Ultrasonic Detection of In-Plane Properties of Composite Laminates

In aerospace applications, composite materials are generally used as load bearing structures. It is the role of nondestructive evaluation (NDE) to provide input concerning deviations in material properties (such as flaws) to structural analysis models so that structural performance predictions can be made. Since composite analytical models require material mechanical properties as input. NDE can best serve analysis by providing quantitative measurements o t these properties. Because most composite structures are designed to carry in-plane loads, NDE should ideally provide information about in-plane mechanical properties such as strengths and stiffnesses. This paper discusses the importance of quantitative NDE and also describes work that is directed at the development of ultrasonic BDE techniques which are sensitive to in-plane elastic properties of composite laminates.