Abstract:

The residual stress around a coldworked hole is computed with elasto-plastic finite element methods of both flow theory and deformation theory. It is shown that: when M is small, for Alalloy LY12CZ, M≤2%, where M is defined as (Dmandre.-Dhole)/Dhole×100%, both of the two tneories can be used; when M is not small, for AI alloy, M>2%, the result of the former method fits with the boundary condition, but the latter theory is not. The initiate lives of super strength steel 30 CrMnSiNi 2 A plate with a coldworked hole are calculated by using the residual stress obtained with both of the two methods. It is shown that, the former result fits with the experimental result, but the latter is not. For the process of coldworking hole, M is generally not small, therefore deformation theory is fit for computing the residual stress around a coldworked fastener hole.

Key words: deformation theory, flow theory, coldworked hole