How to give a lifting load at 4 points to a structure in Static Simulation

[DeveshYadav]

I am designing a Structure {Structure contains a Container(20ftx8ftx8ft) sized body} which needs to be lifted at 4 corners via belt from a single hook on a crane. I have modeled cylinder bars on the structure at 4 corners. Now I need to check whether the structure will collapse or not when lifting. 

I am not able to model the constrains properly here. If i give fixed support at 4 corners, structure becomes stiff and stresses are less.Attaching a pic for better representation of what is needed.

I am able to Simulate Case 2. But need to simulate Case 1. Please help me in simulating Case 1.

[John_Holtz]

Hi @DeveshYadav

In order to do the simulation directly, you either need a local coordinate system so that the constraint only works in the direction of the cable, or you need beam or truss elements to model a section of the cable. Fusion has neither of those.

You can do it indirectly in Fusion by starting with your case 2. Fusion will calculate the vertical reaction force. You know that the vertical force is just one component of the tension in the cable, and you know the orientation of the cable. So you can calculate the total tension in the cable. Then in a second simulation, apply the two horizontal components of the cable tension while leaving the vertical constraints. This will give the compression forces that you are looking for. After the second analysis, you should confirm that the vertical reactions are still the same.

Let us know if you have any questions.

[dieselguy65]

looks like you are trying to pick up a shipping container.

i dont have simulation experience in fusion, but i have alot of experience picking up heavy things with cranes.

if that container is empty, you will break the lifting slings at those angles before ever buckling the container.

a rule in lifting, the sling can never be at a 45 degree or more angle between the load and lifting hook.

every degree it slopes, multiplies the stress on it.

[DeveshYadav]

Yes. The structure is similar in size to shipping container. The attached pic was representing the case to get better understanding. The angle is around 45 degrees between sling and horizontal.

I am designing my structure having lifting points towards center of length to increase the angle of sling to around 60 degrees.

[DeveshYadav]

I have modeled a plastic component which represents a sling. Its attached to structure as a bonded element. The cross-section of plastic(rope/sling) is very small around 10mm. The plastic fails but acts as a rope and puts compressive forces as reactions on the structure. As plastic is not a beam element, it will resist itself and not transfer full load on the structure, But this is closest I can do.

Let me know if there are better options/ways. I need to do many iterations to come up with a optimized structure.