Betriebsforschungsinstitut Vdeh Institut Fur Angewandte Forschung Gmbh

Betriebsforschungsinstitut Vdeh Institut for Angewandete Forschung Gmbh

Gunther Coen

Dietmar Oberhoff

Roland Keck

Ernst Luhn

Ernst Lunh

Fritz Isselstein

The invention relates to a method for non-destructive testing of materials, in which at least two differently guided waves (modes) are produced in the solid body, each at at least one specified angle, the measured reflection values are placed in relation to a reference echo in order to obtain a relative reflection value, and the relative reflection values of the individual modes are again placed in relation to one another, thereby enabling the size and type of the defects to be determined.

Defect type classifying method

There is disclosed an electromagnetic transducer for the transmission and ception of ultrasonic waves in the touchless testing of metal workpieces, particularly made of steel, in the shape of sheet and strip material. The transducer is arranged for continuous testing, particularly as applied to continuously advancing material, by wavelength spectroscopy and particularly modal spectroscopy of received ultrasonic waves. To this end, the transducer comprises a pair of transducer segments each of which has a set of mutually parallel conductor tracks formed on a substantially planar printed circuit board in which the frequencies and wavelengths for each segment can be preset in a matrix logic circuit having a short time sequence. The conductor tracks comprise windings arranged to be connected for operation through a set of switching elements in such a manner as to produce in various switching states of the switching elements a plurality of wavelengths for each frequency. The wavelengths being proportionally related to each other by small integral numbers.

Electromagnet transducer

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Dusseldorf, Germany

Gunther Coen