Viscoplastic intimate contact process of uneven surfaces is numerically studied by using the finite element model proposed in our previous paper. The model treats only the case that the interfacial contact is the rate determining step of the solid state bonding process. The distribution of the equivalent strain rate around the void surface is strongly influenced by the bulk constraint conditions, i.e., the interfacial deformation is greatly affected by the bulk deformation. The strain rate at the void tip is strikingly increased by the bulk deformation, which accelerates the void shrinkage on the bond interface. If the bulk is deformed, the contacting process is also affected by the asperity angle α0 due to surface waviness. When α0 < 30 deg, the bonded area growth is mainly produced by the folding phenomena of the faying surfaces.
Takahashi YY, Koguchi TT, Nishiguchi KK. Effect of Bulk Deformation on Viscoplastic Adhering Process—A Numerical Study of Solid State Pressure Welding. ASME. J. Eng. Mater. Technol. 1993;115(2):171-178. doi:10.1115/1.2904203.