Mechanisms of Microstructural Influences on Cyclic Plasticity and Ratchetting

这个项目是研究在材料循环变形的情况下晶体织构变化的影响。对于单调载荷，这些效应已经得到了广泛的研究，但对于循环变形，人们的理解却很差。这种认识的缺乏通常会影响裂纹起裂模型以及裂纹扩展和失效评估。晶粒尺寸和织构在位错亚结构中起着重要的作用，它们的相互作用决定了金属中的残余应力。在这个项目中，将研究镍单晶的建模和实验相结合的方案。利用该数据库，将建立包括非均匀晶粒子结构在内的显式多晶模型，研究晶粒尺寸和织构对循环塑性和棘轮型加载历史中背应力的影响。＊＊＊

9634707 Moosbrugger This project is to study the effect of a changing crystallographic texture in the case of cyclic material deformations. For monotonic loadings these effects have been studied extensively, but for cyclic deformations the understanding is poor. This lack of understanding affects crack initiation models as well as crack growth and failure evaluations in general. Grain size and texture play important roles in the dislocation substructures and their interactions determine the residual stresses in metals. In this project a combined modeling and experimental program will be studied in nickel single crystals. With this data base, explicit polycrystalline models including heterogeneous grain substructure will be built to study the influence of grain size and texture on back stress in cyclic plasticity and ratchetting type loading histories. ***