DIY impact tester

[JTknives]

I have considered buying a steel impact tester. Was looking at the un notched tests but it’s a tad out of my price range for a side project. After looking at the design and function it seams like it’s all just math. You have a free swinging weight that’s retracted to X height and released. This has a max over center travel, this would become your 0 point of 0% FT/LBS. The bottom center would be 100% aka did not bust the test so it absorbed all the energy. after this you mount the test strip at the dead center to the apex of energy aka the bottom lol. The hammer will expend energy into the sample when it snaps it. The hammer will now travel as past center and will show the total energy absorbed. Yes that’s a real broad glaze over the math but I don’t see why it would not be something that could be build easily. Any thoughts on this? Any of you guys ever used one of these types of impact testers?

basic math to show the idea.
PE = mgL(1 – COS θ)

 

[Drew Riley]

I've never used one, but I imagine that even if you didn't build to "industry standard", the data you record would still be relative to your own tests, which would still be useful.

 

[JTknives]

I've never used one, but I imagine that even if you didn't build to "industry standard", the data you record would still be relative to your own tests, which would still be useful.

that was my thought as well. But I would like to be able to get some kind of quantifiable data.

 

[PEU]

It may not be certifiable, but you can surely compare results with a certified device and know if its trustable or not.

Pablo

 

[Lieblad]

Looks like a good idea to me.
As you say, its alot of numbers crunching to determine values.
Perhaps pendulum placed in front of a grid or graduated scale, then using a highspeed camera will reveal among other data, hammer speed, material deflection at failure, etc.

 

[JTknives]

Hammer speed would be a good way to calculate energy.