dynamic analysis 1

[68vette]

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?

 

[DonLeffingwellPE]

Figure out the tip vs. sliding forces.<br><br>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. <br><br>The horizontal force due to bar?&nbsp;&nbsp;Set = to f<br><br>Tipping force: Sum of the moments.<br><br>M(gravity) = Weight* (tipping point to C.G.) If package is uniform density<br>Mg = 7 * W<br><br>M(tipping) = f*Height of Bar<br><br>Make mu big enough so that the box tips.<br><br>Don Leffingwell<br><A HREF="mailto:dleffingwell@snet.net">dleffingwell@snet.net</A><br>(My last class in Statics was 30 years ago.)<br>I don't think you need to go into a dynamics analysis.

 

[appliedfem]

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