Design,fabrication and vibration analysis of a lightweight head expander for a high frequency electrodynamic shaker

Head expanders provide an important interface connection between the armature of a vibration shaker and test objects. The most important parameters are the mass of the test specimen and the resonance frequency of the head expander. For that reason determining the natural frequency of the head expander is essential. Moreover, the mass of the head expander had to be lightweight. A head expander for an LDS V450 model electrodynamic vibration shaker was designed and manufactured using AZ91D magnesium alloy to be as light and rigid as possible. The natural frequencies, mode shapes and vibration characteristics of the head expander were determined by performing structural, FE modal and harmonic analyses as well as vibration measurements. Additionally, an experimental modal test was performed and the equipment was subjected to a white noise vibration test to verify all the results. Analyses indicated that the head expander manufactured was light, rigid, durable and suitable for vibration tests.