A place FOR CAD users BY CAD users
https://cadforum.net/
I'm not understanding what you are looking for. What do you mean by 'maximum', 'minimum', & 'middle'? Have you done your hand calculations yet? That is the first place to start in order to see what the static forces would be in any given orientation. Add a kinematic analysis (again, hand calculations are probably all that is necessary) to understand the forces during motion.
What you are describing is usually due to position if you are lifting/moving a 'fixed' weight. This is merely a result of 2D static forces based on the geometry of the system. Usually one wouldn't even apply FEA in these situations since hand calculations are normally sufficient. Lay the system out in 2D, determine the force required at the start of the sweep, half-way through, and near full extension. Aside from the fact that the 'mid point' may not be the most interesting position for determining the forces, this process will get you very close. If you end up wanting to do an FEA anyway, this will give you a sense of what you should end up seeing for results.Assis As wrote: ↑Thu Jun 10, 2021 3:47 am thank you for reply
i mean that compression and extension force of hydraulic cylinder , in general hydraulic force increase while lifting , so there is maximum force that is required and when lifter move down there is force by hydraulic cylinder too , middle force that is between maximum and minimum forces ,
like
Max=1,6N
Min=1N
Middle=1.3
something like this
this all depends on whether you're attempting to calculate force the cylinder can create or whether you're trying to calculate how much force you need in the cylinder to cause movement. These are two different calculations.
That's what I was attempting to explain. However I get the impression that the OP is more of a draftsman than an engineer.MJuric wrote: ↑Thu Jun 10, 2021 8:35 am this all depends on whether you're attempting to calculate force the cylinder can create or whether you're trying to calculate how much force you need in the cylinder to cause movement. These are two different calculations.
Calculating how much force a cylinder puts out is a simple hand calc of force * area. If you want to get closer you have to account for things like friction, side loading, flow rates, back pressures and on and on etc etc. but most of the time, at least in air and hydraulic systems, you just oversize a bit.
On the other hand calculating how much force you need is an entirely different calculation and has nothing to do with the cylinder but is a function of the system the cylinder is in. Once you know maximum force needed thru the entire travel of the cylinder you just size the cylinder to that force. Unless you're sizing a system where force and flow are critical at various travels of the cylinder you typically don't care if you have more force than you need.