基于声发射信号特征的高速焊凝固热裂纹在线检测方法研究

项目名称： 基于声发射信号特征的高速焊凝固热裂纹在线检测方法研究

项目编号： No.51475159

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 机械、仪表工业

项目作者： 何宽芳

作者单位： 湖南科技大学

项目金额： 85万元

中文摘要： 凝固热裂纹是高速焊焊接结构危害最大的缺陷之一，现有检测方法无法实现对其快速、准确的在线检测，是制约高速焊接技术实现焊接结构高效化生产的技术瓶颈。项目提出基于声发射信号特征的高速焊凝固热裂纹在线检测方法。首先，研究焊接凝固热裂纹冷却热冲击作用动力学模型，揭示焊接凝固热裂纹冷却过程动态断裂行为及声发射响应机理，探求热裂纹断裂参数与声发射响应特征的映射关系，构建热裂纹热冲击作用下的声发射表征函数；研究焊接凝固热裂纹冷却热冲击作用声发射波动模型，揭示声发射信号时域、频域和时频域特征及其在焊接结构中的传播特性；其次，研究复杂噪声背景下声发射信号微弱特征信息提取方法，构建基于多域、多通道声发射特征信息融合的热裂纹状态敏感特征向量；最后，研究基于声发射特征向量的热裂纹智能识别模型，实现焊接凝固热裂纹状态高精度识别，为实现焊接凝固热裂纹在线、准确的检测提供基础理论和关键技术，具有重要的学术意义和应用价值。

中文关键词： 焊接凝固热裂纹；声发射信号；响应机理；特征提取；在线检测

英文摘要： Welding hot crack is one of the most harmful defects in high-speed welding structure. The existing detection methods are unable to conduct the online detection, so the high speed welding technology is diffcult to realize the purpose of high efficiency production of the welding structure. Therefore, this project proposes the online detection method for welding hot crack based on the characteristics of acoustic emission signal. Firstly, the dynamics model of welding hot crack under transient thermal impact is studied to reveal the dynamic fracture behavior and acoustic emission response mechanism of welding solidification hot crack, the mapping relationship between the hot crack fracture parameters and the response characteristics of acoustic emission signal are obtained, the acoustic emission characteristic functions are established as different crack morphology. The acoustic emission wave model is also studied to reveals the time, frequency and time-frequency domain characteristics of acoustic emission signal as well as the propagation. Secondly, the modern signal analysis methods are studied to propose the multi-domain feature extraction methods of acoustic emission signal, and build the sensitive feature vector of welding hot crack with the information fusing of multi-channel acoustic emission signal. Thirdly, based on advanced pattern recognition method, the high precision detection and identification method for the welding hot crack is proposed by the acoustic emission characteristic vector. The project aims to provide the theoretical foundation and technical support for the accurate online detection of welding hot crack, has important significance of academic and application.

英文关键词： welding solidification hot crack;acoustic emission signal;response mechanism;feature extraction;online dectection