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Results for “VIBRATION MEASUREMENT”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1965

C2 Swan bands in comets

Relative population calculation of vibration levels of electronic levels assuming fluorescence mechanism for carbon-carbon bond Swan bands in comets

SWAN BAND↗
NASA NTRS1966

Model studies of the dynamics of launch vehicles.

Structural dynamics research on launch vehicles at Langley Research Center, examining analytical method limitations and need for improved mathematical models for vibrational characteristics

LAUNCH VEHICLE↗
NASA NTRS1972

Effects of experimentally measured pressure oscillations on the vibration of a solid rocket motor

Results are presented of firing a Nike rocket against a backstop for the purpose of obtaining pressure fluctuations in the rocket case and determining their relationship to structural vibrations of the case. Special care was required to obtain these pressure fluctuations because of the much higher static pressure generated in the rocket. Very small pressure fluctuations within the rocket case can cause significant vibration levels. A previously observed high frequency was shown to decrease with time before completely disappearing at about 1 second of burning time. The vibration of the case itself is probably related to the longitudinal structural modes at frequencies below 500 Hz and is dependent on local structural conditions at frequencies above this value.

Schoenster, J. A.↗
NASA NTRS1972

Microwave spectrum of cis-glyoxal.

The rotational spectrum of glyoxal has been investigated in the region from 18.0 to 40.0 GHz. Only B-type transitions were observed. Both Q-branch and R-branch assignments have been made for the ground state, and the Q-branch assignment has been made for the first excited state of the internal rotational mode. From relative intensity measurements of vibrational excited states, the torsional vibration is found to have a frequency of 114 plus or minus 8 per cm. From a consideration of the rotational constants, it is concluded that the isomer giving rise to the microwave spectrum is the planar cis form and not the gauche isomer. The dipole moment was determined to be 4.8 plus or minus 0.2 D.

Durig, J. R.↗
NASA NTRS1975

Experimental evaluation of multiplane-multispeed rotor balancing through multiple critical speeds

The experimentally proven range of application of the influence-coefficient balancing method, especially the least-squares procedure, is extended to include the case of multiple bending critical speeds within the operating range of a test rotor. Tests were conducted on a laboratory quality machine capable of speeds up to 18,000 rpm in order to investigate several distinct practical aspects of flexible-rotor balancing. These include: (1) balancing for operation through four bending critical speeds, (2) balancing of rotors mounted in both rigid and flexible bearing supports, (3) balancing of rotors with various amounts of measured vibration-response data and different numbers of correction planes, and (4) balancing of rotors with different arbitrary initial-unbalance configurations. The results show that a lightly damped, flexible rotor can be balanced systematically and efficiently through four bending critical speeds. It is concluded that the influence-coefficient method should be equally applicable to rotors or shafts having more than four bending critical speeds in their operating-speed ranges.

Tessarzik, J. M.↗