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dynamic analysis

dynamic analysis

dynamic analysis

(OP)
I have been away from static and dynamic analysis too long. I would like to know how to determine the coefficient of friction value for the following problem. I have a box 24" tall x 20" deep and 14" wide traveling on a conveyor at 18"/sec. IF a bar is placed at the top of the box as to knock it down. What coefficient of friction belt do I need to prevent the box from slipping on the belt?

RE: dynamic analysis

Figure out the tip vs. sliding forces.

Find the center of gravity and the weight of the package. This gives you the normal force N. Horizontal force due to friction f= mu*N.

The horizontal force due to bar?  Set = to f

Tipping force: Sum of the moments.

M(gravity) = Weight* (tipping point to C.G.) If package is uniform density
Mg = 7 * W

M(tipping) = f*Height of Bar

Make mu big enough so that the box tips.

Don Leffingwell
dleffingwell@snet.net
(My last class in Statics was 30 years ago.)
I don't think you need to go into a dynamics analysis.

RE: dynamic analysis

dear,
the question posed by u is quite straight.
there r three forces,
1-friction force (at base of box)=nu*weight of box;
2-force due to acceleration of box(at C.G. of box)=mass of box *acceleration of motion;
3-force of bar ment for topling the box;
now if u balance these three moments u will get the value of force just sufficient to topple the box.

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