On the unloading process for contact interaction
The unloading process in a body under the action of a stamp is investigated. It is assumed that the unloading occurs at all points of the body. The contact area between the body and the stamp can change during the unloading; consequently, the unloading problem during contact interaction is nonlinear. A generalization to the case of contact problems is proposed for the theorem of unloading. A variational principle is obtained in the unloading displacements, and the existence and uniqueness of the solution of the unloading problem are investigated. The unloading process is examined in an elastic-plastic half-space on which a stamp of circular planform acts. The change in the contact area and in the contact stresses during unloading is studied, and the shape of the residual impression is obtained. The problem is investigated by using the Galin solution of the action of a circular stamp and a load applied outside the stamp on an elastic half-space. Numerical methods of solving contact problems with unloading are also examined; an example is presented for the numerical solution of the problem of plane deformation in the compression of a strip by two stamps with subsequent unloading.
scientific article; zbMATH DE number 3968090