摘要
首先利用复合材料纤维断裂单胞模型,编制蠕变损伤子程序,对单胞模型进行蠕变损伤分析。分析了纤维/基体弹性模量比对蠕变变形、蠕变损伤以及应力场的影响。从计算结果发现,蠕变损伤首先在纤维断裂尖端起始,然后沿着一定的角度向基体外围延伸,直至完全损伤,而且纤维/基体模量比对高温环境下的复合材料蠕变损伤产生很大的影响;纤维与基体的模量相差越大,复合材料越容易变形,抵抗蠕变变形的能力就越小,蠕变损伤越严重。经过对不同韧性的基体材料进行研究,发现基体韧性低的复合材料蠕变损伤明显高于高韧性基体复合材料,表明低韧性基体复合材料抵抗蠕变破坏的能力较低。
A unit cell model was applied to study the creep damage behavior after fiber fractures in the fiber reinforced composites at high temperature. The user subroutine CREEP has been programmed for ABAQUS. The fiber breakage results in a new crack. The results show that the stress concentration factor resulted from the fiber breakage increases with the creep time. The creep damage takes place near the crack, and then grows in the matrix along a certain angle, up to the total failure. The influences of the ratio of modulus of the fiber to the matrix ( E f/E m ) on the creep deformation, the damage and stress distributions have been studied. With the increasing E f/E m , the damage in the matrix increases. Analysis on the different ductility of matrix shows that the creep damage of low ductile matrix composites is higher than high ductile matrix composites.
出处
《力学季刊》
CSCD
北大核心
2004年第4期523-527,共5页
Chinese Quarterly of Mechanics
基金
国家自然科学基金(50375124)
陕西省自然科学基金和航空基金
关键词
复合材料
蠕变
损伤
单胞模型
有限元
composites
creep
damage
unit cell
finite element method
