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Results for “Thermal Expansion”

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 343 records · Page 19

Pressure distribution for patchlike contact in seals with frictional heating, thermal expansion, and wear

Sliding contact in seals is known to change at high sliding speed from initially uniform pressure to a deformed state where contact is restricted to small patches of the surface. An earlier analysis of such contact was based upon the assumption of uniform pressure on the small patches. The present study draws upon a thermoelastic influence function to provide simultaneous equations for pressure on subdivisions of the patches. The final result is that at high wear rate (and, consequently, high traversal speed of the patch along the surface of the more conductive body of the contacting pair) the pressure distribution becomes roughly triangular with the maximum pressure toward the leading edge of the patch.

Kilaparti, S. R.↗

Thermal expansion behavior of randomly oriented short carbon fiber reinforced copper composites

Several experiments were carried out on Cu composites with random orientation of short C fibers. The composite with random orientation of short C fibers swelled due to the elastic deformation of the fiber skeleton above 573 K. In a 3-D isotropic composite, the Cu matrix softened above 573 K and was fractured by the repulsive force of C fibers which were elastically deformed and released during heating. Swelling of the composite occurred when the fiber content was greater than or = 20 volume percent or the fiber length exceeded 0.5 millimeters. The addition of carbide-forming elements such as Ti was effective in preventing the swelling.

Kuniya, Keiichi↗

Rod Has High Tensile Strength And Low Thermal Expansion

Thoriated tungsten extension rod fabricated to replace stainless-steel extension rod attached to linear variable-differential transformer in gap-measuring gauge. Threads formed on end of rod by machining with special fixtures and carefully chosen combination of speeds and feeds.

Smith, D. E.↗

Seal accommodating thermal expansion between adjacent casings in gas turbine engine

A casing around a turbine and a casing around discharge nozzles have a concentrically arranged shell portion. The seal contains internal pressure while accommodating eccentric, expansion and axial travel. Arcuate seal segments have one leg sealing against a radial surface extending from the inner shell and the other leg against the outer shell. A linkage guides travel of the segments.

Marra, John J.↗

Induction heating cells with controllable thermal expansion of bladders and methods of using thereof

Disclosed herein are induction heating cells and methods of using these cells for processing. An induction heating cell may be used for processing (e.g., consolidating and/or curing a composite layup having a non-planar portion. The induction heating cell comprises a caul, configured to position over and conform to this non-planar portion. Furthermore, the cell comprises a mandrel, configured to position over the caul and force the caul again the surface of the feature. The CTE of the caul may be closer to the CTE of the composite layup than to the CTE of the mandrel. As such, the caul isolates the composite layup from the dimensional changes of the mandrel, driven by temperature fluctuations. At the same time, the caul may conform to the surface of the mandrel, which can be used to define the shape and transfer pressure to the non-planar portion.

42 ENGINEERING↗