Fixed Span Long Beam Flexure Test Fixture (ASTM D7249)

Model No. WTF-LF (Aluminum and Stainless Steel)

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Fig. 1: Fixed Span Long Beam Flexure Fixture

This is a specialized version of the standard Long Beam Flexure Fixture  and includes alignment rods and linear bearings. Rather than being fully adjustable, it is designed for specific loading and support spans. This is sometimes desired in testing environments such as production quality control, to insure that the proper spans are consistently being used and cannot be altered.

The fixture shown is set up for four-point loading, with a three-point loading head shown in the center foreground.  Various optional support and loading configurations are shown including wide flat supports and cylindrical supports.  The optional stops shown are attached to the flats, to permit ease of centering the test specimen.

Typically, up to three different loading and support spans can be specified by the customer, with the maximum support span being 24 in. The maximum specimen width can also be specified, being typically between 2 in. and 6 in. As suggested in the above photograph, loading and support pads of any practical configuration can be provided.  Built-in stops to center specimens of various widths can also be provided. This fixture is fabricated primarily of aluminum, to minimize fixture weight,  with hardened steel cylinders and flats for durability.

In use, the fixture can be loaded directly on the top loading plate, or preferably through an optional adapter such as shown, attached to the cross head of the testing machine. For this purpose, a standard Instron Type Dm connection (1.25 in. diameter male stud with a 0.50 in. diameter cross-pin hole) can be provided with the fixture. The fixture base rests unconstrained on the base of the testing machine.