Rich Barrett and the Fastener Design Manual
The late Rich Barrett -- he passed away in 2008 -- was the author of NASA's Fastener Design Manual, distributed by NASA to companies and organizations worldwide, and credited with saving the United States Government millions of dollars in engineering effort and failure risk. His original Manual has been published here with his permission and in his honor.
He was the only NASA representative ever to win the Federal Laboratory Consortium Award for Technology Transfer, and served on the National Aerospace Standards Committee for Fasteners, the Bolting Technology Council, and the MIL HDBK-5 Committee. He once had a regular column, "Ask the Expert," in the American Fastener Journal.
Since Rich died, I have received numerous requests for help from well-meaning people wanting Rich's advice. I'm sorry -- he's passed on, and I don't have his skill. I used to send such people polite notes, but there's no time for that any more. If the Manual doesn't help, I don't know what else I can tell you.
Fastener Design Manual, part one
Fastener Design Manual, part two
Fasteners in Shear
The following is a Java applet I wrote to enable you to interactively calculate the resultant reaction from a force acting in shear on a pattern of fasteners. (I got the technique from Rich while he was alive.)
- To the left of the "Set Force" button, give your force in x- and y-coordinates, as INTEGERS. When you click the button, an arrow indicating the force appears.
- To the left of the "Add Fastener" button, give the x- and y-coordinates of a fastener in the pattern you wish to examine, as INTEGERS. When you click the button, a circle indicating the fastener appears.
- When you have at least one fastener, a reaction force appears, if you've set a force as indicated above. If the force is zero, there's no reaction.
- When you have two or more fasteners in the pattern, an X indicating the pattern centroid appears. If you've set a force as indicated above, you'll see two reactions: one for direct shear and one for shear induced by the moment about the pattern centroid.
- The applet is unitless; you only have to be consistent to get meaningful results.
- The reset button will eliminate the force and the fastener pattern; you use it to start over.
- This applet is using the Java default coordinate system -- which means that the +y-direction is DOWN, not UP. (Java's reference -- as is the case for online graphics -- is the upper left corner of the image.)
- The applet is currently limited to 20 fasteners. We hope that's enough. :-)