摘要
研究了硅酸铝短纤维增强AZ91D镁基复合材料蠕变力学行为的细观机理,采用单胞模型结合有限元软件ABAQUS进行分析.有限元分析表明,纤维和基体中的应力应变大致为分段均匀分布,纤维远比基体承担的等效Mises应力大,基体和纤维的界面处存在较大的应力集中.复合材料的蠕变断裂经历3个微观进程,随着蠕变变形的增大,短纤维通过多处损伤、断裂和多重断裂来承担和传递载荷而加强了基体的蠕变抗力,弱界面产生的微裂纹不断扩大导致复合材料抗蠕变能力急剧下降而断裂.
A research was conducted on the micro mechanism of the creep mechanical behavior of aluminum silicate short fiber-reinforced AZ91D magnesium matrix composite. The unit cell model was applied together with the finite element method( FEM) of ABAQ US to simulate the composite. The FEM results showthat the distribution of stress and strain in the fiber and matrix is roughly uniform in each segment,the fiber assumes far higher equivalent M ises stress than the matrix,and there is distinct stress concentration around the interface between the matrix and the fiber. The creep fracture of the composite goes through three microscopic processes. With the increase of creep deformation,the short fiber bears and transfers the load with various damages,fracture and multiple fracture,which strengthens the creep resistance of the matrix. The micro-cracks generated at the weak interface continue to expand,causing sharp fall of the creep resistance and in turn fracture of the composite.
出处
《应用数学和力学》
CSCD
北大核心
2014年第5期523-532,共10页
Applied Mathematics and Mechanics
基金
广东省自然科学基金(10151170003000002)
关键词
镁基复合材料
单胞模型
有限元
蠕变断裂
轴应力
magnesium matrix composite
unit cell model
finite element method
creep fracture
axial stress
