变增量扫频法求解结构随机风振响应

WIND-INDUCED STOCHASTIC BUFFETING RESPONSES OF BRIDGES BASED ON A VARYING FREQUENCY-INCREMENT SWEEPING METHOD

结构耦合抖振响应有限元分析的完全二次组合(CQC)频域方法在数值积分过程中,一般都采用等增量扫频。大型结构的实际频响函数一般只有在共振频率附近才有较大的数值,而在其他远离共振频率点的区域频响函数值都很小。基于此,该文提出结构抖振响应变增量扫频的频域分析法。采用基于完全二次组合的CQC法编制结构抖振响应变增量扫频计算程序,该程序在做数值积分的时候采用变增量扫频的方式,在结构共振频率点附近自动加密计算点,而在其他的频率区则间采用较大的增量步长。以某大桥为例,对等增量扫频法和变增量扫频法得到的结果进行比较,证实了变增量扫频法在保证求解精度的前提下能大大的缩短求解的时间,提高效率。

The fixed frequency increment sweeping method is usually employed in buffeting response analysis when using the complete quadratic combination(CQC) finite element method.Generally,the actual frequency response functions of large structures possess a relatively large value when the frequency is adjacent to a resonant value.Based on this fact,a varying frequency-increment sweeping method is proposed in this study.The CQC method is employed in the buffeting response program.A varying frequency-increment strategy is used in the program in regard to numerical integration.Within the range of resonance frequencies the number of integral points increases automatically while larger frequency increments are employed in ranges far away from resonant points.Both the fixed and the varying frequency-increment sweeping methods have been employed in the analysis of buffeting response for one bridge.The results indicate that the varying frequency-increment sweeping method is less time-consuming and numerically more efficient than its fixed counterpart for the same accuracy requirements.