摘要
根据单向石墨纤维增强铝基复合材料的微观组织特征,构建了包含基体、纤维和界面的代表性体积单胞,建立了考虑基体合金和界面渐进损伤行为的单胞有限元模型,在此基础上分析了复合材料的轴向剪切变形行为。结果表明,由于单胞有限元模型中考虑了界面损伤与破坏行为,数值模拟得到剪切模量和剪切强度均低于细观力学理论公式的预测值。在轴向剪切载荷作用下,复合材料首先发生界面损伤和局部界面失效,轴向剪切变形初期的宏观应力-应变曲线呈现出线弹性特征;此后,相邻纤维之间的基体合金发生局部损伤,随剪切应变的增大,基体损伤逐渐累积并导致基体的局部失效,使得宏观剪切应力-应变曲线呈现非线性特征;剪切变形后期,纤维间隙内基体合金失效区域进一步扩展至界面,从而导致复合材料整体上失去承载能力,界面破坏与基体合金失效是引起复合材料轴向剪切失效的主要机制。在特定的基体合金和纤维力学性能条件下,增加界面结合强度可一定程度上提高复合材料的轴向剪切极限强度和断裂应变。
According to the microstructure characteristics of unidirectional graphite fiber-reinforced aluminum matrix composites, a representative volume element(RVE) containing the matrix, fiber and interface was constructed, and a FE model of element considering the matrix alloy and the progressive damage behavior of interface was established. On this basis, the axial shear deformation behavior of the composites was analyzed. The results show that the shear modulus and shear strength obtained by numerical simulation are lower than those predicted by the empirical formula of micromechanics because the interface damage and failure behavior are considered in the finite element model. Under the axial shear load, interface damage and local failure of composites occur at first, and the macroscopic stress-strain curve at the beginning of axial shear deformation shows a linear elastic characteristic. Thereafter, the local damage occurs in the matrix alloy between adjacent fibers, and the matrix damage gradually accumulates with the increase of shear strain and leads to local failure of the matrix, which makes the macroscopic shear stress-strain curve show non-linear characteristics. In the later stage of shear deformation, the failure area of matrix alloy between the fiber further expands to the interface, which makes the composites eventually lose its bearing capacity. Interface damage and matrix alloy failure are the main mechanisms causing axial shear failure of the composites. Under the specific mechanical properties of matrix alloy and fibers, the axial shear strength and fracture strain of composites can be enhanced by increasing the interface bonding strength to some extent.
作者
刘涛
刘丰华
蔡长春
沈高峰
王振军
徐志锋
余欢
LIU Tao;LIU Feng-hua;CAI Chang-chun;SHEN Gao-feng;WANG Zhen-jun;XU Zhi-feng;YU Huan(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China;AVIC Jiangxi Hongdu Aviation Industry Group Co.,Ltd.,Nanchang 330096,China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2022年第7期171-180,共10页
Journal of Plasticity Engineering
基金
国家自然科学基金资助项目(52165018
51765045)
航空科学基金资助项目(2019ZF056013)
江西省自然科学基金资助项目(20202ACBL204010)
国防基础科研计划项目(JCKY2018401C004)。
关键词
铝基复合材料
细观力学
轴向剪切
渐进损伤
失效机制
aluminum matrix composites
micromechanics
axial shear
progressive damage
failure mechanism
