CHARACTERIZATION AND EVALUATION OF NON-DESTRUCTIVE TESTING USING ULTRASONIC LAMB WAVES
dr. Justina Šeštokė St. Ignatius of Loyola College
Keywords: Lamb waves; elastic properties; composite materials.
Abstract:
Composite materials are widely used in modern technologies. Their applications are very diverse – from everyday products to high-tech applications. Composite materials created using various innovative materials (mica, carbon structures, nanostructures, glass, etc.). This is a heterogeneous material and has a complex material structure. The application of ultrasonic guided Lamb waves allows for better detection and characterization of various materials and the existing structure. Ultrasonic guided waves allow for the detection and characterization of not only surface micro-damages of composite structures, but also various types of defects (delamination’s, cracks, thickness variations) inside the structure. The excitation of higher-order ultrasonic guided Lamb waves modes faces many problems, especially when using the air-bonding technique, and has not been sufficiently studied. This is relevant for paper, high-density polyethylene (HDPE), membranes, GFRP, GLARE, CFRP and other composite structures. The aim of the work is to study the excitation and reception of guided Lamb wave modes in high-density polyethylene and composite materials. To aim of this paper, it is appropriate to apply existing and develop new contact ultrasonic measurement methods based on the excitation and reception of guided waves. The obtained results clearly demonstrated the possibility of effectively exciting and receiving different guided Lamb wave modes with very different phase velocities. Comparison of experimental results with simulation results showed good agreement.