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At least 73 records · Page 4

All sources NASA NTRS DOE OSTI

NASA NTRS2000

Composite fastener for use in high temperature environments

A fastener includes a composite body and a metal coupling attached to the body. The metal coupling includes an attachment structure to connect the fastener to an external structure. An assembly of components includes a first metallic component having a first coefficient of thermal expansion, a second non-metallic component having a second coefficient of thermal expansion different from the first thermal expansion and having a groove that receives a fastener that extends between the groove and the second component, the fastener slidably engaging the groove to accommodate relative expansion between the components.

Miller, Robert J.↗

NASA NTRS2016

Prevailing Torque Locking Feature in Threaded Fasteners Using Anaerobic Adhesive

This paper presents results from tests to assess the use of anaerobic adhesive for providing a prevailing torque locking feature in threaded fasteners. Test procedures are developed and tests are performed on three fastener materials, four anaerobic adhesives, and both unseated assembly conditions. Five to ten samples are tested for each combination. Tests for initial use, reuse without additional adhesive, and reuse with additional adhesive are performed for all samples. A 48-hour cure time was used for all initial use and reuse tests. Test data are presented as removal torque versus removal angle with the specification required prevailing torque range added for performance assessment. Percent specification pass rates for the all combinations of fastener material, adhesive, and assembly condition are tabulated and reveal use of anaerobic adhesive as a prevailing torque locking feature is viable. Although not every possible fastener material and anaerobic adhesive combination provides prevailing torque values within specification, any combination can be assessed using the test procedures presented. Reuse without additional anaerobic adhesive generally provides some prevailing torque, and in some cases within specification. Reuse with additional adhesive often provides comparable removal torque data as in initial use.

Hernandez, Alan↗

NASA NTRS2016

Mounting Systems for Structural Members, Fastening Assemblies Thereof, and Vibration Isolation Systems Including the Same

Mounting systems for structural members, fastening assemblies thereof, and vibration isolation systems including the same are provided. Mounting systems comprise a pair of mounting brackets, each clamped against a fastening assembly forming a mounting assembly. Fastening assemblies comprise a spherical rod end comprising a spherical member having a through opening and an integrally threaded shaft, first and second seating members on opposite sides of the spherical member and each having a through opening that is substantially coaxial with the spherical member through opening, and a partially threaded fastener that threadably engages each mounting bracket forming the mounting assembly. Structural members have axial end portions, each releasably coupled to a mounting bracket by the integrally threaded shaft. Axial end portions are threaded in opposite directions for permitting structural member rotation to adjust a length thereof to a substantially zero strain position. Structural members may be vibration isolator struts in vibration isolation systems.

Young, Ken↗

NASA NTRS1972

The Alcoa ram fastener: A reusable blind rivet

Results of tensile, shear, fatigue and accelerated weathering tests are presented for the ram fastener, a reusable, single unit blind rivet. The effects of variations in hole size, grip length and sheet thickness on strength properties of the fastener were determined. The test results show these fasteners to have strength characteristics suitable for light structural applications. Exposure to accelerated weathering did not impair their performance.

Dewalt, W. J.↗

NASA NTRS1975

Development of an advanced high-temperature fastener system for advanced aerospace vehicle application

The results of a program to develop a lightweight high temperature reusable fastening system for aerospace vehicle thermal protection system applications are documented. This feasibility program resulted in several fastener innovations which will meet the specific needs of the heat shield application. Three systems were designed from Hayes 188 alloy and tested by environmental exposure and residual mechanical properties. The designs include a clinch stud with a collar retainer, a weld stud with a split ring retainer, and a caged stud with a collar retainer. The results indicated that a lightweight, reusable, high temperature fastening system can be developed for aerospace vehicle application.

Kull, F. R.↗

NASA NTRS1977

Investigation of threaded fastener structural integrity

Technical nondestructive evaluation approaches to the determination of fastener integrity were assessed. Existing instruments and methods used to measure stress or strain were examined, with particular interest in fastener shank stress. Industry procedures being followed were evaluated to establish fastener integrity criteria.

Source record↗

NASA NTRS1983

Mechanically fastened joints in woven fabric composites

Strength analysis for composite bolted joints involves the mating of a stress analysis with an appropriate mode specific failure criterion for each of the primary failure modes. The stress analysis and failure criteria are independent of each other and can be manipulated separately in order to optimize the strength analysis package formed by their coupling. Material properties tests were conducted on rubber toughened graphite-epoxy material to measure the basic strength and stiffness in the warp and fill directions and in shear. Test matrices are summarized for investigations of laminate configuration, stacking sequence, fastener diameter, edge distance, fastener half spacing, laminate thickness, and fastener torque. A three dimensional finite element analysis computer program was written and failure criteria for net tension, shearout, and bearing were determined.

Wilson, D. W.↗

NASA NTRS1985

Standard Fastener Library

Program for use with graphics system creates library of standard fastener hardware. Programs categorized by fastener geometric shape with tabulated sizes. Fastener details recalled by configuration and size for insertion into drawing on screen. Program used in production of engineering drawings for Space Shuttle orbiter.

Tejwani, J. J.↗

NASA NTRS1985

Daze fasteners

A daze fastener system for connecting two or more structural elements wherein the structural elements and fastener parts have substantially different coefficient of thermal expansion physical property characteristics is employed in this invention. By providing frusto-conical abutting surfaces between the structural elements and fastener parts any differences in thermal expansion/contraction between the parts is translated to sliding motion and avoids deleterious thermal stresses in the connection. An essential feature for isotropic homogeneous material connections is that at least two sets of mating surfaces are required wherein each set of mating surfaces have line element extensions that pass through a common point.

Jackson, L. R.↗

NASA NTRS1987

Quick-Release Panel Fastener

Quick-release fastener for panels actuated with just one hand. Fastener has no loose parts, does not require mating hardware, and used in blind hole in mating panel. New panel fastener selfcontained unit extending through congruent holes in two panels to be joined. Unit contracts to clamp panels together and expands to release them.

Fosdick, D. R.↗

NASA NTRS1987

Daze fasteners

A daze fastener system for connecting two or more structural elements wherein the structural elements and fastener parts have substantially different coefficient of thermal expansion physical property characteristics is employed in this invention. By providing frusto-conical abutting surfaces between the structural elements and fastener parts any differences in thermal expansion/contraction between the parts is translated to sliding motion and avoids deleterious thermal stresses in the connection. An essential feature for isotropic homogeneous material connections is that at least two sets of mating surfaces are required wherein each set of mating surfaces has line element extensions that pass through a common point.

Jackson, L. Robert↗

NASA NTRS1990

Braided Composite Threaded Fasteners

Fasteners of carbon/carbon or other fiber/matrix composite materials made by braiding-and-molding process. Preform of braided fibers impregnated with matrix material pressed and cured in internally threaded, split mold to make externally threaded rod. Process costs less, produces stronger fasteners by avoiding breakage of fibers, and adaptable to mass production. Intended for use with ceramic and composite-material structural parts at temperatures approximately greater than 2,500 degrees F (approximately greater than 1,400 degrees C), at which metal fasteners cannot be used.

Sawyer, James Wayne↗

NASA NTRS1992

Metallic threaded composite fastener

A metallic threaded composite fastener, particularly suited for high temperature applications, has a body member made of high temperature resistant composite material with a ceramic coating. The body member has a head portion configured to be installed in a countersunk hole and a shank portion which is noncircular and tapered. One part of the shank may be noncircular and the other part tapered, or the two types of surface could be combined into a frustum of a noncircular cone. A split collar member made of high strength, high temperature tolerant metal alloy is split into two halves and the interior of the halves are configured to engage the shank. The exterior of the collar has a circumferential groove which receives a lock ring to secure the collar halves to the shank. In the assembled condition torque may be transmitted from the body to the split collar by the engaged noncircular portions to install and remove the fastener assembly into or from a threaded aperture and shear loads in the collar threads are transferred to the shank tapered portion as a combination of radial compression and axial tension loads. Thus, tension loads may be applied to the fastener shank without damaging the ceramic coating.

Dunn, Thomas J.↗

NASA NTRS1994

Hook-And-Loop Metal Fastener

Proposed fastener includes metal loops and hooks repeatedly put together and pulled apart like Velcro (or equivalent) plastic fastener. Strip of hooks stamped from sheet of metal, and tip of each hook bent at right angle to root. Many such strips arrayed in parallel to form hook half of fastener. Each hook twists and bends as loop pulled away.

Sawaf, Bernard↗

NASA NTRS1994

Fastener Caps For Electronic Panels

Simple devices indicate fasteners disturbed. Lid on fastener cap bent to cover fastener head. Caps then wired together in pairs. Used in place of older paper or plastic tape seals, providing greater security and presenting neater appearance.

Peters, Kenneth D.↗

NASA NTRS1995

NASA-Wide Fastener Technical Interchange Meeting

This document summarizes the minutes of the second NASA-Wide Fastener Technical Interchange Meeting (TIM) held November 15-16, 1994, and compiles the viewgraph presentations at the TIM by NASA and contractor personnel. The information in this document may be of value to the NASA and contractor fastener engineering community in determining the fastener controls and initiatives that existed at the time of the TIM.

Gamwell, W. R.↗

NASA NTRS1995

Adjustable Tool For Driving Multiple Fasteners

Proposed tool tightens or loosens several bolts, screws, nuts, or other threaded fasteners arranged in circle on compressor head, automotive wheel, pipe-end flange, or similar object. Combines some features of related mechanism described in, "Tool for Driving Many Fasteners Simultaneously" (MSC-22386). Unique feature of proposed mechanism; lateral positions of output shafts adjusted, by use of mechanism called "selector," to fit fastener patterns with larger or smaller bolt circles. Concept extended from circular pattern to rectangular pattern for application to automobile headers and intake manifolds.

Cook, Joseph S., Jr.↗

NASA NTRS1996

Push/Push Fastener

Modified version of Nylatch (or equivalent) commerical quick-connect/quick-disconnect fastener for joining flat panels. Fastener tightened by pushing on knob on one side and loosened by pushing on knob on other side. Push/push operation of fastener advantageous in cold or otherwise hostile environments where gloves worn, in underwater operations, or if person handicapped.

Jackson, Steven A.↗