Experimental study on fatigue behaviors of notched composite laminates

The study on the fatigue behaviors of composite laminates is presented in this paper. Both static and fatigue tests are performed to specimens with different notched types. The experimental results showed that the ultimate strength and initial stiffness of various notched composite laminates are almost as same as un-notched ones. The fatigue life of notched specimens is much higher than un-notched ones. Composite materials are notch insensitive compared with metals. The properties measured by using bar type specimens can not represent the real properties of composite laminates. Notches on the free edge may be helpful to the structure. The stiffness change of specimens during fatigue is also studied. The stiffness changes of laminates used in this study can be described as three stages. The fatigue life can be predicted through theoretical models that established by using residual stiffness model.