Modeling large number of rod-to-rod and rod-to-rigid surface frictional contact

In many engineering systems such as nuclear fuel rods and heat exchangers tubes, mechanical components are subjected to a large number of frictional-contact constraints. An efficient and robust numerical scheme is needed for handling such a number of constraints. In this paper a numerical method is developed and presented to handle a large number of rod-to-rod and rod-to-rigid frictional contact constraints. New auxiliary incremental displacement variables are defined and the non-linear frictional-contact problem is formulated to be a linear complementarity problem (LCP). Use of LCP eliminate the need for iteration and satisfies all the frictional contact constraints in the whole system simultaneously. The mixed three-node beam finite elements are employed to model the longitudinal and lateral deformation of rods. The equations of motion of the entire dynamical system are discretized in the time-domain by means of the Bozzak-Newmark scheme. Validation cases are discussed and numerical results were obtained and presented for an array of 37 rods inside a tube.