From discretization to continuous; advanced mechanical measurements using continuous scanning methods

Abstract

Mechanical measurements are commonly performed by discretizing a continuum in a set of acquisition positions at which a transducer can measure a response to a stimulus. Mechanical behaviours of a test piece can be represented and understood by information obtained from these discrete positions. The discretization of a continuum is required because of the measurement methods, which are often developed using transducers at fixed locations both with contact and contact-less types. Measurement systems, such as Scanning Laser Doppler Vibrometer (SLDV) one, are becoming more used in dynamic testing thanks to the ability of measuring vibrations remotely by moving the laser spot anywhere on a test structure. Contactless transducers of this type can measure responses either at fixed positions or by sweeping continuously a test area. The latter measurement technique is called Continuous Scanning. This work is focussed on the advanced modal testing using Continuous Scanning LDV methods, where the modal properties of a test structure can be measured very efficiently and rapidly by using these methods. The continuous scanning is a measurement method which can move away from the discretization of a measurement space thanks to the capability of measuring meaningful parameters. © The Society for Experimental Mechanics, Inc. 2012.