Ultrasonics

Ultrasound is used both for traditional defect detection and for determination of material properties and the influence of environmental effects. Automatic scanning can be performed in a water tank using pulse-echo or through-transmission techniques. A wide range of materials can be evaluated: Metals, ceramics, fibre reinforced plast and sandwich materials. For the moment the main focus is on testing of fibre reinforced composites. For these materials delaminations are a major concern and ultrasonic testing is the best technique for finding such defects.

A new air-coupled ultrasonic equipment has recently been installed in the department. The advantages of this techniques is that the measurements can be done I air.

Traditional ultrasonic testing requires either direct contact or a liquid as coupling media. The air-coupled technique shall mainly be used for sandwich materials where water intrusion often is a problem.

The department is involved in several projects concerning development of new improved materials where ultrasonic testing is an integrated part of the project. Often the technique is used to characterise the specimens before destructive tests are performed. Ultrasonic testing is a good complementary technique to X-ray.