Role of Electrodynamic Shaker System in Simulating Vibrational Environments

The basic philosophies of simulating vibrational environments are examined in the light of practical electrodynamic shaker systems. Two basically different approaches to simulation are discussed, both of which assume that a component attached to a structure is the subject for test. A distinction is made between the field measurements used as a basis for simulation which represent the responses of particular structures to an environment and the actual environmental forces. The first approach to simulation replaces the structure on which the component is mounted by a shaker. The motion of the shaker is then controlled in such a manner as to reproduce in a statistical sense the response of the structure to the actual environment. A second approach replaces the environmental forces which excite the structure and component by a shaker. The force output of the shaker is then controlled to reproduce the response of the structure to the actual environment. The two approaches are compared pointing out the relative advantages and disadvantages between the two with emphasis on the shaker system requirements.