Three-dimensional plate and contact/friction elements for laminated composite joints

A contact/friction isoparametric finite element for the analysis of connections between laminated composite plates is presented. The element is compatible with a three-dimensional plate element based on layer-wise constant shear theory. The contact/friction element is based on a simple regularization of the unilateral contact with an orthotropic Coulomb friction problem. Two different friction coefficients in orthogonal directions and a constitutive law to model slip in any direction are used to account for the orthotropic surface texture of fiber-reinforced materials. The contact and friction constitutive law is distributed over the entire surface in contact/friction. The integration scheme is chosen to accurately account for the partial contact and slip inside the element, thus avoiding unnecessary mesh refinement. Unlike nodal gap elements, the proposed element applies the contact and friction constitutive laws uniformly over the contact/friction surface regardless of mesh refinement or element distortion. The irreversibility of the process leads to unsymmetric secant stiffness matrix. However, an iterative procedure working on symmetric matrices is proposed. Finally, numerical results are presented. © 1995.