Optimal design of head expander for a lightweight and high frequency vibration shaker

Abstract

Vibration testing requires the head expander to interface with both the test component and vibration shaker. At times, head expanders have resonant frequencies over the frequency range of interest. The moving mass will also have an influence on the shakers thrust ability during vibration testing. In order to ensure a successful vibration test, it is necessary to observe the resonant frequency and mass of the head expander. The aim of this study is to optimize the shape and size of the head expander with a lightweight and an improved resonant frequency. This was achieved using a FE modal analysis and design of experiments (DOE). Firstly, the vibration characteristics, such as the resonant frequencies and mode shapes of the baseline model were estimated using a FE modal analysis. In order to validate the FE modal analysis, a modal test was performed and the test results were then compared with those from the FE analysis. Secondly, three shapes of head expander were suggested to select the geometry with the best vibration characteristics, and the design variables of the head expander were defined. The vibration characteristics of the three geometries and their design variables were assessed in terms of their weights and resonant frequencies. Finally, optimization process was performed to find a minimum mass within the target frequency and diameter of platform plate. The coefficients from the regression equation for the objective function were calculated to provide optimized data for the vibration shaker head expander.