考虑基于变分模态分解的冲击载荷截止因数影响的管系响应

Impact Response of Piping Considering Impact Load Cut-off Factor Based on Variational Mode Decomposition Method

针对海上浮式装置力学分析中选用不同截止频率阈值得到重构的冲击载荷对结构响应结果有较大影响的问题,采用变分模态分解(Variable Mode Decomposition,VMD)方法得到冲击载荷各本征模态函数、对应频谱的特征频率和最大加速度幅值。选取不同的截止因数,重构得到不同的冲击载荷。数值仿真结果表明:当截止因数为0.01时,重构的冲击载荷动力学响应与原始冲击载荷动力学响应基本保持一致;在保证足够的安全裕度的前提下,当截止因数选0.20时,可获得更低的截止频率。

In view of the problem that there is significant impact on the structural response results using different cut-off frequency thresholds to obtain reconstructed impact loads in the mechanical analysis of offshore floating devices,the Variational Mode Decomposition(VMD)method is used to obtain the eigenmode functions of the shock load,the primary peak frequency of the corresponding frequency spectrum and the maximum acceleration amplitude.By selecting different cut-off factors,different impact loads are be obtained by reconstruction.The numerical simulation results show that:when the cut-off factor is 0.01,the dynamic response of the reconstructed shock load is basically consistent with that of the original shock load;on the premise of ensuring sufficient safety margin,the lower cut-off frequency can be obtained when the cut-off factor is selected as 0.20.