A fatigue crack quantification model for metallic structure based on strain monitoring data

基于应变监控数据的金属结构疲劳裂纹量化模型研究

¹ School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China
² Department of Strength Design, AVIC the First Aircraft Institute, Xi'an 710089, China
³ School of Aeronautic Engineering, Air Force Engineering University, Xi'an 710038, China

Received: 14 October 2022

Abstract

Obtaining the real-time fatigue crack length of a metallic structure is the prerequisite of the fatigue life monitoring and residual life estimation for an aircraft. This paper proposed a metallic structure's fatigue crack prediction model using strain monitoring data based on deep learning method. A cycle consistent adversarial network was developed to map the strain monitoring data from experimental measurement with those from finite element modeling. A crack size classification model and a crack length quantification model were proposed to classify the crack size range and identify the exact crack length, respectively. The proposed model was applied to predict the fatigue crack growth in centeral hole metallic plates subjected to random loading spectrum. The results showed that the prediction is effective and accurate.

摘要

实时获取金属结构的疲劳裂纹长度是开展飞机单机寿命监控和剩余寿命估算的基础。采用深度学习方法, 提出了一种基于应变监控数据的金属结构疲劳裂纹长度预测模型, 通过构造循环对抗网络模型、裂纹尺寸的分类模型和裂纹长度的量化模型, 分别实现了含裂纹结构的应变试验数据与有限元模型数据的映射、裂纹尺寸范围的准确分类、裂纹长度的精确量化。将上述方法应用于中心带孔金属板在随机载荷谱下的疲劳裂纹监测, 有效实现了疲劳裂纹长度的实时预测。与试验结果对比表明, 单孔板的孔边疲劳裂纹长度预测误差小于1 mm, 满足工程实际的需求。