Residual Strength of Impacted Composites: Analysis and Tests

The influence of impact damage on the structural performance of composite laminates was investigated by a joint effort including nondestructive evaluation (NDE), mechanical testing, and analysis. The impacted NASA-Industry Standard Compression After Impact test specimen was chosen. Damage characterization was based on ultrasonic methods. Computerized ultrasonic inspection from both sides of the test panels provided accurate information on the damage area. From the NDE data a simplified damage model was constructed and analyzed for strength and stability. Failure loads and modes were predicted. Compression after impact tests were performed for various materials and applied impact energies. All test results were in very good agreement with the analytical predictions.