Shaker Capability Estimation Through Experimental Dynamic Substructuring

Electrodynamic shaker systems are a staple in shock and vibration environments testing, yet the specific performance limits of these systems are not well characterized. Manufacturer ratings give a general idea of a system’s capability, but the details of their performance remain uncharacterized, often leaving test engineers using their best judgment to determine if a test is feasible. This work applies dynamic substructuring to better predict shaker capability throughout the system’s full range. By modeling a shaker system, insight is gained into the potential performance, but the difficulty remains that the dynamics of the system will change depending on how the test configuration is defined. If no analytical model of the article exists, it is challenging to make evaluations of the new coupled system’s behavior. An experimental model of the test article is developed through modal impact testing, without the need of a shaker. This experimental model is then coupled to a 4-DOF lumped-parameter electromechanical shaker model through dynamic substructuring. The coupled system can then be used for shaker capability estimation for a specific test configuration. By utilizing a modal test and substructuring to estimate performance, no time is lost with the article on the shaker determining if a test specification is achievable. Beyond time savings, the modal model could be coupled to multiple shaker models to determine the best machine for a given test.