纤维/聚合物基体界面性能的原位表征

建立了复合材料界面强度原位测试系统,研制出界面剪切强度有限元分析软件并探讨了影响界面剪应力分析的因素,提出了改进的微观力学模型;利用该系统,研究了表面经不同改性处理的CF增强PMR-15聚酰亚胺复合材料界面的微观力学性能,结果表明:有效的表面处理可使CF/PMR-15界面剪切强度明显提高,并与其宏观性能具有较好的对应趋势。本文还初步探讨了界面破坏的过程。

EVALUATTION OF INSITU FIBER/MATRIX INTERFACIAL PROPERTIES

The fiber/matrix interface plays an important role in controlling the mechanical performance of composites.This paper describes a new method for determining the in situ fiber/matrix bond properties of realistic composites.An in situ interfacial strength testing (ISIST) instrument based on the precise position,auto-loading and data acquisition system has been established.In the test,a compressive load is applied axially to the end of individual fibers in a small specimen cut from the real composite,until interfacial microdebonding occurs.The interfacial shear strength of composites can be obtained by using the debonding force through a finite-element analysis.Several factors which affect the analysis of interfacial shear stress are investigated,and a modified micromechanic model of tested fiber,surrounding matrix and surrounding fibers is given.Based on the ISIST technique,this paper investigates the interfacial bond properties between carbon fiber and PMR-15 polyimide matrix for actual composites,and the influences of different treatment methods of carbon fiber surface on the interfacial shear strengh of CF/PMR-15 composites are discussed.Finally,the interfacial debonding mechanism is preliminarily studied combined with TEM technique.