Machinery's Handbook, 31st Edition
1862 Riveted Joints Rivet Material: Rivets for structural and machine-member purposes are usually made of wrought iron or soft steel, but for aircraft and other applications where light weight or resistance to corrosion is important, copper, aluminum alloy, Monel, Inconel, etc., may be used as rivet material. Simplified Design Assumptions: In the design of riveted joints, a simplified treatment is frequently used in which the following assumptions are made: 1) The load is carried equally by the rivets. 2) No combined stresses act on a rivet to cause failure. 3) The shearing stress in a rivet is uniform across the cross section under question. 4) The load that would cause failure in single shear would have to be doubled to cause failure in double shear. 5) The bearing stress of rivet and plate is distributed equally over the projected area of the rivet. 6) The tensile stress is uniform in the section of metal between the rivets. Failure of Riveted Joints.— Rivets may fail by: 1) Shearing through one cross section (single shear) 2) Shearing through two cross sections (double shear) 3) Crushing Plates may fail by: 4) Shearing along two parallel lines extending from opposite sides of the rivet hole to the edge of the plate 5) Tearing along a single line from middle of rivet hole to edge of plate 6) Crushing 7) Tearing between adjacent rivets (tensile failure) in the same row or in adjacent rows Types 4 and 5 failures are caused by rivets being placed too close to the edge of the plate. These types of failure are avoided by placing the center of the rivet at a minimum of one and one-half times the rivet diameter away from the edge.
Single Shear of Rivet
Double Shear of Rivet
Shearing of Plate
Crushing of Plate or Rivet Tearing of Plate to Margin Types of Rivet and Plate Failure
Tearing Between Rivets
Failure due to tearing on a diagonal between rivets in adjacent rows when the pitch is four times the rivet diameter or less is avoided by making the transverse pitch one and three-quarters times the rivet diameter. Theoretical versus Actual Riveted Joint Failure: If it is assumed that the rivets are placed the suggested distance from the edge of the plate and each row the suggested distance from another row, then the failure of a joint is most likely to occur as a result of shear failure of the rivets, bearing failure (crushing) of the plate or rivets, or tensile failure of the plate, alone or in combination depending on the makeup of the joints. Joint failure in actuality is more complex than this. Rivets do not undergo pure shear especially in lap-joints where rivets are subjected to single shear. The rivet, in this instance,
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online