Tact: A Contact Analysis Program

Abstract

The computer analysis program TACT is applicable to wide classes of problems of solid and fluid thermomechanics and in particular to dry and lubricated contact-impact problems. The program can be utilized to solve one-, two- and three-dimensional problems which may be linear or nonlinear, steady state or transient. Both small and large deformation (total Lagrangean) formulations are available for the modelisation of solids as well as a spatial description (Eulerian) for liquids. Material laws include linear elastic, nonlinear elastic (rubber) and elastic-plastic (Von Mises) models for solids and linear viscous (Newtonian) liquids.

Both small and large gap and slip simulations are possible, along contact surfaces. Interface laws include adherence (stick), sliding (slip) and nonassociated (Coulomb’s) friction. Lubricants are separately treated as a third body.

The program is based on the finite element method for the spatial discretization, successive linearizations to overcome the non-linearities and on a choice of finite difference schemes for the time integration. The penalty and the duality methods are used for dry contacts with special impact-release conditions in dynamics. The friction algorithm is directly inspired from the radial return algorithm of plasticity, with a consistently derived nonsymmetric tangent matrix.