Critical states of thin underlayers under tensile afford

Mathematical models of the stress state of plastic layers (interlayers) under the tensile load under plane deformation are investigated. The layer of rectangular shape is included in the strip of more durable material. The method of characteristics (slip lines) is used. The reasons that contact hardening is not fully realized are investigated. The characteristic fields in the layer in the process of loading are analyzed. The classification of characteristic fields at the critical moment of loading is given. The criterion for the full realization of contact hardening of the layer material is obtained. It depends on the relative thickness of the layer and the coefficient of mechanical heterogeneity of the joint. Explicit analytical expressions for calculating the critical load in the case of the full implementation of contact hardening are obtained.