Virtual Experimental Modal Analysis (VEMA)

摘要

Experimental modal analysis (EMA) is an accepted methodology for identifying modal parameters of complex system assemblies, but large channel counts and multiple references are usually required to perform a thorough modal survey of such structures. In these cases, modal testing can become very costly and time consuming. Moreover, success in accurately defining all the modes of interest from experimental data depends on a variety of factors, including how and where the excitation is applied, how and where measurement data is acquired, and how boundary conditions or other environmental conditions are simulated. This paper presents a methodology for virtual experimental modal analysis (VEMA), that is, for simulating a complete EMA in the computer, including the test structure, instrumentation, data acquisition and modal parameter identification. This is done by linking two existing commercially available software packages together, one for simulating the instrumentation, excitation, and response of the test structure, and one for post-processing multi-channel test data. This approach greatly improves the chances for a successful test by allowing one to easily perform a large number of virtual EMA's before entering the lab, and thereby determine optimal locations and ranges for instrumentation and excitation.