Ultrasonic inspection of adhesive joints using flexible linear arrays

Bruch, Tobias; GE Sensing and Inspection Technologies GmbH; Germany

Bruch, T.; GE Sensing & Inspection Technologies GmbH; Germany

ID: ECNDT-0409-2018
Download: PDF
Session: Transportation, railway & automotive UT 2
Room: R2
Date: 2018-06-13
Time: 11:10 - 11:30

Within the last years adhesive joining technologies have become more and more important as a joining technique in different industries. This is driven by the increasing use of multi material combinations as a trend of lightweight construction, where conventional joining technologies cannot be applied. In addition, the adhesive adds to the overall structural strength of the components. These adhesive joints must be tested to meet the high-quality requirements.
The inspection of such adhesive joints is done destructively. Such destructive tests produce scrap cost and they cannot be performed close to the process, thus a timely feedback to the production lines is not possible. To provide a non-destructive quality control of adhesive joints, which can be directly applied at all stages in the manufacturing line, a novel NDT solution for testing adhesive joints has been developed. Due to the geometry of the inspection part which can have complex contours, a new flexible linear array probe design has been developed. These probes can adapt to convex or concave curved contours to follow the contour of the inspection part and cover an area in electronic scanning direction of up to 32 mm. To assess the quality of the adhesive joint, it is crucial to scan and record the full C-Scan of the adhesive joint. Quality criteria for adhesive joints are for example the minimal width of the adhesive, the percental presence of the adhesive over the inspection area or the detection of adhesive voids and canals. Such quality criteria can be directly deduced from the inspection system.
Extensive trials and verification tests on hemming joints in the automotive industry have been carried out to prove the functionality of the inspection system. Further developments for inspecting structural adhesives in car bodies as well as applications in the aerospace sector will be discussed.