Strength and Life Prediction of the Composites using MMF and ATM

Abstract

A life prediction procedure of continuous fiber reinforced composites subjected to creep and fatigue loading combining the MMF and the ATM is described in this chapter. The micromechanics of failure (MMF), which is originally to predict the static strength of composites as described through chapters 1-3, is now extended to cover the long-term behavior due to creep and cyclic fatigue loadings. As a first step, the MMF is employed to compute the strengths of the constituents (matrix and fiber) from the ply strengths as a function of temperature. Then, matrix and fiber creep and fatigue master curves are generated using time-temperature superposition principle (TTSP) and shift factors obtained from the matrix compliance tests. A life prediction procedure of composites using the constituent master curves is then described and applied to drawing failure envelopes for general laminates. Creep and fatigue master curves are generated for TR30S/epoxy. Also an attempt is made to generate a standard master curve for the matrix with typical parameters, which will help reduce greatly the number of tests.