Ritz-POD法及其在大跨度屋盖结构风振分析中的应用

目的提出在频域内分析大跨度屋盖结构风致动力响应的新方法——Ritz—POD法，克服传统Ritz向量叠加法的不足，完善Ritz向量叠加法在大跨度屋盖结构风振响应分析中的应用问题．方法将Ritz向量叠加法和本征正交分解法（POD）相结合，用POD得到脉动风压的前几阶本征模态及相应的荷载中心频率，生成考虑多荷载空间分布模式及荷载频率影响的Ritz向量．结果利用Ritz—POD法分析一单层球面网壳的风振响应表明，仅用前5阶本征模态就能较好地描述脉动风压的空间分布形式（约为70％～80％），合理确定外荷载空间分布模式的重要性要比考虑外荷载频率影响更为显著．结论用Ritz—POD法能够合理给出脉动风荷载的空间分布模式，并有效考虑外荷载频率对结构动力响应的影响，可用少量阶数的Ritz向量即可得到较准确的风振响应，显著提高了计算效率，并且该方法包含了结构的主要贡献模态．

A New Load-Dependent Ritz Vector Method for Wind-induced Response Analysis of Large Span Roofs:Ritz-POD Method

A new load-dependent Ritz vector method is presented for wind-induced response analysis of large span roofs which is denoted as the Ritz-POD method.Compared with standard Ritz vector superposition method,the Ritz-POD method is based on the proper orthogonal decomposition(POD)technique,which can take into account the contribution of multiple loading spatial distribution and centering frequencies.With this method,the wind-induced response of a single layer reticular shell is analyzed,which shows that Ritz-POD method can achieve more accurate results with fewer Ritz vectors.The significant contribution modes to wind response with high frequencies are included.So the Ritz-POD method can further improve the performance of the method and apply the Ritz vector superposition method to wind-induced response analysis of large span roofs.