多梁式桥梁检测的叠加曲率模态差变化率方法

鉴于应用曲率模态的桥梁损伤识别研究大多以一维单梁式结构为研究对象,提出利用G-M法的思想并基于薄板振动理论将多梁式结构转化为正交异性板后,类比梁弯曲理论得到该结构两正交方向曲率表达式,通过分析采用单阶曲率模态差指标进行桥梁损伤识别的不足,考虑利用多阶曲率模态变化率叠加指标进行损伤识别,最后采用有限元软件Ansys建立桥梁模型计算单位置、多位置不同损伤程度的多种工况。Matlab绘图结果表明:沿桥梁纵向叠加指标识别更为精确,对未损伤位置数据扰动更小,指标独立性高,可利用该指标进行多梁式结构的损伤定位。

Method of mode difference change rate of superposition curvature for multi-beam bridge detection

Most of the present studies on bridge damage identification using curvature modes only take one-dimensional single-beam structure as the research object. In this paper the idea of G-M method is put forward and the wide multi-beam structure is transformed into orthotropic plate based on thin plate vibration theory. The curvature expressions of the two orthotropic directions of the structure are obtained by analogy beam bending theory. In consideration of the deficiencies of the damage identification of the bridge by using single-order curvature mode difference index, two-direction multi-order curvature mode change rate superposition index for damage identification is used instead, and finally the finite element software Ansys is adopted to establish a bridge model to calculate the unit location, multi-location and different degree of damage under various working conditions. Matlab plotting results show that the index along the bridge longitudinal superposition is more accurate with less disturbance to the data of undamaged location and more index independence, and it can be used to locate the damage of wide multi-beam structure.