cement bag

[mishra27]

have any one modeled a cement bag in a dyan analysis or any other analysis. What I am trying to do here is to drop a cement bag on floor and see the stresses of the floor.

 

[jheidt2543]

This is just an aside to your question. One of the great things about these forums is the variety of questions asked and problems people are trying to solve.

Why a cement bag? Are you interested in the reaction of the floor? If so, why cement at 94 lbs/bag rather than say corn at 100 lbs/bag? Or, are you designing the cement bag and want to see if it fails in the drop? If so, how far does it fall and why that height?

 

[mishra27]

jheidt2543, I am desiging a load floor of an automative vehicle, the cement bag is specified as spec, and the height from which it is dropped is also a spec, based on the observation of usuage of load floor. I am not intrested in the cement bag, however I cannot use corn bag as both of them will react differently to the stucture.

 

[cb1990]

Hi mishra,

A good place to start is with a static analysis of the floor with 2X the load to make sure the floor thick enough to hand the load without permanent deformation. Then move to Dyna. But I question the use of Dyna if you are not interested in the crush of the floor. If you are interested in the crush then there is much more to be said on setting up this analysis.

 

[DickButkus]

You could model the cement bag as a a bunch of solid elements using a material model appropriate for soils, then you can coat the lump with membrane elements. If you need to model the air, then use hydrostatic fluid elements above the cement powder.

I think I would start by just using a single 20 node brick to model the bag with the right mass, with simple elasticity, damping, and yield. If your not interested in the bag, but just it's effect, I would probably go this route, but that's just me. I tend to be very stingy with elements.

 

[JKEngineer]

I would expect that the properties of the material in the bag would be a major role player in the behavior of the bag and floor at the time of impact. As an extreme example consider the difference in what happens if a bag full of water is dropped vs a bag full of sand, vs rocks, vs a single large chunk of steel or concrete. Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering

http://www.KleinfeldTechnical.com