[An incremental constitutive law for ageing viscoelastic materials: a three-dimensional approach] : Une formulation incrémentale tridimensionnelle pour les matériaux viscoélastiques vieillissants

Abstract : A new approach to a viscoelastic medium is presented and the constitutive equations of ageing viscoelastic materials are developed. The formulation is equivalent to ageing Kelvin or Maxwell chain models with age dependent elastic moduli and viscosities. It is shown that by using such models, the retaining of the complete past history of stress and strain in the memory of a digital computer is avoided. Finally, the formulation is generalized to deal with three-dimensional problems.