2.5维C/SiC复合材料板弹性参数识别方法研究

Elastic parameter identification of a 2. 5D C /SiC composite plate

以大型商业有限元软件NASTRAN为计算平台,提出了基于模态试验结果的2.5维C/SiC复合材料板弹性参数识别方法。基于复合材料板的模态试验结果,采用模型修正的思想构造优化问题,其中目标函数定义为实测模态频率与计算频率之差的平方和,将以刚度平均法获得的复合材料弹性参数的理论预测值作为优化问题的初值,充分利用了材料参数的先验信息,然后对材料参数进行灵敏度分析,通过迭代求解识别出复合材料板的弹性参数。识别后,C/SiC复合材料板第1-4阶模态频率的复现精度明显提高,并能保证第5-8阶模态频率的预示精度。研究结果表明,方法能准确识别2.5维编织C/SiC复合材料的弹性参数,并为复合材料等效建模以及进一步动态特性研究提供参考。

By using the large commercial finite element software NASTRAN,a method for elastic parameters identification of a 2.5D C/SiC composite plate based on modal test data was proposed here.An optimization problem was formulated with the model updating technique,its objective function was defined as the sum of squares of the discrepancies between measured and calculated modal frequencies,the initial values of the elastic parameters were obtained by adopting the stiffness averaging method making full use of the prior information of the material parameters.Finally,the accurate elastic parameters of the composite plate were identified through a iteration process by using the sensitivity analysis method.The accuracy of the first 1-4 modal frequencies of the C/SiC composite plate was significantly improved after identification,and the predictive accuracy of the 5-8 modal frequencies could also be guaranteed.Results showed that the proposed method can accurately identify the elastic parameters of the 2.5D C/SiC composite plate,and it can provide an effective reference for dynamic design and equivalently modeling of composite materials.