Cohesive Modeling of the Deformation and Fracture of Weld- bonded Joints

Cohesive Modeling of the Deformation and Fracture of Weldbonded Joints M. N. Cavalli, M.D. Thouless and Q.D. Yang Mechanical Engineering Department Materials Science and Engineering Department University of Michigan Ann Arbor, MI Rockwell Scientific Company Thousand Oaks, CA Abstract In previous work, cohesive-zone models have been developed separately for the analysis of adhesively-bonded joints and for the analysis of spot-welded joints. The appropriate fracture parameters have been determined for a commercial rubber-toughened epoxy bonding thin sheets of a 5754 aluminum alloy. They have also been determined for spot welds formed under specific processing conditions in this same alloy. It has been established that these parameters provide an excellent predictive capability for design, in the sense that loads, deformation and energy absorption can be accurately predicted for different geometries of joints bonded under nominally identical conditions. In the present paper, these two separate models are combined to provide a design tool for weld-bonding in which adhesive technology is combined with spot welding. It is demonstrated that the models developed separately for the two joining techniques can be combined and used with no further modification to predict accurately the behavior of weld-bonded geometries. In particular, strength and energy-absorption characteristics of a joint from initial loading through final failure are correctly captured, regardless of the joint geometry tested.