lifting platform: static analysis

[Ing Italy]

I have already done the analysis with the principle of virtual works and to practice I wanted to do it also graphically, but possible that graphically it is not possible to do? the members 5-1-2 have all 3 forces but do not seem to me solve it.Also I am blessed principle of virtual works is from two years to is part that I can apply it but energeticly I have not yet well understood what it means: when it says virtual work of the active forces null . Where did you get that energy from? I have a little confusion about the deep meaning of the principle, since unfortunately no one has ever explained it to me well. hello to all and thanks to those who want to suggest some point from which to learn!

 

[meccanicamg]

I'm out of office and I'm supposed to be back tomorrow. The pantograph lift has already been treated and solved staticly according to the normal rules of construction, total rigid body analysis and small pieces.

 

[meccanicamg]

in your schematics lacks the internal force of the hydraulic cylinder that keeps the system in place turning it into a rigid body. You do a search and you will find the pantograph lift I told you and there are the schemes with the forces. but what do you want to find with plv? the equation of the system? The forces? the couple needed to keep the system in balance? all is in the as schematics, just solve everything with the standard method adopted for beams and calculate the uncognized force that balances everything. attention to the fixing system of the cylinder, effective arm.

 

[meccanicamg]

Moreover on the net there is this beautiful pdf that at work we have found

 

[Ing Italy]

Thank you for your answers! .the f force is the one that keeps the system in balance, so it simulates the force exercised by a hydraulic-actuator cylinder for the cyber-lifting of the platform....the plv I used it to get me precisely the f force in function of the speeds of d and a (speed of translation platform) and it comes to me...but as I said in the graphic case I find 3 problems of the 3 forces where I can not solve that of the curved