基于小波变换的冲击载荷定位研究

Study on Impact Locating Based on a Wavelet Transformation Approach

在动载荷识别过程中引入小波变换研究了弹性波在固体内传播的散射特性,提出了利用实测响应的小波变换确定冲击载荷位置的方法。系统实测响应的小波变换峰值对应于散射波的到达时刻,入射波比反射波贡献明显而其最大峰值则对应着入射波的到达时刻,从而可以取得载荷激励与多个响应测量之间的时滞,进而通过散射波群速度与时滞间的关系确定动态载荷的作用位置。计算结果表明,该算法有效地将冲击载荷的定位研究化为一非线性优化问题,避免非线性方程求解上的困难。

As a part of the force identification proce-dures, an approach to impact load locating was presentedby use of the measured responses, based on the fact thatthe wavelet transformation is introduced to study the dis-perse properties for the elastic wave propagation insolids. The peaks of wavelet transformation to the mea-sured system responses are correspondent to arrivingtime of the disperse waves, the contribution to thewavelet transformation magnitude induced by incidentwaves is more than that of reflected ones, and the crestvalue implies time of the disperse wave arriving. Conse-quently, impact locations could be determined from therelations of group velocities and time --delay, since thetime --delays between excitation and responses were ob-tained. The results show that the mentioned methodtransforms impact locating problem into a nonlinear opti-mization, and the difficulties for solving nonlinear equa-tions are avoided.