Search NASA⌕ Search

SEARCH · Search NASA

Results for “Zinc Spelter Sockets”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

3 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2021

NASA Engineering and Safety Center Technical Bulletin No. 21-05: Industry Recommendations from Arecibo Observatory Zinc Spelter Socket Joint Failure Analysis

A structural analysis and forensic investigation concluded that the Arecibo Observatory M4N socket joint failure in August 2020 was primarily due to cumulative damage caused by initially low structural design margins and a high percentage of sustained load, resulting in zinc creep deformation, progressive internal socket wire damage, and eventual loss of joint capacity. Open spelter sockets of this type are used throughout industry in stay cables. Recommendations are proposed to prevent failures of similar socket joints, including verification of positive stress margins in socket joint wires for all failure modes, periodic visual inspections with pass/fail criteria for zinc extrusion that are tied to structural qualification, and revisiting codes/ industry standards to capture lessons learned.

Arecibo Observatory↗
NASA NTRS2021

Arecibo Observatory Auxiliary M4N Socket Termination Failure Investigation

The NASA Engineering and Safety Center (NESC) was requested to support the Arecibo Observatory failure investigation in determining the root cause of the Auxiliary M4N cable failure. The NESC and Kennedy Space Center led an integrated NASA investigation with support from Marshall Space Flight Center and The Aerospace Corporation that included forensic investigation of failed hardware, finite element modeling, materials characterization, and root cause analysis. This document contains the outcome of the NESC Assessment.

Zinc Spelter Sockets↗
NASA NTRSDate not supplied

Structural Analysis Findings of Open Spelter Socket Cable Terminations

A three-dimensional nonlinear finite element model of a representative open spelter socket termination was developed to examine the underlying mechanics of load transfer from a structural cable through the termination, the sensitivity of the joint design to wire brooming, zinc material nonlinearity, contact friction between the zinc and socket, voids within the zinc, and, finally, the effects of repeated loading on the joint. Primary factors affecting open spelter socket design are cast zinc plastic flow, depth of zinc slug seating, and quality of wire brooming. Zinc plasticity and proper brooming allows for efficient load transfer by developing confining pressure on the broomed wires in the narrow part of the socket, which keep the wires from pulling out of the zinc and shift failure to occur outside the socket. Highest wire stresses in the cable occur in the outer ring adjacent to the termination. While industry use of stay cables are typically designed to carry less than half the rated breaking force in aggregate, the constituent stresses within the zinc and the wires have the potential to exceed their respective allowable in operation and should be evaluated for fatigue- and creep-critical applications.

Pavel Babuska↗