# Thread: Impact Forces on Chute

1. Bruce Higgins Guest

## impact forces on chute

I have a problem where 50t trucks dump run of mine gypsum into a chute. Gradation is up to 1.2m size rocks, and the total fall from truck box to chute will be approx. 5m. I am looking for some guidelines and/or publications as to the significant impact forces on the chute, which could be determined from the many variables such as rock size and physical properties, truck and chute geometry, etc.

2. Peter Brown Guest
I think this problem while appearing to be simple is actually more complex. I recently came across a discussion along similar lines in another discussion forum. The link is given below.

Regards (and good luck)

3. Discrete Element Modeling (DEM) can solve the problem. Define the particle shape you wish. Give it necessary material properties. Orient it to the height above the strike surface. Orient the plane of the strike surface. Drop it. THe rock or particle can be broken if its surface energy is in the breakage range.

Flow of granular materials can be modeled in many applications. To see a few, view our wbsite:
www.conveyor-dynamics.com

Lawrence Nordell
Conveyor Dynamics, Inc.

4. ## Forces n chutes

Perhaps you should examine the prospect of forming a wear box, or series of deflector piles, so that these large lumps can be deflected by impacting on previously retained 'smalls'. If space permits, a cascade repose system might be achieved that will absorb much of the kinetic energy of the fall.

Lyn Bates

5. Bruce Higgins Guest

## Re : use of "wear box"

Thanks for the suggestion. This arrangement no doubt would be very effective in dissipating energy but was discounted because the rock is gypsum. When wet, it can cake readily and form slopes about 10 to 15 degrees from vertical, which is a major operating problem.

6. Bruce,

Larry again. It now seems you are looking into a solution of flow mechanics in a chute design. I last sent a web location and references to a few papers (some below) noting the tools to provide an answer to your question.

4 Kruse, D. J. Conveyor Belt Transfer Chute Modeling and Other Applications Using The Discrete Element Method in the Material Handling Industry Bulk Material Handling, by Conveyor Belt III SME Publication 2000

1 L. K. Nordell and A. V. Potapov Comminution Simulation Using Discrete Element Method (DEM) Approach - From Single Particle Breakage to Full-Scale SAG Mill Operation SAG Annual Convention, Vancouver, BC September-October, 2001

4 J. A. Herbst and L. K. Nordell Optimization of the Design and SAG Mill Internals Using High Fidelity Simulation SAG Annual Convention, Vancouver, BC September-October, 2001

10 Nordell, L. K. Particle Flow Modeling: Transfer Chutes and Other Applications BELTCON 9 Conference, Republic of South Africa October 1997

You can take the next step and design the chute including impact resilience features to absorb the impact without substantial breakage to the gypsum. Furthermore, the model can handle rheology and your notation on sticky, Bingham like materials. All types of materials, material discharge, and their containment methods can be modeled.

Not sure if you seek a solution to finding the impact force or the chute design.

Lawrence Nordell
Conveyor Dynamics, Inc.
www.conveyor-dynamics.com

7. ## Impact Forces

For a basic start go to www.cemanet.org and look for CEMA standard 575-2000 Impact Beds/Cradles