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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS2022

A Quantitative Damage Tolerance Comparison of High Strength and High Modulus Carbon Fiber Sandwich Structure

This study presents experimental results of the compression after impact (CAI) testing of sandwich structure with face sheets made either with IM7/8552 high strength fiber or HM63/8552 high modulus fiber. While the HM63/8552 face sheet sandwich specimens would not be as damage tolerant as the IM7/8552 face sheet sandwich specimens, a quantitative measure of how much more damage tolerant the IM7/8552 face sheets were than the HM63/8552 face sheets was sought. Due to the IM7/8552 face sheets being 28% thicker than the HM63/8552 face sheets, the impact energies used needed to be adjusted for a fair comparison. The results show that the modulus is 35% lower for the IM7/8552 face sheet sandwich structure while the CAI strength

High modulus carbon fiber↗
NASA NTRS1965

Anisotropic strength of composites.

Strength of anisotropic composite materials subjected to any state of combined stress, predicted from basic strength characteristics of unidirectional layer

COMPOSITE MATERIAL↗
NASA NTRS1966

On deformation and strength.

Mechanical strength of medium formulated as microscopic behavior in continuum obtaining time- dependent macroscopic fracture strength

TENSILE STRENGTH↗
NASA NTRS2012

Aerospace Threaded Fastener Strength in Combined Shear and Tension Loading

A test program was initiated by Marshall Space Flight Center and sponsored by the NASA Engineering and Safety Center to characterize the failure behavior of a typical high-strength aerospace threaded fastener under a range of shear to tension loading ratios for both a nut and an insert configuration where the shear plane passes through the body and threads, respectively. The testing was performed with a customized test fixture designed to test a bolt with a single shear plane at a discrete range of loading angles. The results provide data to compare against existing combined loading failure criteria and to quantify the bolt strength when the shear plane passes through the threads.

Threaded fastener↗
NASA NTRS2022

The Effects of Co-cured Versus Precured Carbon/Epoxy Face Sheets on the Modulus and Compression After Impact Strength of Honeycomb Sandwich Structure

This study presents experimental results of compression after impact (CAI) and stiffness testing of aluminum honeycomb core sandwich structure with quasi-isotropic face sheets that have either been co-cured or precured (and then bonded to the core in a secondary operation). The co-cured face sheets contain some ply waviness whereas the precured face sheets did not. The effect of this waviness was ascertained for two important design parameters for the Space Launch System (SLS) Payload Adapter Fitting (PAF); compressive modulus and CAI strength. It was found that there was no effect on the modulus between co-cured and precured face sheets using the material and processes in this study. In addition, there was no difference in CAI strength behavior between the co-cured and precured face sheet.

sandwich structure↗
NASA NTRS1969

High strength, superplastic superalloy

High strength superplastic superalloys are produced by extruding a pre-alloyed powder. The cast nickel base superalloy was remelted and converted to pre-alloyed powder by inert gas atomization. The superalloy shows high tensile strength and superplasticity and finds use in hot working and casting.

Ashbrook, R. L.↗
NASA NTRS1969

Improved high-temperature-strength nickel-base superalloy

Nickel-base superalloy has a strength of 20,000 psi at 2,200 degrees F, approximately double the strength of the strongest available cast nickel-base alloys. It is not subject to the formation of embrittling phases upon long time exposure at intermediate temperatures.

Freche, J. C.↗
NASA NTRS1969

Nondestructive determination of cohesive strength of adhesive-bonded composites

Systematic plan determines vibration responses and modes of honeycomb composites, correlates vibrational responses of composite specimens varying in strength of cohesive bond, determines effects of thickness variation of the face sheet over the frequency range, optimizes the characteristics of the excitation transducer, and measures bond strength.

Thompson, D. O.↗
NASA NTRS1971

C-130: Results of center wing residual strength and crack propagation test program

Fourteen C-130 airplane center wings which had experienced from approximately 4,000 to 13,000 hours of flight service and its associated fatigue damage were tested to destruction, seven in upbending and seven in downbending. Six wings were tested directly for static residual strength in the fatigue-damaged condition as received from field service. The other eight wings were tested in crack propagation cyclic testing at a prescribed stress level for a maximum of 10,000 cycles. Then the stress level was reduced and testing was continued up to a maximum of 20,000 total cycles. Cyclic testing was performed with constant-amplitude stresses at a stress ratio of +0.1. Maximum cyclic skin stresses were approximately 18,000 psi. At the conclusion of cyclic testing, a static test to destruction was conducted to determine the residual strength of each fatigue-damaged specimen.

Reeder, F. L.↗
NASA NTRS1971

Determining and analyzing the strength and impact resistance of high modulus glass

An error was noticed recently in the computer program used to reduce the laboratory sonic measurements to tabulated values of Young's modulus of the bulk samples of experimental glasses. Correction of this error gave revised values for the last fifty experimental glasses prepared in this laboratory. This corrected data, when examined as input material for the calculation of Young's modulus of bulk glasses from composition by the C. J. Phillips procedure, resulted in new values for the contribution per mol of several oxides. The new value for the zinc oxide molal factor is especially significant since it is slightly greater than the factor for beryllia for the types of glasses melted in the UARL research program. This discovery provides a new tool in the search for nontoxic, i.e. without beryllia, high modulus glass fibers particularly when coupled with recent measurements that showed zinc oxide contributes significantly to increased impact strength. New glass compositions prepared in this period and the latest impact strength values measured are also included.

Bacon, J. F.↗