Validation of a Lamb wave-based structural health monitoring system for aircraft applications

An effective structural health monitoring methodology for damage isolation based on multisensor arrangements

“…In such cases, pseudo-damages can be used to enable the use of the same structure in a large variety of tests, since they do not cause permanent changes in the properties of the structure, such as stiffness, mass and acoustic impedance. Pfeiffer and Wevers [17] used two iron cubes pressed against each side of an aluminum plate and Kessler and Shim [18] used a rectangular weight to simulate the same effect, as a real damage would have on the propagation of Lamb waves. In this work, a spherical mass of 30 g was used to obtain a punctual mass change on the plate, which may represent damage.…”

Co-located triangulation for damage position identification from a single SHM node

“…Thirty-six visual indicators were drawn at the intersections of the circle and the rays to mark the field of damage locations. A common "inverse damage" technique was used, where stiffness and mass is added to the specimen rather than removed so that representative damage could be introduced in a reversible, repositionable and reproducible fashion [25]. In this case, 3 sizes of small magnets (3.2, 6.4 and 12.7 mm diameter) were placed at the marked positions on the plate using shear couplant gel.…”