环境变化下基于AR模型系数和协整的海洋平台结构损伤识别

结构损伤引起的损伤特征参数的变化往往被环境因素（温度、质量）变化引起的损伤特征参数的变化所掩盖，从而导致基于振动的损伤识别方法失效。该文利用时间序列中的AR模型系数和计量经济学中的协整进行环境因素（温度、质量）影响下的海洋平台结构损伤识别研究。首先利用AR模型对实测的加速度响应信号进行拟合，选择第一阶AR系数为协整变量，然后对不同节点的协整变量进行协整，将协整残差作为损伤指标，最后通过X-bar控制图进行结构的损伤识别。海洋平台结构的数值模拟和振动台模型试验结果验证了该方法的有效性。

STRUCTURAL DAMAGE IDENTIFICATION BASED ON AR MODEL COEFFICIENTS AND COINTEGRATION FOR OFFSHORE PLATFORM UNDER ENVIRONMENTAL VARIATIONS

Changes of damage feature caused by structural damage are often masked by the changes caused by environmental variations (temperature, mass), resulting in the failure of vibration based damage identification methods. In this paper, the coefficients of AR model in time series and cointegration in econometrics are used to identify the damage of offshore platform in changing environmental variations (temperature, mass). Firstly, the AR model is used to fit the structural acceleration response from different nodes of the offshore platform pre and post damage, and the first-order AR coefficient is selected as cointegration variable. Secondly, the cointegration procedure is applied to the variables from different nodes and the cointegration residuals are taken as the damage indicators. Finally, the X-bar control chart is employed to identify the damage of structure. The results of numerical simulation and shaking table model test of a five-floor steel offshore platform verify the effectiveness of the proposed method.