考虑模型偏差的结构动力学模型修正

针对结构有限元模型修正后仍可能存在模型偏差的问题,提出用待修正参数的不确定性来表征模型偏差的有限元模型修正方法。首先,基于响应面方法识别得到待修正参数的最优值,并通过计算结果与试验结果比较获得模型偏差;然后,基于响应面模型并结合灵敏度分析计算得到模型偏差对待修正参数的影响,从而得到考虑模型偏差后待修正参数的区间;最后,通过一个悬臂梁工程实例的模型修正,验证了笔者所提出方法的可行性。结果表明,考虑模型偏差的修正可以提高模型可靠性。

Updating of Structural Dynamics Model with Model Bias

It is necessary to study the finite element (FE) modeling and updating in consideration of the model bias, because there are some model biases to affect the response prediction in the updated engineering structure. The FE model updating method with model bias is proposed, the model bias is quantified by the uncertainties of updating parameters in the method. Firstly, the optimization values of updating parameters are identified based on the response surface model and the model bias is obtained by comparing the simulation results and the test results. Secondly, the effect of model bias on updating parameters is identified by combining the response model and the sensitivity analysis, and then the updating parameters interval is obtained with model bias. Lastly, the proposed method has been validated by model updating on a cantilever beam. The updating results have proved the feasibility of the method. The results show that it can improve the reliability of the structural response predictions when the model biases are considered.