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Torque Limits for Fasteners in CompositesThe two major classes of laminate joints are bonded and bolted. Often the two classes are combined as bonded-bolted joints. Several characteristics of fiber reinforced composite materials render them more susceptible to joint problems than conventional metals. These characteristics include weakness in in-plane shear, transverse tension/compression, interlaminar shear, and bearing strength relative to the strength and stiffness in the fiber direction. Studies on bolted joints of composite materials have been focused on joining assembly subject to in-plane loads. Modes of failure under these loading conditions are net-tension failure, cleavage tension failure, shear-out failure, bearing failure, etc. Although the studies of torque load can be found in literature, they mainly discussed the effect of the torque load on in-plane strength. Existing methods for calculating torque limit for a mechanical fastener do not consider connecting members. The concern that a composite member could be crushed by a preload inspired the initiation of this study. The purpose is to develop a fundamental knowledge base on how to determine a torque limit when a composite member is taken into account. Two simplified analytical models were used: a stress failure analysis model based on maximum stress criterion, and a strain failure analysis model based on maximum strain criterion.
Document ID
20020068841
Acquisition Source
Marshall Space Flight Center
Document Type
Contribution to a larger work
Authors
Yi Zhao
(Michigan Technological University Houghton, Michigan, United States)
Date Acquired
August 20, 2013
Publication Date
July 1, 2002
Publication Information
Publication: Research Reports-2001 NASA/ASEE Summer Faculty Fellowship Program
Publisher: Marshall Space Flight Center
Volume: NASA/CR-2002-211840
Issue Publication Date: July 1, 2002
Subject Category
Mechanical Engineering
Funding Number(s)
CONTRACT_GRANT: NAG8-1786
Distribution Limits
Public
Copyright
Public Use Permitted.
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