DETAILED MODELING AND ANALYSIS OF SINGLE-FIBER MICRODROPLET TEST USING COHESIVE ZONE APPROACH

摘要

The properties of the fiber-matrix interphase in composites have a significant influence on theirrnstructural performance. The microdroplet test method is generally used to characterize therninterphase shear strength between the fiber and the matrix. A methodology is developed tornsimulate and assess the importance of various factors affecting failure mechanisms in thernmicrodroplet test. These factors include the effects of processing-induced residual thermalrnstresses, progressive debonding, unstable crack propagation and frictional sliding. Cohesive zonernmodeling approach within the framework of finite element modeling is employed to simulate therncrack propagation and interphase failure. Qualitative comparisons of the numerical results arernmade with the experimental data for an E-Glass fiber epoxy system. The cohesive zonernparameters critical energy release rate and peak traction are derived from the simulations basedrnon the experimental results for this system. The developed modeling framework allows gaining arnbetter understanding of the fiber-resin load transfer and energy absorption mechanisms of therninterphase. The commercial finite element code LS-DYNA? is used in this work.