Cyclic inelastic behavior and shakedown response of a 2nd generation nickel-base single crystal superalloy under tension-torsion loadings: Experiments and simulations

Abstract

Nickel-base single crystal superalloy components are designed to experience extreme and often cyclic multiaxial loads. While much of the literature has provided the foundation to use these materials near critical yield conditions, their use under inelastic design, exploiting safe elastoplastic shakedown behaviors is largely unexplored. In particular, this paper focuses on establishing the conditions for the macroscopic shakedown response of a 2nd generation nickel-base superalloy under tension-torsion loadings from numerical and experimental perspectives. A numerical model is developed to more broadly evaluate shakedown limit loads and it is found that by allowing shakedown to occur, an 18% increase in feasible design load space is expected compared to traditional first-yield design criteria. Experiments on hollow cylindrical specimens are also conducted and used to assess the prediction capabilities of the numerical finite element model.