中文摘要：

提出一种基于逐步回归分析的有限元模型修正方法，根据显著性分析，逐步将显著性高的展开项引入，同时剔除不显著的展开项，保证各展开项都是显著的，然后用回归得到的响应面模型代替初始有限元模型进行迭代修正，达到有限元模型修正的目的。采用该方法对一既有铁路钢桁桥的有限元模型进行修正，并与基于灵敏度的模型修正方法进行比较。修正后有限元模型的频率计算值与实测值吻合，修正后的有限元模型能更准确地反映实际结构的力学性能。该方法可以大幅度减少展开式中的待定系数，具有较高的计算精度和效率。

英文摘要：

The finite element model updating method based on stepwise regression is presented.The insignificant expansion terms are eliminated efficiently according to the contribution of expansion terms to the response by the stepwise regression analysis.Then,the constructed response surface models are used to replace the initial finite element model.This approach is applied to update the finite element model of an existing railway steel truss bridge finite element model based on the in -situ dynamic measurement results,and is compare with model up-dating method based on sensitivity analysis.The results show that the updated finite element model can accurate-ly represent the mechanical properties of the bridge and the proposed method can reduce the probabilistic colloca-tion points and unknown coefficients of polynomial expansion significantly on the condition of ensuring calculation accuracy.