Temperature-dependent modulus of glass fiber/epoxy composite laminates was studied at temperatures ranging from room temperature up to 120℃. The storage modulus, loss modulus, loss factor, and glass transition temperature of two layer-up composite laminates were investigated by dynamic mechanic analysis. Static flexural modulus was also measured by control force mode in dynamic mechanic analysis. A new and simple temperature-dependent model both for the dynamic storage modulus and static flexural modulus was developed. This model depends only on one parameter which has specific physical meaning. The model prediction showed excellent agreement with our own experimental results over the full range of transition region. Furthermore, comparing our model’s prediction and other experimental data of many types of composites, which were studied by other researchers, we point to the fact that our model can be applied to many different polymer matrix composites.

The effects of hydrostatic stress and concentration-dependent elastic modulus on diffusion-induced stress (DIS) in a cylindrical Li-ion battery are studied. It is found that the hydrostatic stress has little effect on the distribution of stresses but the change of elastic modulus has a significant effect on the distribution of stresses. The hydrostatic stress has little effect on the location of maximum hoop stress in active layer. The change of elastic modulus can slow down the trend with closing to the inner surface for the location of the maximum hoop stress in active layer with the thicker current collector or larger modulus of current collector and speed up the trend with closing to the outer surface with the smaller ratio of electrode radius to thickness. The current collector should be as thin and soft as possible when its premise strength is satisfied. The ratio of electrode radius to thickness should be preferably larger than 15.