基于多边界切割插值的改进子模型分析方法

Improved sub-model analysis based on cut-boundary of multiple interpolation

应用传统子模型技术进行结构的有限元分析,可以提高计算精度,得到局部的精确解,但仅适用于切割边界为体单元和壳单元的模型,当有其他类型单元通过切割边界时将产生很大的误差。本文对传统子模型技术及存在的问题进行了系统分析,提出了多边界插值方法和改进多边界插值方法,并应用于深水张力腿平台的整体模型和子模型分析,探讨了传统边界插值方法、多边界插值方法和改进多边界插值方法的计算精度。计算结果表明,相比传统边界插值方法,多边界插值方法具有更高的计算精度,随着内外切割边界距离的增大,误差逐渐减小并趋于稳定;改进多边界插值方法能进一步提高内外切割边界距离较小时的计算精度,可以满足梁单元通过切割边界的情况,拓宽了子模型技术的应用范围。

Traditional sub-model technique using for finite element analysis of structures can improve the calculation accuracy and get the exact solutions of local model.However,the technique is only applicable to the model of the body element and shell element in cut-boundary.The significant errors will be caused when other types elements in the cut-boundary.In this paper,traditional sub-model technique and the existing problems were analyzed in detail.The multiple interpolation method and improved multiple interpolation method were proposed and applied to the analysis on the global model and sub model of deepwater tension leg platform.The calculation accuracy of traditional interpolation method,multiple interpolation method and improved multiple interpolation method were investigated.The result show that,compared with the traditional interpolation method,multiple interpolation method has higher calcu-lation accuracy;the error decreases and tends to be stable with the increase of internal and external cut-boundary distance.Improved multiple interpolation method can be satisfied with the condition of the beam element in the cut-boundary and improve the calculation accuracy when the internal and external cut-boundary distance is small,which broaden the application of sub-model technique.