An Investigation of Inspection Criteria for Countersunk Rivets

Citation

Sanders, Lewis B. (1947) An Investigation of Inspection Criteria for Countersunk Rivets. Engineer's thesis, California Institute of Technology. doi:10.7907/X2ZV-8G18. https://resolver.caltech.edu/CaltechETD:etd-12082008-091447

Abstract

An investigation was made of the existing flush rivet inspection criteria and inspection methods to establish a norm for commercial flush riveted joints. Studies were made of thirty-four flush riveted joint load deformation curves to obtain their general characteristics and to establish some correlation of yield load as defined in ANC-5 and as defined in Report on Flush Riveted Joint Strength by ARC Rivet and Screw Allowables Subcommittee (Airworthiness Project 12). The specimens corresponding to the load deformation curves were comprised of 18 machine countersunk joints, 12 double dimple joints and four sub-countersunk joints. Within each type of joints the specimen varied in series of sheet material and thickness, rivet material and rivet size. It is shown that yield load, defined as load giving four percent of rivet diameter joint set, is dependent on d/t ratios, the yield load lowering at increasing d/t values. Also, there are indications that as softer rivet material is used with a given sheet material, the increasing d/t ratios have less adverse effects. There could be made no particular correlation of yield load as defined by load at .005" set with any of the varying parameters. In the case of the double dimple and sub-countersunk joints, no particular conclusions could be reached as the test data was confined to a small range of d/t values. It was concluded from the countersunk rivet data that permanent set based on rivet diameter is a more reasonable yield criterion than permanent set based on an arbitrary constant.

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