Modal analysis of machine tools using a single laser beam device

Abstract

Two main vibration measurement principles are dominating the modal analysis. These are laser vibrometers used as three-beam scanning devices for open surfaces as in the automotive and aerospace industries and three-axial accelerometers used in cases, where laser vibrometers are not applicable due to difficulties with the line-of-sight, very big sizes of tested structures, particularly high 3D precision requirements or simply due to the high costs. In our paper 'Modal Testing using Tracking-Interferometers' at IMAC XXX we presented a method and a measurement device for simultaneous 3D vibration measurement using a single laser beam. This paper introduces the now fully implemented and partly automated testing method using this technique and device for experimental modal analyses. We describe the vibration measurement as well as geometry measurement the latter used to set-up the animation model for complex structures. We proceed with a detailed planning of the measurement procedure taking the example of our demonstrator machine. Finally we discuss our research on some main limitations and uncertainties of the system particularly the dynamic limitation of reflector mounting. © The Society for Experimental Mechanics, Inc. 2013.