基于内积向量的复合材料结构损伤检测

DAMAGE DETECTION OF COMPOSITE STRUCTURES BASED ON INNER PRODUCT VECTOR

提出了内积向量(Inner Product Vector,IPV)的概念,证明了在白噪声激励下内积向量是由结构各阶模态振型叠加而成,且每阶模态的加权因子仅与结构的模态参数有关,并在此基础上提出了应用内积向量进行结构损伤检测的方法。该方法仅仅利用在白噪声激励下测试的结构振动响应信号,避免了结构有限元建模误差和结构固有模态识别误差对损伤检测结果的影响。通过对复合材料层合梁和层合板的分层损伤检测算例,验证了该方法检测损伤的有效性及准确性。

Inner product vector （IPV） is proposed to characterize the cross correlation of the measured vibration responses of the structure. Then a new damage detection method is put forward based on this concept. It is theoretically proved that the elements in the IPV of a structure is the inner product of the time domain vibration responses of corresponding measuring points, and this vector can be directly calculated by using the measured time domain vibration responses. Under white noise excitation, the IPV of a structure is the superpostion of the vibration modes of the structure, and the contribution of each mode shape only depends on the modal parameters of the structure. Therefore the IPV involves health information of a structure and the difference of the IPVs between the intact and damaged structure can be used as the damage index. The damage location is identified by the abrupt change of IPV curve of the structure. Numerical simulation of the delamination damage detection for a composite laminated beam and plate demonstrate the feasibility and effectiveness of the proposed method.