A Numerical Simulation of Time-Dependent Interface Failure Under Shear and Compressive Loads in Single-Fiber Composites

Abstract

We performed a numerical simulation of a time-dependent interfacial failure accompanied by a fiber failure, and examined their evolution under shear and compressive loads in single-fiber composites. The compressive load on the interface consists of Poisson's contraction for matrix resin subjected to longitudinal tensile load. As time progresses, compressive stress at the interface in the fiber radial direction relaxes under the constant longitudinal tensile strain condition for the specimen, directly causing the relaxation of the interface frictional stress. This relaxation facilitates the failure of the interface. In this analysis, a specific criterion for interface failure is applied; apparent interfacial shear strength is enhanced by compressive stress, which is referred as quasiparabolic criterion in the present study. The results of the stress recovery profile around the fiber failure and the interfacial debonding length as a function of time simulated by the finite element analysis employing the criterion are very similar to experimental results obtained using micro-Raman spectroscopy.

Prediction of long-term durability of unidirectional CFRP

“…In the second section, the experimental results of time and temperature dependence of matrix and composite strengths are shown. In the third section, the SFF model is introduced and recently presented interfacial failure criterion is described, [5][6][7][8][9][10] and then estimated and experimentally obtained composite strengths are compared. In the fourth section the validity and application of the results are discussed, and then a method for predicting the long-term durability of CFRP is proposed.…”

Temperature dependence of glass fiber/epoxy interface normal strength examined by a cruciform specimen method

“…It should be noted that the temperature-independent interfacial strength is obtained for the ''normal'' strength [10] and the temperature-dependent interfacial strength is obtained for the ''shear'' strength [11]. Since obtaining precise interfacial ''shear'' strength is very complicated [2,3,12], the temperature dependence of interfacial strength should be proven by the same examination as in the present study, if possible under wide range of test temperature conditions including lowtemperature. At the low-temperature condition, the microscopic observation is very difficult.…”

“…In order to justify the assumption, the composite strength at elevated temperature is equivalent to the long-term strength, the temperature dependence of interface strength is desired to be understood at least. In fact, very few studies deal with the time and/or temperature dependence of the interface strength [9][10][11][12][13]. An interesting aspect is that Ref.…”

Micromechanics analysis of carbon fiber/epoxy microdroplet composite under UV light irradiation by micro‐Raman spectroscopy

“…The energy of the ultraviolet radiation is sufficient to induce bond dissociation between the polymer matrix and the bonds formed between the resin and the carbon fibers by the coupling agent during the curing of the composite, which is consistent with the obtained FTIR results (Figure ). Another possible reason for the occurrence of this phenomenon might be the residual stress introduced by thermal contraction …”