An emerging trend in experimental dynamics: Merging of laser-based three-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 system. The result is a continuous description of the 3-D translational and rotational velocities on the surface of a vibrating prototype structure. This has been demonstrated on 2-D (flat plates) and 3-D structures such as compressor shells. The availability of this basic experimental measurement tool opens the door to many advances in experimental dynamics measurements. This paper will outline the basic approaches used to derive 3-D velocity or mobility response measurements from a vibrating structure. Next, applications of the technology will be discussed. Most important among these is the discussion of the development of a new experimentally based system modelling procedure, where the frequency response at any point and direction may be predicted without having measured that specific combination of forcing and response positions. This new modelling procedure will form the basis for the supplementation of experimental modal analysis as one knows it today. Other uses of this technology such as strain field display, stress field determination, acoustic radiation predictions from the structure, and power flow from sources to sinks in a structure. (C) 1998 Academic Press Limited.