Hello,
I made a simple model to try and understand the joint dimensionsfor friction in a coincident planar mate. It's left me moreconfused.
My model is just a .10 inch thick by 1.00 x 2.00 inch plate ofaluminum (density of .10 lbf/in^3 so total weight is .020 lbf). Iapplied a .001 lb force to the .10 x 2.00 inch face. Gravity set toload the 1.00 x 2.00 inch face. Initially I set the friction tozero and got perfect results for accelleration, velocity, anddisplacement (as compared to hand calculations).
When I set the friction coefficient to .025 (to give half theacceleration as the frictionless case) I got strange results.
With coincident mate friction dimensions set to L=1, W=2, and R =2the plate only moved about .050 inch and then stopped. I wouldexpect some
"tipping" of the plate to cause less than ideal case results, butwith the plate only being .10 thick this should not have had muchinfluence.
I ended up increasing L and W to several hundred times thier actualsize before getting reasonable results.
Can any body tell me what I am doing wrong?
How do L, W, and R relate to each other? Is L and W used (whileignoring R) for a rectangular surface (such as mine)? Is R used(while ignoring L and W) for a round surface?
Please help. This has really shaken my confidence in my ability toget useful results from any model.
SolidworksMotion Studies
I made a simple model to try and understand the joint dimensionsfor friction in a coincident planar mate. It's left me moreconfused.
My model is just a .10 inch thick by 1.00 x 2.00 inch plate ofaluminum (density of .10 lbf/in^3 so total weight is .020 lbf). Iapplied a .001 lb force to the .10 x 2.00 inch face. Gravity set toload the 1.00 x 2.00 inch face. Initially I set the friction tozero and got perfect results for accelleration, velocity, anddisplacement (as compared to hand calculations).
When I set the friction coefficient to .025 (to give half theacceleration as the frictionless case) I got strange results.
With coincident mate friction dimensions set to L=1, W=2, and R =2the plate only moved about .050 inch and then stopped. I wouldexpect some
"tipping" of the plate to cause less than ideal case results, butwith the plate only being .10 thick this should not have had muchinfluence.
I ended up increasing L and W to several hundred times thier actualsize before getting reasonable results.
Can any body tell me what I am doing wrong?
How do L, W, and R relate to each other? Is L and W used (whileignoring R) for a rectangular surface (such as mine)? Is R used(while ignoring L and W) for a round surface?
Please help. This has really shaken my confidence in my ability toget useful results from any model.
SolidworksMotion Studies
