A Reduced Order Constitutive Modeling Approach for a Material Subjected to Combined Cycle Fatigue

摘要

As the plans of next generation hypersonic vehicles are drafted, material selection for key components is a critical step in the design process. The service conditions, however, are expected to be more aggressive than those to which many materials have been exposed to in laboratory conditions. For example, key fuselage panels will experience super-imposed thermal, mechanical, and acoustical loading. Despite the more recent efforts to characterize materials under these so-called combined extreme environments (CEEs), the temperature-and rate-dependent cylic hardening/softening responses are still relatively under-characterized. A method to develop first approximations of constitutive model/parameters for materials under extreme service conditions is presented. The method is exercised on IN617 a Ni-base alloy often employed for high temperature applications. The approach shows that a minimal collection of tensile, creep, and LCF data are needed to develop predictions of materials under thermos-acousto-mechanical fatigue loading.