Force to push plate through bulk material 1

[evilspeeder]

I'm looking for a way to calculate the force required to move a vertical plate having width .75" through a pile of material with a known density, cross section, and particle top size.

The closest I've been able to come is calculating the force necessary to displace the required volume of material for the plate to slide through. This doesn't take into account the force necessary to move the larger particles (wider than the plate width) out of the way.

Any ideas? Thanks!

 

[FeX32]

In my opinion, you are on the right track. Keep thinking. Some factors worth noting may be:
- what direction is the plat being moved (ie. being pushed horizontally or vertically into the material)
- at what depth is the plate at (if being pushed horizontally)
- would the shear stress on the surface of the plate have a significant affect or not? (possibly depending on the material)

Your mention of particle sizes being larger then the thickness of the plate makes me think that an analytical method probably does not exist. You can try to approximate a force with basic static and dynamical laws. But, I would try to perform a simple experiment to verify. Would be interesting to correlate the 2.






Fe

 

[PeterCharles]

I know you want to calculate it, but from my materials handling experience I'd set up a test and measure it. Science and bulk materials still have a way to go.

 

[davidhaag]

Hi Evilspeeder,

I'd like to help with this problem, but I need some more information. What are the boundary conditions for this problem (i.e. Where can the larger particals flow to that are wider than your plate)? Can you send me a diagram of what you're trying to accomplish? Also, maybe we can simplify it in a manner that yields a conservative answer for the force being calculated. What device is delivering the force to the system? Hope to help!

Regards,

David Haag, M.E.

Haag Enterprises
david.haag@haagenterprises.com

 

[ornerynorsk]

The frictional characteristics of the bulk material will have a huge impact on your calcs. Imagine gravel vs polyethylene pellets. Applying vibration to the plate will aid in the material flowing to allow discplacement.

 

[limey1]

Another consideration may be to have a chamfer or leading edge on the vertical plate.