Fatigue/Impact Studies in Laminated Composites
Final rept. 10 Sep 1980-31 Dec 1982
NORTH CAROLINA AGRICULTURAL AND TECHNICAL STATE UNIV GREENSBORO DEPT OF MECHANICAL ENGINEERING
Pagination or Media Count:
The residual strength of the impact-damaged laminates can be predicted using an analytical model. Both the power law and the wearout models appear to be useful in predicting the fatigue life of the composite laminates. However, because of the slope parameter, the wearout model appears to have a slight edge over the power law model, particularly at low fatigue life and higher applied stress. The strength degradation due to cyclic loading in notched laminates was found to be extremely small up to a million cycles. The residual strength of the fatigue-damaged laminates was found to increase in proportion to the applied maximum stress with R 0.1 after a million fatigue cycles. Impact loading followed by cyclic loading was found to be more damaging in reducing the life of the laminate than the reversed sequence of loading. The magnitude of the minimum projectile velocity causing catastrophic failure in the laminates tested was found as a function of the applied stress and the number of fatigue cycles.
- Laminates and Composite Materials