The Role of Viscoelasticity on the Fatigue of Angle-ply Polymer Matrix Composites at High and Room Temperatures- A Micromechanical Approach

Abstract

A micromechanical approach is adopted to study the role of viscoelasticity on the fatigue behavior of polymer matrix composites. In particular, the study examines the interaction of fatigue and creep in angle ply carbon/epoxy at 25 and 114°C. The matrix phase is modeled as a vicoelastic material using Schapery's single integral constitutive equation. Taking viscoelsticity into account allows the study of creep strain evolution during the fatigue loading. The fatigue failure criterion is expressed in terms of the fatigue failure functions of the constituent materials. The micromechanical model is also used to calculate these fatigue failure functions from the knowledge of the S-N diagrams of the composite material in longitudinal, transverse and shear loadings thus eliminating the need for any further experimentation. Unlike the previous works, the present study can distinguish between the strain evolution due to fatigue and creep. The results can clearly show the contribution made by the effect of viscoelasticity to the total strain evolution during the fatigue life of the specimen. Although the effect of viscoelsticity is found to increase with temperature, its contribution to strain development during fatigue is compromised by the shorter life of the specimen when compared to lower temperatures.

A multiscale approach for fatigue life prediction of polymer matrix composite laminates

“…35 The model was later extended to include the nonlinear viscoelastic properties in closed form functions 36 and to study the effect of viscoelastity on the fatigue behavior of unidirectional polymer matrix composites. 37 Assumption of the SUCM model As mentioned earlier, in the SUCM model, it is assumed that the composite material can be represented by rectangular cross section fiber and matrix subcells. Figure 2 shows the corresponding RVE of the composite lamina.…”

Simulation of interface damage in metal matrix composites under off-axis loading using cohesive zone model

“…2a. a three dimensional cubic RVE is selected with one layer of elements in fiber direction since Table 1 Thermo-mechanical properties of the fiber, matrix and coating [9,19].…”

“…The Simplified unit cell method (SUCM) has been presented to obtain the closed-form solution for overall off-axis behavior of polymer matrix composites [19]. Sun et al have predicted the off-axis behavior of SiC/Ti MMC using an analytical model at room [20,21] and higher temperatures [21].…”

Modelling the effect of temperature on the probabilistic stress–life fatigue diagram of glass fibre–polymer composites loaded in tension along the fibre direction

“…A goal of the current work is thus to provide such relationships. However, because of the temperature-sensitive creep–fatigue interactions present in off-axis composites 4,23,30 – which are not accounted for in the current modelling approach – the analysis is limited to tensile fatigue along the materials main fibre orientation. Therefore, equation (2) simplifies to …”