Analytical analysis of bolted joints requires either the direct calculation of fastener elongation or calculation of the components that determine elongation. In this paper we will use two popular calculation methods to compare these estimates to actual test measurements of elongation. Part 1of this test, published in an earlier issue of Fastener World, summarized the VDI 2230 and Bickford calculations of total elongation and compared tested values to those estimates. In this paper, by testing various combinations of head and nut configurations, we will attempt to separate elongation into its three components: the head, the unrestrained portion of the shank, and the portion of the shank engaged in the nut or nut member. As opposed to the unrestrained portion of the shank, the head and nut transition areas can contain complex stress profiles, which make their elongation difficult to predict.

Dave Archer

Articles

Self-Drilling Screws Aren’t All Created Equal (Nor Are Pointing Dies)

2011-02-23

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