Loading patent…
AssigneeHughes Aircraft Company
InventorCharles F. Talbott, Jr.
Estimating the term…
Pneumatically driven vibrators coupled to resonating, self-attenuating structures define a shaker which, when included in a vibration system, enables a test item to be vibration tested under controlled conditions of multi-frequency, multi-degree-of-freedom acceleration history, to achieve a frequency spectrum and acceleration-level control of a broadband quasi-random vibration output in the frequency range, for example, from 40 Hz to 2 kHz for vibration testing of equipment. The driving set of annular structure responds to an intense vibration spectrum, created by the attached pneumatic vibrators, with multi-modal forced and resonant frequencies in limited directions. The driven set of annular structure, holding the test hardware, responds with forced and harmonic oscillations to a vibration field transmitted from the driving set of structure through a specially designed elastomeric path. Specific design of the size, mass, and resonant behavior of the driving and driven structure sets with appropriate transmissibility characteristics of the elastomeric interface results in a controlled multi-modal, uniform RMS acceleration, multi-degree-of-freedom, wide-frequency-range vibration testing method. The annular arrangement of structure takes advantage of the complex amplitude-displacement behavior of the circumference of a ring excited into multi-modal in-plane and out-of-plane bending and torsional activity by the attached vibrators. Changes in pneumatic vibrator operating pressure change vibrator frequencies and expand available modal density.
A shaker for vibration testing of a test item comprising an annular driving structure, an annular driven structure supporting the test item, a visco-elastic structure coupling said driving and driven structures together, and means coupled to said driving structure for imparting vibratory excitations thereto.
In a vibration system having means for supporting a test item including a platform on which said test item is positioned, and a driving member, a driven member, and visco-elastic material coupling said driving and driven members together;
A method for quasi-randomly varying vibration frequencies applied to a test item comprising the steps of producing and varying frequencies, utilizing the frequencies for an excited, time-varying combination of bending and torsional structure behavior and visco-elasticity of elastomers for superimposing multimodal, multi-phase, multi-directional simultaneously produced quasi-random vibrations, and applying the vibrations to the test item.
Dependencies are inferred from the claim text.