基于Nastran等离子喷涂厚壁零件涂层中残余应力分析

基于有限元数值分析对等离子喷涂不同的基体上的喷涂陶瓷涂层和金属涂层中残余应力进行了分析,结果表明:涂层与基体体系的最大应力分布在接触界面附近,由中心线向外依次递增,在边缘处达到最大值。在体系中心区域正应力沿厚度方向逐渐减小,而在涂层中应力分布则趋于线性;建立了涂层中各残余应力分量的准数方程式,准数方程式与数值计算结果显示了较好的吻合,而且对于不同基体-涂层体系均是适用的。无因次最大径向应变、无因次剪应力侵入深度和无因次最大径向应力的大小均取决于涂层厚度与弹性模量的积和基体半径与基体弹性模量积之间比值,而影响无因次径向最大剪应力的大小的根本因素为涂层厚度与光斑半径的比值。

Numerical Simulation of Residual Stress Distributions in Plasma-Sprayed Coating on Thick Wall Component

The residual stress distributions in the plasma sprayed coatings on thick wall component were modeled and numerically simulated in finite element method,based on the software package Nastran.The impacts of the coating conditions,including the species of the coating and substrate,i.e.ceramic or metal,on the residual stress were evaluated.The simulated results show that the strongest stress distribution exists at the coating/substrate interface,increasing in the radial direction and peaking at the edges;and that the normal stress in the central area of the substrate decreases with an increase in substrate depth,and linearly distributes in the coating.Various key factors,including the dimensionless equation of radial stress,shear stress,maximum stain and immersion depth of the residual stress in the coating,were determined.The results,calculated with the dimensionless equation,agree fairly well with the simulated ones in all the coating/substrate systems of interest.The influence of various factors,such as the thickness and elastic modulus of the coating,and the radius and modulus of the substrates,on the variations in the residual stress distributions was also tentatively discussed.