联合整体和局部模态信息钢管焊接结构模型修正

由于焊接结点的复杂性、实际测量的局限性以及误差等因素，钢管焊接结构的模型修正一直是研究的热点和难点问题。对一个发射台骨架进行了整体及局部模态试验，获得了反应结构整体动态特性的低阶模态及局部动态特性的局部模态，并将二者联合起来，采用信赖域优化算法进行模型修正。在优化过程中，通过提出的加权系数可动态改变的多目标函数，在每次迭代完成后可根据目标函数数量级的变化自动调整加权系数，使得模型修正过程能够更加合理有效的利用结构的整体及局部模态信息，达到更好 “联合”。修正后有限元模型的计算模态与实测模态吻合良好，验证了本文方法的有效性和优越性。

Model Updating of Steel-tube Welded Structures Using Global and Local Modal Information

For the complexity of welded joints in steel-tube welded structures, the limitation of sensors layout and inevitable measurement errors in testing, the model updating is becoming a difficult problem and a hot research area. To solve the problem, the global and local dynamic tests of the framework of a launching platform are carried out, and the global and local modals are measured. Using these modals, the model updating by means of the trust region optimization algorithm is done. In the process of optimization, by using the proposed multi-objective function with a dynamically variable weighting coefficient, which can be automatically adjusted according to the change of the orders of the objective function in each iterative loop, the measured global and local dynamic information can be used more completely and efficiently. The effectiveness and accuracy of the proposed method are verified by the results of the model updating.