Guided Waves in Filament Wound Composite Tubes
Filament wound composite pressure vessels are being increasingly used in industry. This has resulted in a critical neeed for reliable and effective nondestructive testing methods for quality assurance and safety assessment. This study presents an analysis of guided wave propagation in laminated composite tubes by using finite element method based on Hamilton's principle. Each lamina of the composite tube is assumed to be transversely isotropic medium with five independent material stiffness components. The phase velocities were determined by numerical computation and compared with measurements. The transient guided waves were excited by a Q-switched Nd;YAG laser and were detected by a broadband conical transducer mounted on the surface of a composite tube. After transformation from local coordinates of eaxh lamina to the global coordinates of the tube, the number of independent material constants is still the same for the ones manufactured with symmetric filament winding at ±a angles .Three of the material constants are directly measured by pulse-echoes of pressure wave and shear wave and shear waves propagating along the thickness of the tube. The remaining two stiffness components are determined by inversion of simplex based on phase velocities of the guided waves.
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