基于Guyan缩聚与均布载荷面曲率的柱壳损伤识别

Damage Identification of Rocket Skin Based on Guyan Polycondensation and Uniform Load Surface Curvature

针对工程中采用模态测试对火箭柱壳结构的蒙皮进行损伤识别时,存在高阶模态较难获取和实际结构测点自由度与模型自由度不匹配的问题,提出基于Guyan缩聚与均布载荷面曲率的损伤识别方法。通过对柱壳蒙皮有限元模型的2次Guyan缩聚,将其平动和转动自由度缩聚到法向上,并以法向的模态振型作为输入参数,构建基于均布载荷面曲率的损伤指标,数值分析了该指标对火箭柱壳蒙皮的损伤识别效果。结果表明:缩聚后的模型能够完全满足工程需求;所提方法只需低阶模态参数,不但可以识别出柱壳结构单损伤和多损伤位置,而且能够给出损伤程度的相对大小。该方法对工程实际中火箭蒙皮的损伤识别具有重要的参考价值。

In order to solve the problems of damage identification of rocket skin by modal test in engineering,that is difficult to obtain the higher order modes,and the degree of freedom of the actual structure measurement points do not match the degree of freedom of the model.A damage identification method based on Guyan poly⁃condensation and uniformly distributed load surface curvature is proposed.The translational and rotational de⁃grees of freedom are condensed to the normal upward by two Guyan polycondensation of the cylindrical shell skin model.Then the modal shape of the normal direction is taken as the input parameter,and the damage identi⁃fication index is constructed based on the curvature of uniform load surface.The damage identification effect of this index on the rocket shell skin has been analyzed numerically.The results show that the polycondensation model can fully meet the engineering requirements,and the method can be used to identify not only the single damage location but also the multi-damage location,which can also give the relative damage degree.This have great practice application value to the damage identification of rocket skin in engineering.