Member residual stress field prediction method based on limited test points

Abstract

The invention discloses a member residual stress field prediction method based on limited test points. The method comprises the following steps: 1, carrying out structural discretization; 2, classifying unit nodes, establishing a displacement shape function matrix and a unit stress function matrix, and then solving a unit matrix; 3, according to the unit matrix, establishing a stress shape particle residual stress vector array and an integral node load array, and solving an integral matrix; 4, according to the rank of the integral matrix, determining the number, distribution and testing of experiment test points; 5, according to a tested residual stress experiment result as a residual stress boundary condition, solving all stress shape particle residual stress; and 6, according to the stress shape particle residual stress and the unit stress function matrix, solving non-stress shape particle residual stress so as to obtain a residual stress field of a member. According to the invention, the residual stress of the member can be accurately predicted without restrictions of the material and the structural shape of the member, and the method has obvious advantages especially in a manufacturing process of an unknown member and residual stress prediction of a complex member.

Description

technical field [0001] The invention belongs to the technical field of nondestructive testing, and more specifically relates to a method for predicting component residual stress fields based on limited test points. Background technique [0002] When an object is not subjected to external force, the internal stress system that maintains self-equilibrium is usually called residual stress. Various machining processes, such as cutting, casting, heat treatment, welding, assembly, etc., will produce residual stress to varying degrees, and residual stress has an impact on the static mechanical properties, stress corrosion performance, fatigue resistance, dimensional stability and service life of materials. How to accurately predict the internal residual stress field distribution of components is of great significance to the material and structural design of components, and has become the focus of general attention in recent years. [0003] At present, methods for obtaining compone...

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Problems solved by technology

The finite element simulation method is another method to know the distribution of the residual stress field of the component, but most of the current research is to simulate the distribution from the actual manufacturing process of the component, such as casting, cutting, welding, etc. The stress has changed accordingly, and the residual stress field cannot be characterized only by simulating the casting process. At the same time, due to the lack of a correct characterization method for the initial stress field of the blank, the error between the predicted result and the actual result is large. At the same time, for the component manufacturing process The residual stress prediction of components with complex or unknown manufacturing process is difficult to realize by simulation

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