ABSTRACT

This chapter presents the damage detection approach based on the anomalous incident wave energy map using laser ultrasonic technique. It focuses on measuring some characteristic parameters of Lamb waves in composites during the fatigue process with the introduced laser ultrasonic techniques and correlating these parameters to fatigue damages. The chapter explores the laser ultrasonic technique for non destructive evaluation (NDE). It provides the laser-generation-based method as a new way for nondestructive damage accumulation evaluation for composites. Ultrasonic techniques commonly using ultrasound propagation, reflection, and transmission characteristics are directly related to the properties of materials, and thus are widely utilized for NDE of structure damages. Generally, the key point of NDE for fatigue damages in composites is to find a specific parameter that is sensitive to the damage accumulation during the fatigue process. The basic idea of the ultrasonic propagation visualization is to scan one of the excitation and sensing points and fixed the other.