Delamination is one of the critical defects in composite materials and structures. Ultrasonic C-scan imaging technique, which maps out the acoustic impedance mismatched area with respect to the sample coordinates, is particularly well suited for detecting and characterizing delaminations in composites. However, to properly interpret the inspection results, it is necessary to correlate the detected indications with the detection limits and probability of detection (POD) of the nondestructive evaluation (NDE) ...
A stiffness-based statistical model is proposed for predicting the fatigue life of composite laminates under constant-amplitude tensile cyclic loadings. The model parameters are determined using measured stiffness degradation data. Experiments were performed on graphite/epoxy pi over 4 laminates to verify the analytical model. It is demonstrated that the correlation between the experimental results and the theoretical predictions for the fatigue life distribution is very reasonable. (Author).
The United States Air Force requires that Air Force aircraft be designed to be durable. This requirement necessitates an analytical demonstration that excessive cracking within the airframe will not occur during the aircraft's design service life. In order to predict the time at which excessive cracking occurs, an analysis is needed which is capable of predicting the distribution of crack sizes within the airframe at any point in time. Such ...
Reports by Author
