Material and Welding Technology

Acoustic Emission Examination - The Modern Alternative

The acoustic emission examination (AE) is a non-destructive testing and inspection method to locate failures and leakages within pressure equipment. Acoustic emission examination gives an overall view of the physical condition and density of the tested structure.

Detecting and locating possibly existing failures and leakages is effected with the help of a classical physical principle. It is applied for the advantage of industry by means of today's data recording and processing.

Even the blacksmiths of the ancient world realized that metals released audible soundwaves when subject to load, bending, pressure or pulling (e.g. "screaming tin") and avoided the overloading of materials with simple procedures. Sound emissions result from defects in the different materials or leakages in containers. When energy is applied, voltage discharges in the form of sound impulses. The resulting energy is recorded by sensors applied on the surface of the examined unit.

The sound source can be located by means of chronological measurement of the impulses with the help of an algorithm. Therefore AE is an ideal integral inspection method for larger pressure vessels. Due to the results only selected areas must be subjected to the additional conventional non-destructive examination.

One of the most essential advantages of acoustic emission examination is the feasibility to examine pressure equipment and storage tanks with regard to leakages and corrosion "online", i.e. during operation or short standstills. The tank or pipe does not always have to be excluded from the production procedure. In many cases the reliability of information gained by means of AE is higher than the results of normal pressure tests or visual internal examinations.

This versatile testing procedure is state of the art and combines highest possible safety with optimal availability of production factors. TÜV Austria has been appliying the acoustic emission examination since the seventies and has gradually developed and improved this testing method. TÜV Austria plays a leading role in Europe in this field and is your competent partner for efficient resource management.

Dipl.-Ing. Peter Tscheliesnig

Head of the Institute of Technical Physics