Vibration analysis system collects spatial information

Combined research effort between two Fraunhofer-Institutes is pioneering a new technique to examine vibration patterns in three dimensions. The approach depends on holographic interferometry, applied instantaneously from three different directions, and subsequent number-crunching to analyse the three sets of fringe information. This means that the principal direction of any particular displacement can be discovered, and related to the structure being studied. It may be, for example, that although a frontal vibration pattern can be readily analysed by many different techniques, the actual principal vibration is in a sideways direction, revealing what is really happening. Although the work is largely targeted at analysing vibration patterns in vehicle or machine tool applications, clearly the technique can be applied to any vibration analysis where holography can sensibly be applied. Unwanted vibration of components is often to blame for excessive noise in cars, or machine tools failing to achieve the required processing accuracy. The aim of the research group formed by the Fraunhofer-Insitutes for Laser Technology and Production Technology in Aachen and the Machine Tools Laboratory of the RWTH Aachen is to track down these vibrations. The effects of unwanted vibrations on vehicle or machine components are for the most part obvious. They lead to noise emission and excessive material stress or detract from the precision of printing and machine tools. Engineers have the task of analysing and localising the vibrations in order to provide solutions. They must know which parts vibrate and by how much. This information allows them to make specific constructional alterations or to optimise operating conditions.