BLOCK-SHEAR STRENGTH
OF ADHESIVE BONDS
(ASTM D 4501)
Model No. CU-BS (low
carbon steel)
Model No.
WTF-BS (17-4PH stainless)
The ASTM D 4501 Block-Shear Test
Method (Reference 1) describes a procedure and test fixture used to
determine the shear strength of an adhesive used to bond materials
with moduli higher than the modulus of the adhesive. This is not
very restrictive since most practical adherends are stiffer than
most adhesives.
Two blocks
of specific sizes are bonded together and the force required to
shear them apart is measured using the fixture shown below. A
typical test specimen consists of a 1” x 1” block, typically up to
½” thick, bonded in the center of a 3” x 3” block, also typically up
to ½” thick. The block thicknesses are not critical.
Assembled
Fixture without Specimen
The toggle clamp is used to hold
the larger block in place in the main body of the fixture, against
the front plate. The smaller block is positioned in the opening in
the guillotine bar, which is temporarly held in the proper position
for specimen insertion by the thumb screw shown in the front face
plate. This thumb screw is loosened before the test is started.
The fixture is gripped at top and bottom in standard tensile grips
in the testing machine.
The guillotine
bar is shown removed from the fixture in the photograph below, so
that its configuration can be more readily seen.
Block-Shear
Fixture with Guillotine Bar Removed
Source
of Additional Information:
1)
1)
ASTM Standard D 4501-01 (2001), “Standard Test Method for
Shear Strength of Adhesive Bonds Between Rigid Substrates by the
Block-Shear Method, American Society for Testing and Materials, West
Conshohocken, Pennsylvania (first published in 1985).
