Energy‐based time derivative damage accumulation model under uniaxial and multiaxial random loadings

Abstract

A new fatigue life prediction method using the energy-based approach under uniaxial and multiaxial random loadings is proposed. The uniqueness of the proposed model is based on a time-derivative damage accumulation unlike classical cycle-based damage accumulation models. Thus, damage under arbitrary random loading can be directly obtained using time-domain integration without cycle counting. First, a brief review of existing models is given focusing on their applicability to uniaxial/multiaxial, constant/random, and high cycle fatigue/low cycle fatigue loading regimes. Next, formulation of timederivative damage model is discussed in detail under uniaxial random loadings. Then, an equivalent energy concept for general multiaxial loading conditions is used to convert the random multiaxial loading to an equivalent random uniaxial loading, where the time-derivative damage model can be used. Finally, the proposed model is validated with extensive experimental data from open literature and in-house testing under various constant and random spectrum loadings.

Parameter estimation in multiaxial fatigue short crack growth model using hierarchical Bayesian linear regression

“…In addition, notches in the structures or other geometric changes can also cause local parts to be in a multiaxial stress state 4 . Research on fatigue characteristics of structures under multiaxial loads has grown up to be a hot spot for researchers 5,6 …”

“…4 Research on fatigue characteristics of structures under multiaxial loads has grown up to be a hot spot for researchers. 5,6 Some researchers described multiaxial fatigue crack growth based on fracture mechanics. Erdogan and Sih 7 studied the crack growth behavior under multiaxial loads in Modes I and II.…”