基于桥联模型参数反演的复合材料力学性能预测

PREDICTION OF COMPOSITE MECHANICAL PROPERTIES BASED ON MATERIAL PARAMETERS REVERSELY CALCULATED BY THE BRIDGING MODEL

复合材料的性能参数是结构设计计算的关键。在实际工程中厂商提供的数据资料往往不全,直接影响结构分析设计的精度。因此,本文基于桥联模型提出了在有部分单向复合材料和纤维或基体数据的前提下,反演计算其余关键参数的方法。并进一步将该方法应用于T700/Epoxy单向复合材料偏轴拉伸强度的预测中,与实验结果进行了对比分析。研究表明所研究的方法可以利用有限信息反演计算出结构计算所需要的材料性能数据,在T700/Epoxy单向板的预测中,10°、15°、60°、75°、90°理论与实验误差在10%以内,预测精度较高。本文提出的方法有助于提高复合材料结构的设计效率,减少实验成本。

Mechanical properties of a composite are the key to the simulation of a composite structure.A micromechanical model can predict the mechanical response of a composite from the properties of the fiber and matrix.However,it is frequently encountered that only a part of the mechanical properties of the fiber and the matrix are available in engineering applications,which directly affects the design accuracy of a composite structure.Thus,a reverse calculation process is presented in this work,with which the lacking mechanical parameters can be calculated from limit experimental data of the composite and the fiber and matrix.Firstly,all the available data of the unidirectional composite and the fiber and matrix are collected.Then the undetermined parameters into linear or nonlinear parts are clarified.Finally,the undetermined parameters by the micromechanical bridging model are calculated.The elastic parameters of a composite and the fiber and matrix are enough for the calculation of linear undetermined parameters,while stress-strain curves of a composite must be given for the calculation of nonlinear parameters.In order to validate the reverse calculation process,a series of off-axis tension tests of a T700/Epoxy UD composite are conducted.Only the elastic modulus of the composite,the longitudinal parameters of the fiber and the Young′s modulus of the matrix are available from the material provider.The other elastic parameters of the fiber and the matrix are obtained by the reverse calculation process.Then,the off-axis tensile strengths of the UD composite are predicted based on the bridging model with the reverse calculated parameters.For the cases of 10°,15°,60°,75°,90°off-axis tension,the predicted errors are less than 10%,which is accurate enough in engineering application.Thus,the reverse calculation process is validated.The presented reverse calculation process can increase the design efficiency and reduce the experimental cost in design.