bimaterial fracture mechanics

Dear all,

I am improving the cohesive zone model in 2-D proposed by Y.F. Gao to simulate delamination between sub-micron thick films in 3-D. However, I did not find the potential function proposed by Xu and Needleman in 3-D. If you know it please tell me

Here is the potential function proposed by of Xu and Needleman in 2-D (in Y.F Gao’s paper)

Hello every body,

As most of you know, fracture mechanics of polymer materials needs a special consideration of the viscoelastic material properties. Especially under thermomechanical loading the role of glass transition temperature T_g is very important. That is why people try to characterize the material with different methods including stress relaxation based on Time-Temperature superposition or DMA test.