纤维增强复合材料机翼长桁压缩破坏预测方法

A Failure Prediction Method of Fiber-Reinforced Composite Wing Stringer Subjected to Compressive Loading

提出了一种分析和预测在压缩载荷作用下纤维增强复合材料机翼长桁的极限承载能力以及破坏位置的方法,建立了分析其形变和渐进破坏的有限元模型,采用应力描述的二维Hashin失效准则预测材料的初始失效,并提出了一种材料受损后的刚度折减方案;由应力失效和断裂力学中的能量释放率控制材料渐进损伤的演化模式,并以损伤变量的形式表征材料的受损程度;在有限元软件ABAQUS/Standard平台上编写用户材料子程序(UMAT),运用黏性正则化方法帮助收敛,并将其预测结果与复合材料机翼长桁的压缩实验结果加以对比.结果表明,所得极限承载能力以及破坏位置的预测结果与相应的实验结果较吻合.

A method for predicting and analyzing the ultimate load and the location of failure of fiber rein- forced composite wing stringer subjected to compressive loading was proposed. A three dimensional FE model was established for displacement and damage analysis. The onset of damage was predicted by 2D Hashin＇s initiation criterion. A new stiffness degradation method of damaged material was suggested. The progression of damage was controlled by a damage evolution law, which combines stress failure and fracture energy dissipation of fracture mechanics. The model characterized damages in the form of damage vari ables was implemented with a user subroutine UMAT of ABAQUS/Standard by using a viscous regu larization method which improves the convergence. The numerical prediction was compared with the exper imental results of the compression test of composite wing stringers, and the ultimate load and failure location correlate well with the prediction results.