Fastener Bearing Specimen Support Fixture (ASTM D5961, procedure B)

Model No. WTF-SF (Stainless Steel)

IMG_3119

Fig. 1: Partially disassembled Fastener Bearing Specimen Support Fixture

The specimen support fixture shown in Fig. 1 is used with Procedure B – Single Shear, of ASTM D5961 (Reference 1). The bearing strength of a 1.5 in. wide test specimen assembly containing one or two ¼ in. diameter fasteners is to be determined. 

ASTM Standard D5961 also includes Procedure A – Double Shear, Procedure C - Single Shear, and Procedure D - Double Shear-Compression Loading, which are described on a separate page.

The test specimen for Procedure B consists of two identical plates fastened together using one or two centerline fasteners, with a doubler on each end to minimize bending due to eccentricity of the applied force.  This support fixture can be used with either tensile or compressive loading, to stabilize the fixture and further minimize bending effects. Hydraulic wedge grips are used to grip the support fixture at each end, just as discussed in relation to the Boeing Open-Hole Compression Test Fixture, Model WTF-OH (Reference 2).  Tungsten carbide particle specimen gripping surfaces, as can be seen in the opened half of the fixture at the left side of Fig. 1, are used to transfer the applied load from the grips into the specimen.

Both the applied force and the associated deformation of the holes in the specimen plates are monitored, to bearing failure of one or both specimen plates. 

Source of Additional Information:

1) ASTM Standard D5961/5961M-13 (2013), “Standard Test Method for Bearing Response of Polymer Matrix “Composite Laminates,” American Society for Testing and Materials, West Conshohocken, Pennsylvania (first issued in 1996).

2) ASTM Standard D6484/6484M-14 (2014), "Standard Test Method for Open-Hole Compressive Strength of Polymer Matrix Composite Laminates," American Society for Testing and Materials, West Conshohocken, Pennsylvania (first issued in 1999).