SACMA
BEARING STRENGTH TEST FIXTURE
(ASTM D 5961)
Model No. CU-LB-SACMA (low
carbon steel)
Model No. WTF-LB-SACMA (17-4PH stainless)
SACMA SRM 9-89, ASTM D 5961, and CMC
Method P6-7 Test Fixture
The so-called
SACMA Bearing Strength Test Fixture (Reference 1) is shown in the
above photograph. This fixture satisfies the requirements of ASTM D
5961 (Reference 2), and has also been adopted by Composite Materials
Characterization, Inc. (Reference 3) as their standard fixture.
ASTM D 5961 actually contains a simpler fixture, which although
functional, is not as convenient to use. This fixture is described
in Section H-3 of this catalog.
The SACMA
version incorporates bushings in housings that can be screwed in and
out to accommodate specimens of varying thickness, as shown in the
above photograph. Thus, no shimming is required. (Two spare pins
are also shown in the photograph.)
The testing
principle is the same for both configurations. A composite laminate
(often quasi-isotropic) of thickness typically in the range of 0.10"
to 0.25" is loaded in bearing by a close fitting ¼” diameter
fastener or pin. The applied load and the associated deformation of
the hole are monitored.
ASTM D 953
(Reference 4), described in Section H-4, also exists. Although
originally developed for testing unreinforced plastics, it has been
used for testing other materials also, as discussed in Section H-4.
Sources of
Additional Information:
1)
1) SACMA Recommended Method SRM 9-89, "Bearing Strength
Properties of Oriented Fiber-Resin Composites," Suppliers of
Advanced Composite Materials Association, Arlington, Virginia, 1989
(now discontinued).
2)
2)
ASTM Standard D5961/D5961M-96 (1996), "Bearing Response of
Polymer Matrix Composite Laminates," American Society for Testing
and Materials, West Conshohocken, Pennsylvania (first issued in
1996).
3)
3)
CMC Screening Method P6-7, "Bolt Bearing Strength Test,"
Composite Materials Characterization, Inc., Richardson, Texas,
Revised June 1999 (first issued in 1994).
4)
4)
ASTM Standard D 953-95 (1995), "Bearing Strength of
Plastics," American Society for Testing and Materials, West
Conshohocken, Pennsylvania (first issued in 1948).
