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空间网格结构通常是由相同或相似的子结构按照某种规则在三维空间范围内排列而成,由于组成结构的杆件相似、繁多且密集,致使结构具有较高的超静定次数,且频谱分布十分密集,这给空间结构的模态识别和模型修正带来了挑战。基于实测数据,首先运用ANSYS有限元软件建立精确的数值分析模型用于模型修正,同时通过实测手段采集到环境荷载激励下的结构温度数据和振动数据,继而采用频域分解法(FDD法)、自然激励技术联合特征系统实现算法(NEx T+ERA)识别出结构的模态频率和振型,最后通过混合优化算法修正结构节点刚度、杆件刚度和结构质量等参数来实现对结构有限元模型的修正。修正结果显示:该修正方法可大大缩减有限元模型模态频率与结构真实模态频率间的误差,达到了修正目的。
Space grid structure is usually the same or similar sub-structure according to some rules in the three-dimensional space range from the composition of the structure of the rod is similar, numerous and dense, resulting in a structure with a higher number of statics, and The spectral distribution is very intensive, which poses a challenge to the modal identification and model modification of the space structure. Based on the measured data, the finite element software ANSYS was used to establish the accurate numerical analysis model for model correction. At the same time, the structure temperature and vibration data under environmental load excitation were collected by real measurement. Then the frequency domain decomposition (FDD) Natural excitation technique combined feature system algorithm (NEx T + ERA) to identify the structure of the modal frequencies and modes, and finally by hybrid optimization algorithm to modify the structure of the node stiffness, stiffness and structural quality of the structure parameters to achieve the structural finite element model Correction. The results show that the proposed method can greatly reduce the error between the modal frequency of the finite element model and the true modal frequency of the structure, and achieve the purpose of correction.