Verifying the Movable Elastoplastic Boundary Method by Using Galin’s Problem

Galin’s solution for the problem of biaxial tension of a plate with a hole completely covered by the plastic region appears to be a pearl recognized by the world scientific community. This solution serves as a test for all sorts of approximate approaches to solving elastoplastic problems, including the semi-analytical iterative method being developed by the author, focused on solving more complex problems such as the Kirsch problem in the elastoplastic formulation. The proposed iterative approach for a semi-analytical solution involves an explicit analytical expression for stresses in the plastic region and an iterative numerical solution in the elastic region with a refined border. The paper shows the convergence of the results based on the iterative procedure for the elastoplastic region boundary approaching its analytical position, which follows from the analytical solution of Galin’s elastoplastic problem. Consideration has also been given to obtaining results on the determination of the boundary between the elastic and plastic regions using a competing approximate perturbation method. The advantage of the proposed method lays in not limited modifications in parameters due to the requirement for small differences while formulating a problem from the axisymmetric case as seen in the perturbation method.

Диагностика остаточных напряжений в биметаллических пластинах алюминий-сталь с использованием лазерного ультразвука и зондирующего отверстия

The character of changes in laser photoacoustic signals near small-diameter holes in layers of aluminum and steel in a bimetallic plate obtained by hot rolling is investigated. The experimental results are compared with the solution of the classical Kirsch problem for stress distribution around a circular hole in a prestressed material. The possibility of assessing internal stresses by a laser photoacoustics in combination with the hole drilling method in industrial bimetallic plates is shown.