纤维增强钛基复合材料结构强度计算模型建立与修正方法

Establishment and Modification of Structural Strength Calculation Model for Fiber Reinforced Titanium Matrix Composites

关键词:  纤维增强复合材料  宏-细观力学  应力集中系数  结构强度  模型修正  界面开裂

Key words:  Fiber reinforced composites  Macro-meso mechanics  Stress concentration coefficient  Structural strength  Model updating  Interfacial crack

摘要:

为了对SiC纤维增强钛基复合材料结构强度进行准确预测，基于宏－细观力学跨尺度分析方法，对复合材料强度进行计算。建立了复合材料层合板的有限元仿真计算模型，对复合材料层合板在横向拉伸与压缩载荷作用下的损伤演化及失效强度进行预测，并进行试验验证。建立细观力学代表体积元（RVE）模型，对模型施加周期性边界条件，实现横向拉、压载荷下基体的应力集中系数以及失效强度的计算。考虑结构实际受载中，复合材料的界面开裂对横向强度的影响，对模型进行修正，分析界面开裂的过程，计算修正后模型的应力集中系数以及失效强度，修正后的模型预测精度提升6.51%，与试验值误差为24.17%，验证了纤维增强复合材料强度计算方法的有效性。

Abstract:

In order to accurately predict the structural strength of SiC fiber reinforced titanium matrix composites， the strength was calculated based on macro-meso-mechanical cross-scale analysis method. The finite element simulation model of composite laminates was established to predict the damage evolution and failure strength of the composite laminates under transverse tensile and compressive loads， and the experimental verification was carried out. The representative volume element （RVE） model of meso-mechanics was established， and the periodic boundary conditions of the model were realized. The stress concentration coefficient and failure strength of matrix under transverse tensile and compressive loads were calculated. Considering the effect of interface cracking on transverse strength of composite under actual load， the model was modified and the process of interface cracking was analyzed. The stress concentration coefficient and failure strength of the modified model were calculated， and the prediction accuracy of the modified model was improved by 6.51%， and the error was 24.17% compared with the experimental value， which verified the validity of the strength calculation method for fiber reinforced composites.