Back to Search Start Over

Dynamic load mitigation using negative effective mass structures

Dynamic load mitigation using negative effective mass structures

Authors :
Robert Snyder
James M. Manimala
CT Sun
Scott Bland
Hsin-Haou Huang
Source :
Engineering Structures. 80:458-468
Publication Year :
2014
Publisher :
Elsevier BV, 2014.

Abstract

Structures created by incorporating resonating endo-structures within a load bearing exo-structure forbid dynamic disturbances within a specific frequency range from propagating into them without attenuations. Their dynamic behavior can be characterized using a negative effective mass (NM) density. The suitability of such negative effective mass structures (NMS) as infrastructural building-blocks implicitly less susceptible to both harmonic and broadband impact-type loadings is demonstrated. For harmonic loading, an apparent damping coefficient is derived to compare the degree of attenuation achieved in the wholly elastic NMS to an “equivalent” conventionally damped structure. Parametric studies were used to design and construct a low frequency vibration isolator with tip-loaded cantilever beam resonators that evinced 98% payload isolation at resonance. It was found that the higher the stiffness of the host structure, the narrower the isolation bandwidth is in the vicinity of the resonance frequency. Under impact loading, using a numerical optimization procedure, it was established that resonator frequencies toward the higher end of the incoming spectrum gave better reduction in transmitted peak stress. Compact and efficient resonators were constructed using plate springs with chemically etched reentrant patterns and machined titanium resonator masses. Tests performed using an impact pendulum on a resonator stack attached to a transmission bar, substantiated a peak stress reduction of about 60% and filtering of the resonator frequencies in the transmitted spectrum.

Details

ISSN :
01410296
Volume :
80
Database :
OpenAIRE
Journal :
Engineering Structures
Accession number :
edsair.doi...........160adbe044b1b37ab2b7769524bd2a46
Full Text :
https://doi.org/10.1016/j.engstruct.2014.08.052