7. Viscoelasticity

This chapter describes the input syntax of viscoelasticity models. For theoretical backgrounds see Chapter 19. Three viscoelastic models are available: Power Law, Maxwell Chain and Kelvin Chain. The general form for both Chain models is the direct input, but indirect input is available for some applications. Indirect input involves diagrams for creep and relaxation or specific concrete creep functions [§7.4]. DIANA will automatically translate indirect input to direct input during the evaluation of the elements and their properties. User-specified direct input overrules any form of indirect input for the current material index. Viscoelasticity cannot be combined with orthotropic material.