Propagation and Attenuation of Elastic Guided Waves in Laminate Fiber-Reinforced Composite Plates

摘要

Elastic guided wave phenomenon in modern fiber-reinforced laminates is a complex mechanical process. Along with the amplitude and dispersion directivity of source-induced wave fields conditioned by the microscopic material anisotropy, the effects originating from the microstructure of fibrous composites play a non-neglectable role. Among such features are the wave attenuation due to the polymer matrix viscosity and the continuous mode conversion phenomenon originating from the severe difference between matrix/fiber mechanical properties. Possessing remarkable intensity, these features should be accounted for in ultrasonic non-destructive testing and structural health monitoring systems for the reliable operation. In this work, we investigate their influence on guided wave propagation in unidirectional laminates experimentally and numerically. In the computational model, viscosity driven attenuation is addressed through the complex stiffness matrix, and semi-analytical integral approach is employed for parametric analysis of source-induced guided wave dispersion properties and transient propagation. To handle the continuous mode conversion effect, the concept of spatially varying material properties and the finite element method are used. Experimental measurements are performed for piezoelectrically excited guided waves with scanning laser Doppler vibrometry technique.