Effect of Relaxation Moduli on Predictions of Creep Curves for FRP Laminates with Transverse Cracking

Abstract

Numerical simulation is conducted to investigate effect of relaxation moduli of constitutive laminae on creep curves for cross-ply FRP (Fiber Reinforced Plastic) laminates containing initial transverse cracking. The onedimensional viscoelastic shear lag model is employed to predict the strain response to constant applied stress as a function of time. The effect of the time-dependent shear lag parameter on creep curves is also discussed. The strain is calculated numerically with the aid of inverse Laplace transform technique. Two types of relaxation moduli, namely, an exponential type and a power law type, are applied to the model to predict the creep strain for various transverse crack density. It is found that the creep strain increment can be enhanced by relaxation of transverse and shear moduli especially for high transverse crack density.