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桥梁结构在运营过程中受到外界环境、车辆荷载与自然灾害的影响,不可避免地出现材料性能退化与结构损伤,及时、有效地识别桥梁结构既有损伤,对保障桥梁运营安全具有重要意义。针对现有损伤识别方法准确性低、计算繁琐等不足,以简支梁为研究对象,提出了简支梁两阶段损伤识别方法。首先,采用模态分析提取简支梁前三阶竖向振动模态频率与振型,构建均匀荷载面曲率差进行损伤定位;其次,以典型损伤状态下的均匀荷载面曲率差作为损伤等级中心,计算测试工况均匀荷载面曲率差到损伤等级中心的隶属度,利用模糊隶属度判定测试工况的损伤等级。简支梁数值模型损伤识别结果表明,提出的两阶段损伤识别方法能够有效识别简支梁损伤,具有较高的准确性。
In the process of operation, the bridge structure is affected by external environment, vehicle load and natural disasters. It is inevitable that material degradation and structural damage will occur. It is of great significance to identify the existing damage of the bridge structure in time and effectively, which is very important for the security of the bridge operation. Aiming at the shortcomings of the existing methods of damage identification, such as low accuracy and complicated calculation, a simple two-stage damage identification method for simply supported beam is proposed. Firstly, modal analysis was used to extract the vertical vibration modal frequencies and modes of the first three steps of simple supported beams, and the difference in curvature of the uniform load surface was constructed for damage localization. Secondly, the difference of the curvature of uniform load surface under typical damage was taken as the center of damage grade , Calculating the degree of uniformity of curvature of uniform loading surface under test conditions to the degree of damage grade center, and using fuzzy membership degree to determine the damage grade of test conditions. The damage identification results of the simply supported beam numerical model show that the proposed two-stage damage identification method can effectively identify the damage of simply supported beams with high accuracy.