Elastic Identification of Composite Materials from Vibration Test Data of Thin and Thick Plates

In many applications, composite materials are preferred to monolithics because of significant advantages such as higher specific strength and specific stiffness, better resistance to fatigue and impact damages and to corrosion, as well as greater liberty for multifunctional design whereby the design serves many purposes at once. These advantages account for the widespread use of composites in the marine, aerospace and consumer goods areas. Established standards by various testing organizations for elastic identification of materials are destructive and are relatively costly and time-consuming. Besides this, in modern industry, net and near-net production methods are becoming more necessary as increasing effort is made to avoid waste. This has made nondestructive testing methods to gain more importance. Vibration test methods are among the simplest and most indicative available. This paper describes the basic approach of this strategy, and recent further work in the use of vibration test data to predict elastic constants of these materials.