Shaker-Amplifier System Characterization

Equipment requirements for ground vibration testing of assemblies, sub-assemblies, and components are dependent on several factors. These include test configuration (e.g., size and mass), equipment performance parameters (e.g., stroke limit), and test architecture (e.g., single-axis or multi-axis). Equipment is historically selected based on similitude to past testing, engineering judgement, and/or rudimentary calculations based on Newton’s second law of physics. From these methods alone it can be challenging to know if all desired test configurations and environments are achievable. As an alternative method to determine if a system is capable of running specific tests, a relationship can be developed between the electrical inputs and physical outputs to the system and used to predict if specific testing can be achieved. This paper explores and begins to quantify the relationship between the physical response of an electrodynamic shaker and DUT with the electrical signals of the power amplifiers and the data acquisition systems. Critical parameters of the system that impact shaker performance are identified using experimental data from three different ground vibration shaker tests. Understanding the relationship between the electrical and mechanical responses of an electrodynamic shaker system can provide test engineers with valuable information on the performance limitations of system, as well as knowledge to better utilize testing equipment resources and predict the testability of a proposed experiment. Objectives for this effort were fulfilled largely through experimental means, including post-processing of experimental data and reporting of findings to develop a knowledge database and technical approach, with an end-goal of developing metrics or tools upon which to base equipment requirements for future testing.