薄板结构开裂特征声-振响应的实验研究

通过对薄板的振动及近场声场的测量探讨不同开裂特征对薄板结构的振动特性及近场声场响应的影响。首先对具有不同开裂形状、尺寸、位置的薄板结构进行了模态仿真计算,得到理论模态振型。然后通过激光测振仪进行振动实验,实验分析开裂薄板的结构模态,同时布置传声器列阵测量近场声压,通过近场声全息理论重构薄板表面声压分布。最后对比开裂薄板理论模态形状与实验测量结果,分析开裂特征对薄板结构的振动特性及近场声场响应的影响。分析结果表明开裂特征对薄板结构的固有频率和振型有明显影响,同时薄板的声响应跟薄板的振型密切相关。

Experimental Study on Vibro- acoustic Response of Thin Plate with Cracks

The effect of different cracking characteristics on the the vibration characteristics and nearfield sound field response of thin plate is discussed. Firstly,the mode simulation analysis of thin plates which have different shapes,sizes and locations of cracking is calculated,and the theoretic modal shape is given. Then the vibration testing is done by laser vibrometer. The experiment analyzed the modal of cracking thin plate and measured nearfield sound pressure simultaneously by arranging the microphone array. The surface acoustic pressure distributions of the thin plate are reconstructed by means of nearfield acoustic holography（ NAH）. In the end,the modal of cracking thin plate and the experimental results are compared. The effect of cracking characteristics on the the vibration characteristics and nearfield sound field response of thin plate is analyzed. The analysis shows that the effect of cracking characteristics of thin plate on the natural frequencies and vibrational modes is evident,and the vibra- acoustic response of the thin plate is closely related to the vibrational modes of the thin plate.