混合边界子结构的航空发动机机匣模型修正

Model updating of an aero-engine casing based on the mixed boundary substructure

提出了一种基于混合边界模态综合的复杂结构有限元模型修正方法。其主要步骤包括:(1)子结构划分,根据结构形式划分待修正区域,得到子结构和残余结构;(2)缩聚和装配,利用混合边界模态综合法,将子结构内部自由度集缩聚至混合边界自由度集,得到子结构缩聚矩阵,并与残余结构的系统矩阵进行装配;(3)修正,基于灵敏度分析方法,对装配后的残余结构进行参数修正。将该方法应用于航空发动机外机匣的精细化有限元建模及模型修正研究,针对局部连接结构参数修正,子结构模型修正方法的参数收敛后最大误差为0.64%,其计算效率提高了5.15倍。算例结果表明,该方法在保证修正精确度的同时,能提高大规模复杂结构有限元模型修正的计算效率。

A complex structure finite element model updating method based on the mixed boundary component mode synthesis（CMS）was proposed.The major steps of the proposed finite element model updating method include：（1）substructure partition,partition of the updating area into substructure and residual structure according to the junction ways.（2）Reduction and assembly,reduce the internal degree of freedoms（DOFs）to the mixed boundary DOFs by mixed boundary CMS,and assemble the reduction matrix of substructureinto the residual structure physical matrix.（3）Updating,assemble residual structure model updating by sensitivity analysis.The proposed approach was applied to the aero-engine casing refined finite element modeling and model updating.For the local junction parameter updating,the maximal error was 0.64%for the substructure model updating method,and the computational efficiency improved by 5.15 times.These results demonstrate that the method can guarantee the accuracy of the model updating,and improve the numerical computational efficiency of the large-scale complex structure.