基于应变指标和D-S证据理论的简支梁桥损伤识别

Damage identification in simply supported beam bridge based on strain index and D-S evidence theory

为了提高桥梁结构的损伤识别准确率,并摆脱对桥梁损伤前信息的依赖,提出基于应变指标和D-S证据理论(Dempster提出由Shafer完善形成的一种推理理论)的损伤识别方法。首先采用结构损伤状态下的动态应变响应分别构建应变标准差(SSD)指标和平均伪比能(APSED)指标;然后利用曲线拟合技术对两个应变指标进行改进;最后根据D-S证据理论融合两个改进的指标来定位损伤。将所提方法用于一个简支梁桥的数值模型,讨论了损伤程度和测试噪声对损伤识别结果的影响,发现SSD和APSED对噪声具有较强的鲁棒性,且损伤识别结果准确率高,并通过实验研究验证了所提方法的有效性。

In order to improve the accuracy of bridge structure damage identification, and get rid of the dependency on the information before damage, a damage identification method based on strain index and D-S evidence theory is proposed. Firstly, the dynamic strain response of damaged structure is used to construct the strain standard deviation (SSD) index and the average pseudo strain energy density (APSED) index. Secondly, both of the two strain indexes are modified by the curve fitting technique. Finally, based on the D-S evidence theory, two improved indexes are fused to locate the damage. The method is applied to the damage identification of a simply supported beam bridge with numerical model, and the effects of damage degree and test noise are discussed. The results show that SSD and APSED have strong robustness to the noise, and high accuracy of damage identification can be achieved. The effectiveness of the proposed method is eventually verified by the experimental investigation.