非均匀温度场下声发射源定位方法

针对非均匀温度场下声发射信号传播速度不一致导致时差定位法定位精度下降的问题，研究基于波束形成法的声发射源定位效果．首先，基于板波理论研究声发射信号的传播特性，分析频散现象等对声发射信号速度测试的影响；然后通过数值仿真研究声发射波束形成法定位精度对不同重建速度的定位效果，进而发现在声发射波束形成法在阵列方向具有速度不敏感性．在加热前后的薄钢板上进行断铅定位实验，其结果表明声发射波束形成法可以在非均匀温度场中保持较高的定位精度，在机匣温度不均的航空发动机碰摩定位领域有良好的应用前景．

Location method of acoustic emission source in non-uniform temperature field

In view of the location accuracy decrease of time division of arriving (TDOA) method in non-uniform temperature field,the location performance of acoustic emission beam-forming was studied.Firstly,the propagation characteristics of acoustic emission signals were obtained by using plate wave theory,and the main factors affecting the accuracy like dispersion phenomenon are analyzed on the basis of the results.Then,the location performance of acoustic emission beam-forming based on uniform linear array wss explored by numerical simulation,and show that the positioning accuracy on sensors array direction is stable in certain speed range.The artificial acoustic emission sources which were created by breaking a mechanical pencil lead on the plate surface before and after heating were implemented to verify the simulation.The results were analyzed and show that the acoustic emission beam-forming method has high location accuracy in non-uniform temperature field and good prospect of application for positioning stator-rotor rub of aero-engine in which stator has uneven temperature.