Papers by Author: Z.F. Yue

Abstract: Two kinds of representative volume elements (RVEs) are introduced to represent the experimental γ/γ′ morphology to study the influences of microstructures on the creep behavior of [0 0 1]-oriented single crystal nickel-based superalloys under tensile loading. One RVE (RVE1) is consisted with one cuboidal γ′ phase surrounded by γ phase. The other (RVE2) is constructed by two cuboidal γ′ phases and one rectangle γ′ phase. A raft criterion is implemented into a user subroutine to predict the rafting type. The misfit stress is considered by different thermal expansion coefficients of the two phases. The rafting type is correctly predicted. The evolutions of the stresses distributions are discussed.

Abstract: In this paper, four axisymmetrical finite element models have been established to study effect of thinckness on residual stress fields of cold expansion hole, experiments were carried out to measure the residual stress of cold expansion hole and verify simulation results. The experiment results also show that cold expansion processing can decrease surface roughness of holes and improve surface quality. The FEM results show, at the top(bottom) surface, the volue of the radial residual stress varies with the plate’s thickness, and the regularities of distribution of the radial residual stress are identical. The volue and the regularities of distribution of the circumferential residual stress vary with the plate’s thickness. At the mid-thickness surface, the volue and the regularities of distribution of radial residual stress vary with the plate’s thickness. The volue of the circumferential residual stress varies with the plate’s thickness, and the regularities of distribution of the radial residual stress are identical.