基于扩展有限元XFEM的TC21钛合金应力强度因子数值模拟分析

Numerical Simulation Analysis of Stress Intensity Factor of TC21 Titanium Alloy Based on Extended Finite Element Method (XFEM)

摘要

TC21钛合金作为一种高强高韧、损伤容限型结构钛合金在国防军工、航空航天领域应用广泛，其在航空航天应用场景中多处于力场、温度场等多场耦合工况下，因此，量化研究其疲劳损伤容限性能具有非常重大的意义。本文针对疲劳裂纹扩展过程中应力强度因子K这一重要指标，分别进行了理论计算和基于XFEM的裂纹扩展数值模拟；通过结果分析证明了该模拟结果和实际情况较为接近，与理论计算结果误差在5%以内，可以准确的反映三维CT试样裂纹扩展过程；同时也验证了裂纹扩展过程“隧道效应”的存在，即内部裂纹的扩展速率往往大于表面裂纹。

Abstract

TC21 titanium alloy, as a high-strength, high-toughness, damage-tolerant structural titanium alloy, is widely used in the defense, military, aerospace fields. In aerospace applications, it is often subjected to multi-field coupling conditions such as force field and temperature field. Therefore, quantitatively studying its fatigue damage tolerance performance is of great significance. This paper focuses on the stress intensity factor K, an important indicator in the fatigue crack growth process, and conducts theoretical calculations and crack growth numerical simulations based on XFEM. The results analysis proves that the simulation results are relatively close to the actual situation, with an error of less than 5% compared to the theoretical calculation results, which can accurately reflect the crack growth process of three-dimensional CT specimens. At the same time, it also verifies the existence of the “tunnel effect” in the crack growth process, that is, the growth rate of internal cracks is often greater than that of surface cracks.

关键词

CT试样 / XFEM / 裂纹扩展 / 应力强度因子K

Key words

CT specimen / XFEM / crack propagation / Stress intensity factor

参考文献

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