AN EMERGING TREND IN EXPERIMENTAL DYNAMICS - MERGING OF LASER-BASED 3-DIMENSIONAL STRUCTURAL IMAGING AND MODAL-ANALYSIS

This paper describes the advances toward the implementation of a three -dimensional, six-degree-of-freedom structural dynamics measurement sy stem. The result is a continuous description of the 3-D translational and rotational velocities on the surface of a vibrating prototype stru cture. This has been demonstrated on 2-D (flat plates) and 3-D structu res such as compressor shells. The availability of this basic experime ntal measurement tool opens the door to many advances in experimental dynamics measurements. This paper will outline the basic approaches us ed to derive 3-D velocity or mobility response measurements from a vib rating structure. Next, applications of the technology will be discuss ed. Most important among these is the discussion of the development of a new experimentally based system modelling procedure, where the freq uency response at any point and direction may be predicted without hav ing measured that specific combination of forcing and response positio ns. This new modelling procedure will form the basis for the supplemen tation of experimental modal analysis as one knows it today. Other use s of this technology such as strain field display, stress field determ ination, acoustic radiation predictions from the structure, and power flow from sources to sinks in a structure. (C) 1998 Academic Press Lim ited.