Hi all,

First post so bare with me!

Part of my university course requires me to conduct a multi body analysis on a component i'm designing to fully fulfil my grade.

To do this, I'm trying to verify my hand calculations for motor torque and power on a rock drilling carriage. The carriage consists of two sprockets which support a duplex chain, with a motor connected to the first sprocket, the drill carriage seat is attached to the chain, as the chain moves the seat traverses along the carriage (two PFC beams).

I've simplified the model so it's just the beams, the seat and the first sprocket. I've set up the limit mates for the carriage linear travel, and I've set a rack and pinion mate between the sprocket and the seat; so as the sprocket spins the carriage moves - nice one.

I can then add the motor in the motion analysis and get it to work as it should. My problem starts when i come to measure these forces, the torque at the motor is reading a maximum 69238910N/m....my hand calcs say it should be 1500N/m...lol.

What am i doing wrong here? Because obviously that number is ridiculously high? I've tried setting contact mates between the seat and the beams so that they both 'Greasy Steal', and i've made sure that there is clearance between the seat and the beams.

I've attached the problem file, and any help is greatly appreciated; deadlines in 4 weeks or so...i'm currently ahead of the curve, but for how long!

Thanks,

Connor.