Abstract

Adhesive joints have numerous applications in many branches of industry, such as civil engineering, automotive, aerospace and shipbuilding. As with most structural elements, adhesive joints can experience any damage mechanism, which induces the need for diagnostic testing. Ultrasonic waves are widely used for non-destructive inspection of many structures and their elements, including adhesive joints. Guided wave propagation method consists in excitation of wave in one point of analysed element and collection of signals in a set of points spread over this element. Further signal processing, such as calculation of root mean square values (RMS), can provide a precise damage imaging, because of a high vulnerability of wave characteristics to any discontinuity. The work is focused on identification and localisation of damaged areas in adhesive film of steelclad concrete beams. Steel-concrete composite elements, such as steel-clad concrete beams containing adhesive joints are commonly used in civil infrastructure. In the conducted research, composite specimens were prepared with the use of an epoxy-based adhesive Sikadur® 30 Normal. Artificial defects were performed by omitting adhesive film on a part of a joint. The input wave signal was provided by the arbitrary function generator. Elastic waves were excited by plate piezoelectric actuator placed on a steel plate. Signals of propagating waves were collected point by point on the surface of steel part of the joint, by means of the scanning laser vibrometer. The maps representing RMS values calculated individually for each signal proved to be an effective visualisation of the actual shape and position of damage areas.

Authors (3)