Residual stress introduced CT sample stress field and crack propagation analysis method

Abstract

The invention relates to a residual stress introduced CT sample stress field and crack propagation analysis method, which comprises the following steps of: establishing a CT sample finite element model by adopting ABAQUS finite element analysis software, and endowing a CT sample with initial stress by a direct assignment method and a file input numerical method; and calculating a stress intensityfactor of the CT sample and carrying out finite element simulation analysis on crack propagation by applying a cloud picture integration and expansion finite element technology. According to the method, the influence of different stress conditions on the crack propagation trend is fully considered, the finite element model for precisely calculating the high-temperature alloy CT sample crack tip stress intensity factor with introduced residual stress and predicting the crack propagation law is obtained, and the influence of stress on the crack propagation trend is effectively predicted; the simulation method can be widely applied to the field of aerospace, and a new thought is provided for research on prediction of residual stress and pretreatment on crack propagation behaviors.

Description

technical field [0001] The invention belongs to the numerical simulation method of fracture mechanics, and relates to the research on the stress intensity factor and expansion behavior of crack tips of superalloys for aerospace under different stresses. Specifically, it is a method for simulating the stress intensity factor and crack propagation of superalloy CT specimen crack tip with residual stress introduced. Background technique [0002] As an important material for aeroengine turbines, blisks and combustion chambers, superalloys have excellent durability and fatigue properties. The failure forms of superalloys are mainly fatigue fracture, stress corrosion, and oxidation cracking, that is, fracture failure under different conditions. Therefore, it is particularly important to study the crack propagation behavior of superalloys. The crack propagation behavior belongs to a very important aspect in the field of fracture mechanics. Fracture mechanics belongs to the field o...

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Problems solved by technology

Failure is the biggest problem that materials need to face in the application process, so many scholars focus on the crack initiation and propagation behavior of materials, but in the research of numerical simulation, how to deal with residual stress is still a big problem

Zhu Yongmei et al. from the School of Mechanical Engineering, Jiangsu University of Science and Technology (Zhu Yongmei, Yao Xiang, Yang Linfeng, Wang Fang, Zhang Jian. Research on the influence of stress intensity factors on the surface cracks of deep-sea spherical shells[J]. Ship Mechanics, 2020,24(03):371- 379.) Established the calculation model of the surface crack stress intensity factor of the spherical shell in the deep sea. On the basis of the known joint stress distribution law, the linearly distributed stress was established through the Analytical Field of ABAQUS, and applied to the weld toe position, and finally successfully applied FRANC3D The software calculates the stress intensity factor of the crack at the weld toe. This method can calculate the stress intensity factor more accurately when the stress distribution law is known and the law is relatively simple, but when the residual stress is unknown or the distribution law is not obvious does not apply when

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