NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Z-2 Threaded Insert Design and TestingNASA's Z-2 prototype space suit contains several components fabricated from an advanced hybrid composite laminate consisting of IM10 carbon fiber and fiber glass. One requirement was to have removable, replaceable helicoil inserts to which other suit components would be fastened. An approach utilizing bonded in inserts with helicoils inside of them was implemented. During initial assembly, cracking sounds were heard followed by the lifting of one of the blind inserts out of its hole when the screws were torqued. A failure investigation was initiated to understand the mechanism of the failure. Ultimately, it was determined that the pre-tension caused by torqueing the fasteners is a much larger force than induced from the pressure loads of the suit which was not considered in the insert design. Bolt tension is determined by dividing the torque on the screw by a k value multiplied by the thread diameter of the bolt. The k value is a factor that accounts for friction in the system. A common value used for k for a non-lubricated screw is 0.2. The k value can go down by as much as 0.1 if the screw is lubricated which means for the same torque, a much larger tension could be placed on the bolt and insert. This paper summarizes the failure investigation that was performed to identify the root cause of the suit failure and details how the insert design was modified to resist a higher pull out tension.
Document ID
20160003485
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Ross, Amy (NASA Johnson Space Center Houston, TX, United States)
Rhodes, Richard (NASA Johnson Space Center Houston, TX, United States)
Jones, Robert J. (ILC Dover Frederica, DE, United States)
Graziosi, David (ILC Dover Frederica, DE, United States)
Ferl, Jinny (ILC Dover Frederica, DE, United States)
Sweeny, Mitch (ILC Dover Frederica, DE, United States)
Scarborough, Stephen (ILC Dover Frederica, DE, United States)
Date Acquired
March 16, 2016
Publication Date
July 10, 2016
Subject Category
Engineering (General)
Metals And Metallic Materials
Report/Patent Number
ICES-2016-217
JSC-CN-35679
Meeting Information
Meeting: International Conference on Environmental Systems
Location: Vienna
Country: Austria
Start Date: July 10, 2016
End Date: July 14, 2016
Sponsors: International Conference On Environmental Systems, Inc. (ICES)
Distribution Limits
Public
Copyright
Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available