simulated results shows correctness and effectiveness of the developed micro-macro mechanical method for predicting the load bearing capacity of Comeld joints. Moreover, Comeld parameters like the density and height of protrusions and the lap size of joints need to be adjusted to achieve higher joint strength.