Coupling simulation and experiment in noise and vibration engineering

Computer simulation and experimental testing play major roles in noise and vibration engineering. Modal analysis of structures, for instance, is regularly performed experimentally and with finite element analysis. Often the integration of simulations and experiments consists of nothing more than adjusting a fudge factor, like a material property, to get simulations to agree with test results. However, the current emphasis in industry and research laboratories is to more tightly couple testing and simulation-using test results to validate simulation models and simulation results to design experiments. For example, finite element analysis is used to identify how best to support and excite a structure to produce a particular vibration, and modal test results are used to establish "modal assurance criteria" on finite element simulations. This paper presents two laboratory exercises that demonstrate the importance of coupling computer simulations with experiments for mutual validation. The exercises from a new course in "Acoustics, Noise and Vibration" at GMI Engineering & Management Institute also introduce students to tools and practices used extensively in noise and vibration engineering. The other six experiments in the course, like most undergraduate laboratory experiments, focus on demonstrating physical principles. These two exercises focus on the tools and methods employed in noise and vibration engineering. The first exercise comes near the beginning of the course and deals with the frequency domain analysis of signals using fast Fourier transforms (FFTs). The second exercise, near the-end of the course, deals with structural modal analysis.