A SUPERSTABLE TIME-DISCRETE SCHEME FOR THE NUMERICAL-INTEGRATION OF VISCOUS CONSTITUTIVE-EQUATIONS

The general framework of the paper deals with the finite element model ling of mechanical problems involving viscous materials such as bitume n or bituminous concrete. Its aim is to present a second-order-accurat e discrete scheme which remains unconditionally superstable when used for the time discretization of the linear and non-linear viscoelastic constitutive equations considered. After stating the space- and time-c ontinuous mechanical problem we focus on the time discretization of th ese equations, considering three different schemes. For both of them s ufficiently small values of the time step are required in order to ens ure the superstability, whereas the third remains unconditionally supe rstable. Eventually, some numerical results are presented. (C) 1998 Jo hn Whey & Sons, Ltd.