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National Advisory Committee for Aeronautics, Technical Notes - The Shear Strength of Aluminum Alloy Driven Rivets as Affected by Increasing D-t Ratios

A decrease in shear strengths for increasing D/t
ratios was shown in a Previous investigation of protrud—
ing—head aluminum alloy rivets in double shear conducted
at Aluminum Research Laboratories in 1942. Since single
shear joints are more common than double shear joints, it
was desirable to extend the investigation to single shear
joints. This report describes the results of this inves—
tigation of single shear Joints and also includes the re-
sults of the previous investigation on double shear Joints

For all specimens buttonahead aluminum alloy rivets
1/2 inch in diameter were used. To obtain a wide range
of shear strengths rivet alloys 535-0, 535-T61, 555—5,
and 178~T were used. The 17S—T rivets were driven immedr-
ately after quenching, and all others were driven in the
tempers indicated. 24S—T alloy plate and sheet were em—
played in thicknesses of 1/2,-3/8, 1/4.3/16, 1/8, 0.081,
and O. 064 inch.

The test panels were made up as shown in the sketch
in figure 1. These panels then were out to provide three
single hutt~strap specimens each 25 inches wide contain—
ing one rivet on each side of the joint. Thicknesses of
main and strap plates were the same except in one group
where the thicknesses of the strap plates were Varied;
while the thickness of the main plates was held constant
at 3/8 inch.

The rivets were driven in 33/64—inch drilled and
reamed holes with cone—point heads except in one case
where flat—driven heads were used.

One of the three specimens from each set of three
for each rivet alloy except 5SS~T was tested in tension
in a 20,000—pound capacity Amsler testing machine (Serial
No. 4725, Type lOSZBDA). Movement of the main plates
relative to the strap plate in this specimen was measured
as indicated in figure 2 by means of fine lines scribed
acr0ss the edges of the plates opp051te the center lines
of the rivets.

The movements were measured as the dis—
placement of this line at the faying surfaces. the read—
ings being taken at four locations with-a hand Brinell
microscope reading direct to 0.1 millimeter and by esti—
mation to 0.02 millimeter. The remaining two specimens
of each group of three were tested in tension in the
40,000—pouhd capacity Amsler testing machine (Serial No.
4318, Type BOZBDA) without any readings for movements of
the plate.