激光干涉在蜂窝夹心层板振动模态测量中的应用
Vibration Modal Measurement of Honeycomb Sandwich Panels Based on Laser Interferometry

采用激光电子散斑干涉测量技术(electronic speckle pattern interferometry, 简称ESPI)对悬臂矩形损伤蜂窝夹心复合板稳态振动下的振型进行了实验研究。通过完整试样的振型测量结果与有限元模拟均匀悬臂金属板结构振型的类比，验证了有关蜂窝夹心复合材料具有横观各向同性假设的观点，获得了悬臂矩形蜂窝夹心复合层板前14阶离面振动模态的振型图。实验结果表明，结构的损伤导致其局部刚度改变，使得共振频率减少，损伤对其高阶振型的形状改变较为明显，有时甚至是模态跃迁。
Vibration characteristics of cantilevered honeycomb sandwich panels with local damage are studied by use of electronic speckle pattern interferometry (ESPI). By comparing with the results of finite element modeling simulation on cantilevered aluminum plate, the viewpoint of the homogeneous characteristics of honeycomb sandwich structures can be verified. The first fourteen out-of-plane resonant mode shapes of an intact plate are obtained by experimental method. The experimental results show that comparing with those of intact one, resonant frequencies of the honeycomb sandwich panels will become lower with the structural damage appearance, and the resonant mode shapes also change with the damage location and orientation. Veering in the mode shapes can be observed when the damaged structures vibrate at higher order resonant modes.