Effects of the short‐fiber tip geometry and interphase properties on the interfacial debonding behavior of rubber matrix composites

An axisymmetric finite element model of a single fiber embedded in a rubber matrix was established. A cohesive zone model was used for the fiber–matrix interface because of the interfacial failure. The effect of the fiber tip shape on the interfacial debonding of short‐fiber‐reinforced rubber matrix sealing composites (SFRCs) was investigated; the shapes were flat, semi‐elliptical, hemispherical, and conoid, respectively. The initial strain of the interfacial debonding (ε₀) was obtained. We found that among the researched fiber tips, ε₀ of the SFRC reinforced with the hemispherical tip fiber appeared to be the maximum. The initial locations of interfacial debonding were also determined. The results show that the initial locations of the interfacial debonding moved from the edge to the center of the fiber tip when the ratio of the semimajor axis and semiminor axis of the semi‐elliptical fiber tip increased gradually. Further study on the effect of the interphase properties on ε₀ with the hemispherical fiber tip was conducted. The results indicate that an interphase thickness of 0.2 μm and an interphase elastic modulus of about 752 MPa were optimal for restraining the initiation of the interfacial debonding. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42774.