Elastic-plastic unilateral contact problems for slackened systems

The paper deals with the mathematical modelling of a class of unilateral elastic-plastic contact problems. The problem is posed in the framework of the so-called slackened systems. The considerations are confined to small strains and piecewise linear approximations of the yield surface and the clearance surface. An incremental formulation is proposed in the form of a linear complementarity problem (LCP). The formulation allows one to analyse a structural system which can be subjected to nonproportional loading paths. The included numerical results illustrate the application of this formulation to an elastic-plastic beam that comes into contact with a unilateral elastic-plastic foundation.