Shaping the Frequency Response Function (FRF) of a Multi-Degree-of-Freedom (MDOF) Structure Using Arrays of Tuned Vibrat
Tuned vibration absorbers (TVA) provide passive energy dissipation from their primary structure but are limited to only having significant impact on a single frequency. Many researchers have theoretically determined optimal TVA parameters to build an arra
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Shaping the Frequency Response Function (FRF) of a Multi-Degree-of-Freedom (MDOF) Structure Using Arrays of Tuned Vibration Absorbers (TVA) Campbell R. Neighborgall, Karan Kothari, V. V. N. Sriram Malladi, Pablo Tarazaga, Sai Tej Paruchuri, and Andrew Kurdila
Abstract Tuned vibration absorbers (TVA) provide passive energy dissipation from their primary structure but are limited to only having significant impact on a single frequency. Many researchers have theoretically determined optimal TVA parameters to build an array of varied sized TVAs to absorb a range of frequencies and ultimately flatten an entire peak of a structure’s frequency response function (FRF). These theoretical approaches often only considered the primary structure to have a single degree-of-freedom and did not consider material and spatial constraints that would normally arise in physical implementation. This study provides the method and results of designing and implementing multiple arrays of TVAs to flatten the FRF at and around both modal frequencies of a two-degree-of-freedom (2DOF) structure. The host 2DOF structure is comprised of two small wooden blocks supported by four thin aluminum posts in a two-story setup with base excitation. A total of 20 TVAs were attached to each primary mass—ten targeting frequencies around the low-frequency mode and ten targeting frequencies around the high-frequency mode. The TVAs were cantilever beams made of varied length dry fettuccini pasta with some including modeling-clay tip masses. The final design successfully reduced the original 2DOF structure’s first natural frequency response by more than 9 dB and second natural frequency response by more than 19 dB for both primary masses. Keywords Vibration absorbers · Pasta · Multiple degrees-of-freedom · Demo · Tuning
33.1 Introduction Tuned Vibration Absorbers (TVAs) are widely used to minimize the response of structures. However, TVAs are most useful when the frequency of operation is fixed. Furthermore, the addition of a TVA to a host structure adds another degreeof-freedom, which creates an additional peak to the frequency response of the system. Tunable piezoceramic vibration absorbers have been proposed to overcome this shortcoming. By changing the parameters of the shunt circuit attached to the piezoceramic, the vibration absorber can be tuned for different frequency of operation [1, 2]. However, active control techniques are necessary for tuning the piezoceramic vibration absorber. Vibrations researchers approached this problem from a different perspective and investigated ways to eliminate the peaks from the frequency response of a system. Attaching an array of linear TVAs to a host structure was shown to be an effective method to reduce the resonant peaks of the system, thus increasing the range of operation [3–6]. The application of multiple absorbers for broadband frequency attenuation complicates the design process. Vignola et al. [3] showed that the design process could be simplified by assigning distribution functions to the structural parame
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