The Multislope model: A new description for the fatigue strength of glass fibre reinforced plastic

A set of equations is proposed to describe the fatigue behaviour of E-glass laminates under loads with various means and amplitudes. The equations enable a simple method for life time predictions of laminate structures subjected to fatigue loads with continuously varying mean stress. The shape parameters describing the new model will be optimised by minimising the least square sum of the shortest distance. An extensive data set of measurements with constant amplitudes is used to demonstrate the accuracy of the model and clearly shows the fundamental difference in damage accumulation between a mean stress on tension and a mean stress on compression.