网壳结构损伤识别的数值模拟及试验研究

NUMERICAL AND EXPERIMENTAL STUDY ON DAMAGE DETECTION OF RETICULATED SHELL

网壳结构工程事故频繁发生,对其进行损伤识别及健康监测已迫在眉睫。针对网壳结构特点,推导了剩余模态力理论和最小秩摄动理论的基本公式,研究二者在大型网壳结构损伤识别应用中的有效性。依据相似理论,设计制作单层短程线网壳结构模型,对其进行模态试验研究,获取了损伤识别所必需的实测结构模态参数。利用Guyan静态缩聚技术进行有限元模型缩聚,采用最小秩摄动理论进行有限元模型修正,对比研究了基于数值模拟数据和试验实测数据的损伤位置判定及程度评估的整个过程。结果表明,基于剩余模态力和最小秩摄动理论的两阶段损伤识别算法不仅可以识别结构单损伤位置和多损伤位置,还可以定量评估损伤程度,对网壳结构的健康诊断是可行的。

With more and more accidents on the reticulated shells in recent years, damage detection and structural health monitoring on it has become extremely urgent. Based on the characteristics of reticulated shells, the formulations of residual modal force and the minimum rank perturbation theory are derived. The feasibility of the two algorithms to detect the damage in the large-scale reticulated shells is investigated. According to the similarity theory, one single-layer geodesic dome was designed. Modal test on the structural model were carried out and the structural modal parameters for damage detection were obtained. Guyan reduction and the minimum rank perturbation theory were used to reduce and modify the finite element model respectively. The whole damage location and extent evaluation procedure based on the numerical data and experimental data are compared. The results show that the two-step damage detection algorithm based on the residual modal force and the minimum rank perturbation theory can determine the single damage location and the multi-damage location, and can evaluate the damage extent. It is feasible to health diagnosis in reticulated shells.