Laser scanning vibrometry
The scanning laser vibrometer is a fast imaging method for contactless measurement of vibrations, for example in the automotive, aerospace and mechanical engineering, microsystem and information technology as well as in the quality and production control. The optimization of resonant behavior and acoustics (eg operating vibration analysis ) has become in many of these areas has become an important goal of product development, because the dynamic and acoustic characteristics of products are among the key quality characteristics.
The operating principle is based on the laser Doppler vibrometer: velocity and displacement are determined from the back-scattered from a vibrating structure laser light. In a scanning vibrometer laser Doppler vibrometer with a scanning mirror unit and a video camera is integrated in a measuring head. During the measurement of the laser beam over the surface of the measurement object is scanned, and provides a very high spatial resolution sequentially a series of single point measurements. For these sequentially measured vibration data can be determined and visualize the mode shapes in the relevant frequency bands either in the time domain of the simultaneous movement of the structure, or from the analysis in the frequency domain. In contrast to this, the contact measuring method to be examined, vibration is not affected by the measuring process. The accessible with today's vibrometers measuring ranges cover the entire area of technically relevant vibrations completely. Thus, with the Vibrometry one hand motions of microstructures with swing paths of a few pm at frequencies up to 30 MHz (and thus v = 0.1 m / s) to analyze, but on the other hand also fast processes in Formula 1 engines with swing speeds of up to 30 m / s
A 3D scanning vibrometer combines three sensors that detect the oscillating movement from different directions, and thus completely determine the 3D vector vibration. In the 3D representation of the vibration data allows the vibrations of the measurement object observe spatially or individually in the x-, y -and z- direction, while also in-plane and out- of-plane vector components clearly distinguishable from each other.