The damage behavior of an aluminum-composite hybrid beam under three point bending loading was investigated by a finite element analysis (FEA). An aluminum square hollow section beam wrapped by four plies of unidirectional carbon fiber reinforced plastic (CFRP) with a designed stacking sequence was investigated. Nonlinear elasto-plasticity and progressive damage mechanics were applied for aluminum and CFRP, respectively. Hashin's damage initiation criteria and energy based damage evolution were applied. Delamination and debonding were modeled by a cohesive zone model defined by the traction separation law and an energy based damage evolution scheme. For a numerical analysis, material properties of the aluminum, failure characteristics of the CFRP laminate, and adhesion between the aluminum and CFRP were measured experimentally.
The FEA showed that stress was concentrated at the edges under the loading nose. It was observed that the lay-up sequence of the laminates strongly influenced the performance. At low bending loading, failure of CFRP and delamination over a small area just below the loading nose occurred. As the load increased, the interface between aluminum and CFRP was debonded. Plastic buckling of aluminum and bending collapse behavior of the hybrid beam then occurred upon further loading. Overall performance of the hybrid beam represented by load-displacement curves with respect to the stacking sequence of the laminate was compared with experimental results. The FEA showed good agreement with the experimental results.