基于小波包样本熵的连续梁桥损伤识别
Damage Identification for Continuous Girder Bridge Based on Wavelet Packet Sample Entropy

为了减少现行桥梁检测中所需布置传感器数量，将小波包分解和样本熵有机结合起来，对利用单点动力响应数据检测识别连续梁桥结构损伤的新方法进行了研究，笔者提出了连续梁桥结构的损伤识别指标和方法。利用小波包变换对移动荷载作用下桥梁的加速度响应进行分解和重构，计算重构信号的样本熵值，建立了对数加速度能量差小波包样本熵损伤识别指标；并通过三跨变截面连续梁桥的动力仿真分析，验证了指标和方法的适用性与噪声鲁棒性。研究结果表明，笔者所提出指标和方法仅利用桥上一个测点的加速度响应就能够很好地识别连续梁桥的损伤位置和损伤程度，且对噪声不敏感。
In order to reduce the number of sensors arranged in current bridge detection, the wavelet packet decomposition and sample entropy are combined. A novel method detecting and identifying the structural damages of continuous girder bridge by dynamic response signal of single point has been discussed and studied. A novel damage identification index and method of continuous girder bridge has been proposed. In applications, the wavelet packet transform is used to decompose and reconstruct the acceleration response signal of bridge under moving load. The sample entropy values of reconstructed signal have been calculated. Moreover, the sample entropy of wavelet packet transform with different logarithmic acceleration energy has been established to act as a damage identification index. Its applicability and correctness are verified by a three-span continuous girder bridge with variable cross sections. Noise robustness of index is alsoanalyzed. The research results show that the index and method proposed in this paper can identify the damage location and extent by analyzing the acceleration response signals of any points on bridge, which is not sensitive to the noise.