Effect of Rheological Behavior on Thermal Stresses

Since the conventional elastic analysis of thermal stress problems coupled with limiting creep rates and time-dependent fracture stresses as (inelastic) design criteria, results in design procedures for thermal stresses (in heat exchangers, nuclear reactors, flight structures at supersonic speeds, etc.) of considerable unreality, the effect of various types of rheological behavior (viscoelastic, plastic, work hardening) on the level of thermal stresses is analyzed under simplified assumptions, such as uniaxial stress and polar or cylindrical symmetry. The effect on the thermal stress intensity of the rheological behavior of the material is shown to be very significant, particularly with respect to stress relaxation and the development of residual stresses.