Papers by Author: Zhi Feng Jiang

Abstract: A three dimension model of some aircraft engine’s pipeline has been established to study dynamic characteristics of the pipeline under random excitation. The relationship between the supports’ parameters and the dynamic characters of the pipeline was also presented. In order to avoid the harmful resonance, depress the vibration level and reduce the dynamic stresses of the pipeline, a specific dynamical optimized method was proposed and the supports’ layout and parameters (location, quantity) were analyzed and optimized. The results show that 1) Under random excitation, the maximum stresses are located near the bushing with serious stress concentration and the ends of pipeline. Fracture failure easily occurs in these parts. 2) The supports’ optimized method of the pipeline proposed in this paper is reasonable and effective. And the optimized pipeline has less dynamic stress and better anti-vibration capability.

Abstract: The stress distribution of adhesively-bonded single lap joints under tensile shear loading is analyzed using 2-dimensional elastic-plastic finite element method (FEM). Special attentions have been put on the influence of void in adhesive on the stress distribution of adhesively-bonded joints. The results show that the stress concentration of the void is less than that of the end part of the joints when adhesive layer’s deformation was in the range of elastic. Moreover, the influence of the void on the stress distribution becomes less when the void moving from the end-part to the middle. The stress concentration becomes larger and the stress distribution of adhesive’s mid-thickness region becomes flatter when adhesive layer has biggish plastic deformation. Finite element results show an agreement with the theoretical results.

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.