Finding forces in a wall of a trailer box filled with mass

[Silentnox]

Trying to calculate the forces against the wall of a trailer and not sure how to do that in the case of it being filled with grain. Any help would be appreciated. I know the weight and volume and the wall profile just not sure how to find the force acting straight out against the wall. The grain is just piled in there and the trailer is open.

Thanks for the help in advance,

-Jason

 

[vonlueke]

In an example problem (wall aspect ratio of 4), using your sheet thickness (t = 2.657 mm), w in my previous post turned out to be too high and should instead be w = 0.116*(1-mu)*rho*a*h^2, where I assumed mu = 0.30 for a solid substance or mu = 0 for water. So that covers the middle rib midspan stress (for this particular sheet thickness).

However, I found that the maximum stress occurs at the midpoint of the bottom edge of the wall, which (in my example problem) turned out to be sigma1 = 0.0830*(1-mu)*rho*a*(h^3)/(t^2).

(Note that both of these results are fairly specific to only the stated sheet thickness, t = 2.657 mm, and probably wouldn't extrapolate to greatly different values of sheet thickness.)

Even though (1-mu)*rho could be refined to obtain a more accurate pressure distribution, what we can get out of this is, the maximum stress occurs at the midpoint of the bottom edge and can be fairly high because it's just a thin sheet there, in the vertical direction, under a relatively high bending moment about the bottom edge.

 

[vonlueke]

My above posts assume the wall bottom edge is clamped, which corresponds to the wall bottom edge being attached to something relatively very stiff. If I instead assume the wall bottom edge is simply supported, then in my example problem, sigma1 decreased to a very low value, w increased to w = 0.124*(1-mu)*rho*a*h^2, and the midspan stress on the lower trapezoidal rib became the maximum stress, which (in my example problem) turned out to be sigma2 = 0.0530*(1-mu)*rho*a*(h^3)/(t^2).

(As mentioned before, these results are fairly specific to only the stated sheet thickness, t = 2.657 mm.)