Numerical Study on Yield Curves of FCC Metals Based on Rate-Dependent Crystal Slips

Capturing the influence of surface constraints in small and thin samples using polycrystalline plasticity theory

“…The predictions offered by the incremental upper and lower bound models typically encompass a large regime and researchers have attempted to improve the predictive capability of polycrystalline plasticity models by deriving more accurate assumptions about the stress-strain distributions within a polycrystal. Many are variations of the original Sachs or Taylor-Bishop and Hill assumptions, as noted by Prantil et al [13] and Abe et al [14]. Another approach to computing the composite response of a polycrystalline aggregate, referred to as the self-consistent method, has been derived from Eshelby's equations based on an ellipsoidal inclusion in a continuous medium [15][16][17].…”

On the Relation between R-Value of a Grain and the Operating Slip Systems of the Grain

“…In the previous paper [6,7] , the relation between the shape of yield curve and the number of active slip systems for fcc and bcc metals was analyzed. The relation between the shape of yield curves and the number of active slip systems was clarified.…”

“…g represents a function describing strain hardening and a is a parameter related of the shear strain rate. It was shown [6,7] that, by changing the value of m , the effects of the number of the active slip systems is studied.…”

“…On the other hand, it was shown that by using a rate-type constitutive relation for crystal slips the effect of the number of active slip systems on the yield curves is clarified [6,7]. The rate-sensitivity exponent in the rate-type constitutive relation is closely related to the number of active slip systems.…”