U.S.-Denmark Cooperative Research on Damage Evolutions and their Sensitivities during Metal Forming Process

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This award supports Abhijit Chandra of the University of Arizona to collaborate in materials engineering research with Viggo Tvergaard of the Department of Solid Mechanics of the Technical University of Denmark. They share an interest in the forming of metal and in understanding the processes that affect the properties of the finished product. In particular, their collaborative research focuses on understanding the phenomenon of local instabilities generated by interactions of microdefects in a damage cluster. Professor Tvergaard has developed various models for damage evolutions in situations involving plasticity and creep. Professor Chandra has worked extensively on metal forming processes and on design sensitivities of these processes. This complementary expertise is combined very effectively in the proposed collaborative research plan. During a metal forming process, the workpiece material is subjected to intense stress and deformation fields. As a result, the material undergoes large plastic strains and rotations in order to produce new and desirable shapes of the workpiece. However, the stress and deformation fields may cause local instabilities that may nucleate microscopic voids. Growth of such defects results in degradation of the mechanical properties of the finished product, and may even lead to its failure. The results of the proposed research will be very helpful in designing forming processes that avoid or minimize the development of this damage in the workpiece.