# Projection of forces (Handling of an assembly)

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Hello,

Today, I am interested in the handling problem on an assembly consisting of a body and 4 parts serving as feet (on which the assembly rests during conventional use) all fixed to the body by 3 screws.

Handling for this assembly is carried out with a handling overhead crane, knowing that the assembly is lying on the side opposite to A to facilitate the handling.
There are 2 lifting shackles placed on 2 of the feet of the assembly (positioned on the through and smooth holes of the feet) and 2 slings of 1.5 meters are used to link the 2 shackles and the handling bridge. In addition, 1 other sling of 3 meters makes the link between the bridge and the other part of the sub-assembly, passing through one of the holes in the body and coming out through the other. Thus, during handling, the weight of the assembly (approximately 5 tons) stresses the feet and the upper part of the body where the 3-meter sling passes.

My problem is at the feet of the assembly, in fact I want to determine if there is a risk of breakage at the level of the smooth hole.

To solve this problem, I thought of 2 solutions :
--> Fully model the assembly using Ansys and replace the slings with spring elements of the same stiffness as the slings used
--> Only model 1 foot on Ansys and calculate the force (norm and direction) to be applied to the foot.

I am interested in the second solution so I am trying to determine by calculation the forces to be applied to the foot on Ansys.

Hypotheses :
--> The lifting shackles are not taken into account to simplify the calculations and I do not foresee a huge difference in strength with and without.
--> The weight applied for each foot is Total weight / 4.

Calculation of the forces to be applied on Ansys for the feet alone:

y = Angle between F and x
p = Angle between AO and z
The direction of the force F is the same as that of the sling.

Fx=F.cos(y)
OA=F.sin(y)
Fy=OA.sin(p)
Fz=OA.cos(p)

Sum of forces on z:
Fz=Weight of the assembly/ 4
OA.cos(p)=Weight of the assembly/ 4
F.sin(y).cos(p)=Weight of the assembly/ 4
F=(Weight of set / 4)/(sin(y).cos(p))

I determined the angles y and p with my CAO model but I am not convinced by my determination of the force F according to the known force, i.e. the weight of the assembly.

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