“…Usually these methods are based on the use of the special finite elements derived to simulate the impenetrability condition between two surfaces (Wriggers and Imhof, 1993;Wriggers, 2002). On the other hand, the unilateral constraints can be maintained in the formulation, retaining the original philosophy of the problem, and an alternative linear complementary problems (LCPs) can be obtained and solved by, for example, Lemke's or Dantig's algorithms (Lemke, 1968;Ascione and Grimaldi, 1984;Joo and Kwak, 1986;Barbosa, 1986;Silveira, 1995;Koo and Kwak, 1996;Silva, 1998;Silva et al, 2001;Wriggers, 2002;Pereira, 2003;Holanda and Gonc ßalves, 2003).…”