基于局部脉冲响应的约束子结构修正法

ISOLATED SUBSTRUCTURE MODEL UPDATING METHOD BASED ON LOCAL IMPULSE RESPONSE

该文针对局部子结构为修正对象的情况,提出只利用整体结构中局部子结构部分的脉冲响应即可以精确修正子结构模型的约束子结构方法。它是利用子结构位置的脉冲响应,计算需要施加在结构边界的支座反力,构造出约束子结构的脉冲响应,然后由特征系统实现法(ERA)方法识别出构造响应的模态,进而修正子结构。约束子结构是指在子结构边界施加虚拟支座后的独立结构,它含有单元少而更有利于模型修正。通过修正约束子结构的单元刚度,间接修正整体结构中的子结构,不但可剔除整体结构其他部分的误差对子结构模型修正的影响,提高修正精度,而且可提高计算效率。该文以十跨桁架模型为例,分别利用子结构位置的位移脉冲、速度脉冲和加速度脉冲构造约束子结构并修正子结构,验证了方法的有效性,并分析了噪声对方法的影响。

A substructure isolation method is proposed to update a local substructure by utilizing the impulse response at the corresponding substructural location of the whole structure, which is significant when only a local part of the structure is interested. Firstly support pressures needed to apply on the substructural boundary are estimated via impulse response at the location of a substructure, in order to construct the impulse response of an Isolated Substructure. Then Eigensystem Realization Algorithm （ERA） is used to identify the modal parameters of the constructed impulse response, thereby the local substructure is updated through the model identification and model updating of an isolated Substructure, an individual structure by applying numerical support on the substructural boundary. It contains fewer elements and can be updated easier with high computational efficiency, as well as improved computational precision since that the influence from the other parts of structure is eliminated. A numerical example of a plane truss is given and validates that a substructure could be updated successfully by using the displacement, velocity and acceleration impulse response at the substructural location respectively even with 10% Gauss noise.