Mechanical Testing of Shear Pin

[dforce]

I have a 3/4" diameter notched shear pin that I would like to test to determine it's shear strength. My mechanical engineering is a little rusty... could I conduct a simple tesile test on the pin and then convert it to shear strength or is there another test that can be done?
Thanks
D

 

[dvd]

If you aren't concerned with repeatable results the tensile test would give order of magnitude results. I have used shear pins on numerous couplings and find that they are rather sensitive to surface finish and unanticipated peripheral effects, such as bending. I would recommend testing several of the pins in the actual shear pin holding device if you need accurate results.

 

[MintJulep]

I second that. In fact you should test with several carefully chosen holder sets and pins, selected to span the full range of clearance between pin and holder that will be allowed by your component tolerances.

This should allow you to at least quantify the range of shear values that the "unanticipated peripheral effects" will introduce.

 

[cbrn]

Hi,
my advice is: if you want to get acceptably accurate results, don't do a tensile test in order to determine the rupture force (in shear) of your pin.
Rather, reproduce with a suitable machine the real fashion in which the shear-pin is acted.
Moreover, don't test a single specimen: as it has been said, shear-pins are sensitive to the notch diameter, which can vary because of tolerances, to the surface finish (more constant, but who knows...) and to the material characteristics of course (which can vary slightly even in the same bar...).
Where I work we use extensively shear-pins as security devices, and the procedure we follow is like I've said: 5 - 10 specimen from the same bar from which the definitive ones will be taken (this makes a 1-to-4 / 1-to-8 sampling), shear-machine applying the force in the exact same way as the "real" system. Nevertheless, we have frequently 5 to 15% dispersion in the results...

Regards