基于倾角影响线的简支梁桥损伤识别

摘要

In order to promote the application of the influence line theory in structural damage identification,the damage identification indexes based on difference and difference curvature of angular influence line before and after the damage of the simply-supported beam bridges are proposed.The concept of angular influence line of simply-supported beam bridges is defined,the formula of angular influence line before and after the damage of the simply-supported beam bridges is derived,the formula of new damage identification indexes is deduced,and the feasibility of using the new damage identification indexes for damage identification is theoretically proved.To verify the correctness of the new damage identification indexes,the finite element model of simply-supported beam bridge is established.The result shows that the difference of angular influence line before and after the damage of the simply-supported beam bridges has a peak value in damage area;the difference curvature of angular influence line before and after the damage of the simply-supported beam bridges is 0 in the non-damage area,and not 0 in the damage area.The conclusion is that the difference of angular influence line before and after the damage of the simply-supported beam bridges can be used to determine the location of damage with high accuracy.By using the difference curvature of angular influence line,it not only has the good recognition effect to the single damage and multiple damage,but also can realize the recognition of the damage degree of the simply-supported beam bridges.%为了推广影响线理论在结构损伤识别方面的应用,提出了一种基于简支梁桥损伤前后倾角影响线差值及差值曲率的损伤识别方法.对简支梁桥倾角影响线的概念进行定义,推导了简支梁桥损伤前后的倾角影响线公式,并对损伤识别指标进行公式推导,从理论上证明了将其用于损伤识别的可能性.为验证本文建立损伤识别指标的正确性,建立简支梁桥结构有限元模型进行分析.结果表明:简支梁桥损伤前后的倾角影响线差值在损伤区域出现峰值;简支梁桥损伤前后的倾角影响线差值曲率在无损伤区域均为0,在损伤区域均不为0.分析得出结论如下:简支梁桥损伤前后的倾角影响线差值用于判别损伤位置准确度较高;利用简支梁桥损伤前后的倾角影响线差值曲率不仅对单处损伤和多处损伤均具有良好的识别效果,而且可以实现对简支梁桥损伤程度的识别.