摘要
研究了界面性能对随机短云杉纤维增强聚丙烯(PP)复合材料宏观拉伸性能的影响。采用双线性内聚力模型(CZM)描述随机短云杉纤维和PP基体间非理想界面的力学行为,建立了含非理想界面的随机短纤维增强复合材料代表性单元(RVE)的二维有限元模型,考虑了纤维含量、长细比、随机分布和随机各向异性弹性以及PP基体弹塑性的影响;模拟了不同纤维含量复合材料的实验拉伸应力应变曲线。结果表明,短云杉纤维/PP基体间非理想界面刚度与复合材料有效弹性模量之间有单调递增的曲线关系,即E-K曲线;同一复合材料不同纤维含量的E-K曲线簇有一个临界交点。在交点右侧强界面刚度区复合材料有效模量随着纤维含量的增加而提高,在交点左侧弱界面刚度区有效模量随着纤维含量的增加而减少。三种不同体积含量10%、20%和49%的云杉/PP复合材料的非理想界面刚度可用E-K曲线和实验测得的宏观有效弹性模量确定,云杉/PP界面初始破坏位移和界面完全破坏位移也可根据模拟拉伸应力应变曲线确定。数值分析结果能用非理想界面刚度来解释和理解随机短植物纤维体积含量对复合材料宏观有效模量的影响。
The influence of interface performance on the macroscopic tensile properties for the random short spruce fibers reinforced polypropylene（PP） composite materials was investigated. The mechanical behavior of the imperfect interface between spruce fiber and PP matrix is described by the bilinear cohesive zone model（CZM）, while a two-dimensional finite element model of the representative volume element（RVE） with CZM for the material was developed in terms of the volume content, aspect ratio（AR） and random anisotropic elastic of random distribution short spruce fiber, as well as the influence of elastic plastic PP matrix. Experimental tensile stress strain curves for the composites with different fiber volume contents were simulated. The results show that there exists a common trend of monotone increasing for the curves of imperfect interfacial stiffness versus the effective modulus, namely E-K curves.The E-K curves for the composites with different volume fraction of fibers converged to a unique critical point（CP）. In the range of higher interface stiffness the effective modulus of composites increase with the increase of fiber volume content, in the range of lower interface stiffness that is the opposite. For three spruce/PP composites with different fiber contents of 10%, 20% and 49%（in volume fraction）, their imperfect interfacial stiffness could be estimated by their E-K curves and the measured macroscopic effective elastic modulus through experiment. The displacement corresponding to the initial separation and that tothe entire separation of the interface could also be determined by the simulating tensile experimental stress strain curve of spruce/PP. Therefore, the results of numerical analysis base on the imperfect interfacial stiffness can be used to explain and further understand the influence of random short fiber volume content on the effective modulus of spruce/PP composites.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2016年第9期681-689,共9页
Chinese Journal of Materials Research
基金
国家自然科学基金10972155
11572218和81670884资助项目~~
关键词
短植物纤维
拉伸性能
有限元
纤维/基体界面
有效弹性模量
内聚力模型
plant short fiber
tensile behavior
finite element analysis
fiber/matrix interface
effective modulus
cohesive zone model
