大跨度空间格构结构一般具有模态信息不完全等特点,高模态密度,和高自由度。针对这些特点造成的大跨度空间结构损伤检测中的误判问题,提出了一种基于时间序列模型的损伤识别方法。首先,自回归移动平均(ARMA)模型的顺序是根据Akaike信息准则(AIC)选择的。然后,采用长自回归方法对ARMA模型进行参数估计,提取模型自相关部分的残差序列。此外,引入主成分分析(PCA)来降低模型的维数,同时保留特征值。最后,马氏距离(MD)用于构建损伤敏感特征(DSF)。中国太原植物园的圆顶是世界上最大的非三角形木格贝壳之一。依托该结构的结构健康监测(SHM)项目,本文通过数值模拟验证了损伤识别模型的有效性,并通过SHM测量数据确定了穹顶结构的损伤程度。结果表明,所提出的损伤识别方法能够有效地识别大跨度木格结构的损伤,定位损伤位置,并估计损坏程度。构建的DSF对小损伤和环境噪声具有较强的鲁棒性,对SHM在工程中具有实际应用价值。
Large-span spatial lattice structures generally have characteristics such as incomplete modal information, high modal density, and high degrees of freedom. To address the problem of misjudgment in the damage detection of large-span spatial structures caused by these characteristics, this paper proposed a damage identification method based on time series models. Firstly, the order of the autoregressive moving average (ARMA) model was selected based on the Akaike information criterion (AIC). Then, the long autoregressive method was used to estimate the parameters of the ARMA model and extract the residual sequence of the autocorrelation part of the model. Furthermore, principal component analysis (PCA) was introduced to reduce the dimensionality of the model while retaining the characteristic values. Finally, the Mahalanobis distance (MD) was used to construct the damage sensitive feature (DSF). The dome of Taiyuan Botanical Garden in China is one of the largest non-triangular timber lattice shells worldwide. Relying on the structural health monitoring (SHM) project of this structure, this paper verified the effectiveness of the damage identification model through numerical simulation and determined the damage degree of the dome structure through SHM measurement data. The results demonstrated that the proposed damage identification method can effectively identify the damage of large-span timber lattice structures, locate the damage position, and estimate the degree of damage. The constructed DSF had relatively strong robustness to small damage and environmental noise and has practical application value for SHM in engineering.