bjason
Mechanical
- Sep 14, 2012
- 6
Hi
I have a cutter assembly for a shredder which im trying to get the shaft loads for bearing and bending stress.
Its a 3 shaft machine and when all 3 shafts are turning there is a combination of loading happening. I can get the 3 shafts to simulate what looks like correct deflection but when i check the reaction force from one shaft to another against my hand calc the simulation values are lower than expected. So i went back to basics and simplified the simulation setup to just one shaft with torque so i could play with the fixtures and restraint to see if i was setup wrong but nothing gets close.
File attached
"shaft 4" has 2400000 lb/in driving "cutter upper 3" against "cutter stop lower 1" (just a dummy part to transfer load to shaft 1).
I calc that the force applied to "cutter stop lower 1" is torque divided by radius of "cutter upper 3" 2400000/16.25 = 147000 lbs
simulation shows 52900 lbs in expected angle.?????
I've tried splitting face on "cutter stop lower 1" and fixing it to get reaction force. tried not restraining shaft 1 and looking at free body forces but no joy.
What do you see im missing here?
I have a cutter assembly for a shredder which im trying to get the shaft loads for bearing and bending stress.
Its a 3 shaft machine and when all 3 shafts are turning there is a combination of loading happening. I can get the 3 shafts to simulate what looks like correct deflection but when i check the reaction force from one shaft to another against my hand calc the simulation values are lower than expected. So i went back to basics and simplified the simulation setup to just one shaft with torque so i could play with the fixtures and restraint to see if i was setup wrong but nothing gets close.
File attached
"shaft 4" has 2400000 lb/in driving "cutter upper 3" against "cutter stop lower 1" (just a dummy part to transfer load to shaft 1).
I calc that the force applied to "cutter stop lower 1" is torque divided by radius of "cutter upper 3" 2400000/16.25 = 147000 lbs
simulation shows 52900 lbs in expected angle.?????
I've tried splitting face on "cutter stop lower 1" and fixing it to get reaction force. tried not restraining shaft 1 and looking at free body forces but no joy.
What do you see im missing here?