考虑不确定性的结构损伤概率分析

PROBABILITY ANALYSIS OF STRUCTURE DAMAGE IDENTIFICATION INCLUDING SYSTEM UNCERTAINTY

由于混凝土材料的离散性、测量噪声等因素的存在,在进行损伤识别的过程中需考虑不确定性因素的影响。该文着重研究考虑结构参数不确定下的损伤识别,该文考虑了不确定量为给定均值和方差的正态高斯分布随机变量,基于参考有限元模型和观测的位移响应,利用统计矩的方法,经过两步模型修正,分别得到了无损结构和有损结构的概率模型,进而通过定义的PDE(The probability of damage existence)确定结构各离散单元的损伤存在概率。以白噪声作用下的悬臂梁及非平稳KT谱作用下的十层剪切框架为例,验证该方法的可行性。

Because of many factors such as the discreteness of concrete materials and measured noise, the effects of uncertain parameters should be taken into consideration during the damage identification. This paper proposes a probability approach for the damage identification of structures considering uncertainties in structural parameters. The random parameter is assumed to follow Gaussian and non-Gaussian distribution. Based on the theoretical model and the statistical moment-sensitivity, the probabilistic structural models in undamaged and damaged states are obtained by two-stage model updating, and then the Probabilities of Damage Existence （PDE） of each element are calculated as the damage criterion and two-stage model updating. On the other hand, some improvement has been made to lessen the measured responses with segmentation time. The new stochastic damage detection method can not only locate structural damage but also identify damage severity. A ten-story shear building model subjected to ground motions and a simply supported beam with white noise are considered to demonstrate the proposed method.