VEROAD: A Viscoelastic Multilayer Computer Program

Abstract

The mathematical principles and derivation of a linear viscoelastic multilayer computer program are described. The principles of the derivation apply equally to conventional linear elastic programs. The practical consequences of the viscous material properties for the mathematical derivation have been solved by Fourier transformation; another mathematical consequence is that complex calculus was inevitable. The program is called VEROAD, (viscoelastic road analysis Delft). The program's primary extension is that the analyzed material can be vis-coelastic. Consequences of this extension are numerous: calculation from physical material properties of quantities such as time-dependent displacements, stresses and strains, permanent deformations, and dissipated energies is made possible. All these quantities depend on velocity of traffic, which is explicitly included in the calculations. The material model assumes the bulk modulus to be elastic and the shear modulus to be viscoelastic. The latter follows Burger's model. For illustrative purposes some mechanical analyses of asphaltic road structures are carried out, with emphasis on the distribution of stresses, strains, (permanent) deformations, and dissipated energies.