A New Crack Propagation Model Based on the Notch Analysis Methodology

基于缺口分析原理的裂纹扩展速率新模型

School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China

Received: 12 February 2017

Abstract

In this paper, the fatigue crack propagation model of the metal structure is studied, and a new crack propagation rate model is proposed. Compared with the traditional method, only the nominal applied stress and the critical fracture stress are considered in the new method, and the new one is much easier and more efficient. By analyzing the 2024-T351 and 7075-T6 aluminum alloy materials test data, the new model is validated and the results are compared with the classical method of crack propagation. The result shows the new model has a similar trend with the existing crack propagation curve, and provides a better description for the low rate and high rate area, it also shows a strongly practicability.

摘要

针对金属结构疲劳裂纹扩展速率的模型进行了相关研究，提出了一种新的裂纹扩展速率模型。该模型在进行裂纹扩展速率分析时，仅需要考虑名义应力及临界断裂应力，相较于传统的应力强度因子分析方法，该方法更加简单有效。通过应用已有材料Al2024-T351及Al7075-T6的试验数据对该方法进行了曲线拟合，并与现有方法所得到的裂纹扩展曲线进行了对比。结果表明新方法与传统方法获得的裂纹扩展曲线走势大致相同，并且对裂纹发生扩展行为的低速率及高速率区域能够提供更好的描述，证明了新模型具有较强的实用性。