Light weight solar panel development Final report
Environmental and vibration tests of lightweight solar panel
Lackey, J. A.↗
SEARCH · Engineering Papers
Results for “vibration testing”
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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Improved relay chatter detector
Detector provides go/no-go sensing of momentary relay or contact opening during vibration testing. Device compares duration of unwanted openings to calibrated standard and lights indicator if standard is exceeded. Stability and reliability are higher than in any other comparable device.
Reynolds, R. K.↗
Space shuttle TPS panel vibration studies
Vibration tests of space shuttle panels at room temperature
Carden, H. D.↗
Peak acceleration limiter for vibrational tester Patent
Electronic detection system for peak acceleration limits in vibrational testing of spacecraft components
Chapman, C. P.↗
Design of SERT 2 spacecraft structures
Design constraints, design description, handling and fabricating, and shock and vibration testing of SERT 2 spacecraft structures
Sharp, G. R.↗
Effects of vibration and shock on the performance of gas-bearing space power Brayton cycle turbomachinery. 1 - Half- sine shock and sinusoidal vibration
Half-sine shock and sinusoidal vibration tests of gas bearing supported rotor assembly and effects on mechanical performance of Brayton cycle space-power turbomachinery
Curwen, P. W.↗
Analytical and experimental studies of natural vibrations modes of ring-stiffened truncated-cone shells with variable theoretical ring fixity
Experimental and analytical investigations of the vibratory behavior of ring-stiffened truncated-cone shells are described. Vibration tests were conducted on 60 deg conical shells having up to four ring stiffeners and for free-free and clamped-free edge constraints and 9 deg conical shells, for two thicknesses, each with two angle rings and for free-free, free-clamped, and clamped-clamped edge constraints. The analytical method is based on linear thin shell theory, employing the Rayleigh-Ritz method. Discrete rings are represented as composed of one or more segments, each of which is a short truncated-cone shell of uniform thickness. Equations of constraint are used to join a ring and shell along a circumferential line connection. Excellent agreement was obtained for comparisons of experimental and calculated frequencies.
Naumann, E. C.↗
Performance of a 10 mlb biowaste resistojet.
Description of the thrusting performance of a 10-mlb thrust, concentric-tubes biowaste resistojet, which was life tested on hydrogen and ammonia propellants for 8000 hours. Thrusting performance is presented for H2, H2O, CH4, and CO2 as well as typical biopropellant mixtures CO2-CH4, H2O-CH4 and CO2-H2O. Using Pt-Ir alloy heater tubes, 235 and 575 seconds were obtained for water and hydrogen propellants. Overall total power efficiencies were 66%, which includes losses for a preevaporator close-coupled for the water tests. Vibration to 1.0 sq q/Hz with an overall G rms of 36, shock at 30 g's and acceleration to 8 g's simulating a launch were passed by the thrustor.
Phillips, D. G.↗
Panel flutter
Criteria are presented for the prediction of panel flutter, determination of its occurrence, design for its prevention, and evaluation of its severity. Theoretical analyses recommended for the prediction of flutter stability boundaries, vibration amplitudes, and frequencies for several types of panels are described. Vibration tests and wind tunnel tests are recommended for certain panels and environmental flow conditions to provide information for design of verification analysis. Appropriate design margins on flutter stability boundaries are given and general criteria are presented for evaluating the severity of possible short-duration, limited-amplitude panel flutter on nonreusable vehicles.
Dowell, E. H.↗
Vibration characteristics of aluminum plates reinforced with boron-epoxy composite material.
Analytical and experimental data on the vibration characteristics of cantilevered winglike flat trapezoidal aluminum plates are presented. The plates had been reinforced with boron-epoxy composite material which had been placed symmetrically about the plate middle surface. The effect of filament orientation on the mode shapes and frequencies of the first ten modes and on the damping coefficients of several of the lowest frequency modes has been investigated experimentally. Experimental data are compared with results from a finite-element analysis. Stiffness properties of the composite material for use in the analysis were determined from vibration tests of composite reinforced aluminum beams.
Clary, R. R.↗
An investigation of hydraulic-line resonance and its attenuation
An investigation of fluid resonance in high-pressure hydraulic lines has been made with two types of fluid dampers (or filters) installed in the line. One type involved the use of one or more closed-end tubes branching at right angles from a main line, and the other type was a fluid muffler installed in-line. These devices were evaluated in forced vibration tests with oscillatory disturbances over a 1000-Hz range applied to one end of the line and with oscillatory pressures measured at various stations along the main pipe. Limited applications of acoustic-wave theory to the branched systems are also included. Results show varying attenuations of pressure perturbations, depending on the number and location of branches and the type of muffler. Up to three branches were used in the branch-resonator study, and the largest frequency range with maximum attenuation was obtained for a three-branch configuration. The widest frequency ranges with significant attenuations were obtained with two types of fluid mufflers.
Sewall, J. L.↗
Response analysis of an automobile shipping container
The design and development of automobile shipping containers to reduce enroute damage are discussed. Vibration tests were conducted to determine the system structural integrity. A dynamic analysis was made using NASTRAN and the results of the test and the analysis are compared.
Hua, L.↗
Correlation of finite-element structural dynamic analysis with measured free vibration characteristics for a full-scale helicopter fuselage
The correlation achieved with each program provides the material for a discussion of modeling techniques developed for general application to finite-element dynamic analyses of helicopter airframes. Included are the selection of static and dynamic degrees of freedom, cockpit structural modeling, and the extent of flexible-frame modeling in the transmission support region and in the vicinity of large cut-outs. The sensitivity of predicted results to these modeling assumptions are discussed. Both the Sikorsky Finite-Element Airframe Vibration analysis Program (FRAN/Vibration Analysis) and the NASA Structural Analysis Program (NASTRAN) have been correlated with data taken in full-scale vibration tests of a modified CH-53A helicopter.
Kenigsberg, I. J.↗
Study of modal coupling procedures for the shuttle: A matrix method for damping synthesis
The damping method was applied successfully to real structures as well as analytical models. It depends on the ability to determine an appropriate modal damping matrix for each substructure. In the past, modal damping matrices were assumed diagonal for lack of being able to determine the coupling terms which are significant in the general case of nonproportional damping. This problem was overcome by formulating the damped equations of motion as a linear perturbation of the undamped equations for light structural damping. Damped modes are defined as complex vectors derived from the complex frequency response vectors of each substructure and are obtained directly from sinusoidal vibration tests. The damped modes are used to compute first order approximations to the modal damping matrices. The perturbation approach avoids ever having to solve a complex eigenvalue problem.
Hasselman, T. K.↗
Specification and correlation of the sine vibration environment for Viking '75
Two Viking spacecraft will be individually launched on a new Titan IIIE/Centaur D-1T launch vehicle in August 1975. The method for the establishment of spacecraft sine vibration test levels prior to availability of any Titan IIIE/Centaur D-1T flight data by use of both computer simulations and data from previous Titan and Atlas Centaur vehicles is described. The specification level is compared with actual flight data obtained from a proof flight launch of the Titan IIIE/Centaur D-1T and a Viking dynamic simulator in January 1974. An objective of the proof flight launch was to obtain estimates of the flight loads and environments. The criteria used to minimize the structural weight that would result from an unmodified application of a sine test environment are described.
Snyder, R. E.↗
Pulse detector
Simple device spots opens and shorts during shock and vibration testing. Device has excellent temperature stability and consistent timing accuracy. Range of detected pulse widths, or time intervals is adjustable.
Simmons, N. E.↗
Revitalizing the hydrodynamic support for space shuttle
The condition of the equipment retained from the Saturn V hydrodynamic support (HDS) is described along with the work necessary to supplement, modify, and refurbish it for the space shuttle mated vehicle ground vibration test (MVGVT). The design changes necessary to adapt the Saturn V HDS design for the space shuttle are described and the results of the inventory and inspection are given.
Sholes, G.↗
Further studies of stall flutter and nonlinear divergence of two-dimensional wings
An experimental investigation is made of the purely torsional stall flutter of a two-dimensional wing pivoted about the midchord, and also of the bending-torsion stall flutter of a two-dimensional wing pivoted about the quarterchord. For the purely torsional flutter case, large amplitude limit cycles ranging from + or - 11 to + or - 160 degrees were observed. Nondimensional harmonic coefficients were extracted from the free transient vibration tests for amplitudes up to 80 degrees. Reasonable nondimensional correlation was obtained for several wing configurations. For the bending-torsion flutter case, large amplitude coupled limit cycles were observed with torsional amplitudes as large as + or - 40 degrees. The torsion amplitudes first increased, then decreased with increasing velocity. Additionally, a small amplitude, predominantly torsional flutter was observed when the static equilibrium angle was near the stall angle.
Dugundji, J.↗