Hoisting Boundary Conditions

[Naffoussi]

Dear all,

can someone explain to me how to apply boundary conditions under a hositing load case with 4 lifting points...?? and why ??

Best regards.

 

[rb1957]

? please clarify ...

have you modelled something you're lifting (a pallet ?) which will be suspended at four points and you're unsure about the constraints for this ??

Quando Omni Flunkus Moritati

 

[Naffoussi]

Hi,

Yes, In fact i am working on a dolly structure which will be effectively suspended at its four lifting points and i apply 1.1g in the vertical direction... I already worked on a three points lifting case but not with four.

Should i use a Cylindrical Coordinate system and fix one point in (XYZ), and the three others in Z (assuming that Z is the vertical axis)?

 

[rb1957]

i'd use rectangular co-ord system (or whatever you used to make the model ... you don't need a special co-ord system for constraints).

1) constrain Z at the four points (this resolves 3 equilibrium equations, yes?)

2) constrain X and Y at one point (this resolves 2 more) ... this is what you suggested by fixing one point

you also need one more, either ...
a) constrain X at a point offset in Y from 2), or
b) constrain Y at a point offset in X from 2).

clear as mud ?

Quando Omni Flunkus Moritati

 

[Naffoussi]

hi,

i will try this and keep you in touch

thank you