基于亥姆霍兹原理的激光焊小孔腔体发声基础理论研究

激光焊接过程中产生的声信号带有大量焊接熔深信息，且具有响应速度快、非接触测量等特点。但由于目前对声源发声现象与机理研究不完善，使它在激光焊接中应用受到限制。. 近期研究发现，激光深熔焊过程中小孔为一狭长腔体，等离子体/金属蒸汽从腔体内喷射出来，该过程可类比亥姆霍兹共振腔发声过程，这为深入研究小孔腔体声源发声提供新的途径。鉴此，本项目率先参考声学中亥姆霍兹模型，结合深熔焊接的特点，对小孔腔体发声机理进行整体探索。. 本项目拟研究声信号与小孔腔体声源发声内在联系，建立有关模型及算法；揭示焊接工艺参数对小孔腔体作用机理，得到不同形状小孔腔体产生声信号基本规律，计算小孔腔体辐射声场和动态声源实时声压，评价焊接过程焊缝质量。该项研究有助于发现和提出新概念，为声信号在激光焊接检测中应用奠定理论基础。

Acoustic signal generated in laser welding processing is a suitable parameter of quality procedure detection, as its advantages of fast response, non-contact measurement and containing a large number of welding penetration information. However, because the research on mechanism of acoustic sources is not a system and there are many unknown phenomenon, its application is restricted in the laser welding.. A recent study found that the keyhole generated in deep penetration has a long and narrow cavity and the plasma/metal vapor spray for the cavity body. This processing can be analogy Helmholtz resonator voice, which provides a new approach for studying the acoustic generation by the keyhole cavity. Therefore, this project is firstly explored the acoustic mechanism of keyhole cavity, combining with the Helmholtz model and deep penetration characteristics.. This project intends to study the inner link between the acoustic signal and keyhole cavity source. Then the models and algorithms can be set up for obtaining the basic rule of different shapes of keyhole cavities generating acoustic signal. After that, the radiation sound field of the keyhole cavity and the real-time dynamic source pressure are all calculated which used to evaluate the quality of welding seam. This research helps find and put forward a new concept for acoustic signal used in laser welding test theory basis.