JCReynolds79
Automotive
- Sep 6, 2007
- 115
Hi all,
I want to simply determine total force on a very basic crank/piston assembly.
I have set up a simple assembly where the crank is just some datum axes (crank axis and an offset pin axis), the rod is just two fixed points (centre of big end and pin) and the piston is a sphere of known mass.
I can assemble these so that I can run a mechanism analysis to make them rotate as a crank assembly should, i.e. the piston mass goes up and down.
On paper, I could work out the resulting force on the system as basically mrw^2.cos(theta)+(r/l)mrw^2.cos(2*theta)
but how to get the same results from the mechanism?
I have played a little with connection reactions but I am guessing a bit now. If I put a connection reaction on my crank axis, it does not compute any results. I wonder if it is because there is no physical mass connecting crank/rod/piston?
I will attach an image.
Thanks in advance.
Regards,
Jon Reynolds
I want to simply determine total force on a very basic crank/piston assembly.
I have set up a simple assembly where the crank is just some datum axes (crank axis and an offset pin axis), the rod is just two fixed points (centre of big end and pin) and the piston is a sphere of known mass.
I can assemble these so that I can run a mechanism analysis to make them rotate as a crank assembly should, i.e. the piston mass goes up and down.
On paper, I could work out the resulting force on the system as basically mrw^2.cos(theta)+(r/l)mrw^2.cos(2*theta)
but how to get the same results from the mechanism?
I have played a little with connection reactions but I am guessing a bit now. If I put a connection reaction on my crank axis, it does not compute any results. I wonder if it is because there is no physical mass connecting crank/rod/piston?
I will attach an image.
Thanks in advance.
Regards,
Jon Reynolds