Learning Forum

[oumaimalahmar.ol]

I wanted to make a simulation on a lifting tool that will lift a propeller, we're not going to model the part lifted from the blow, we need to know its center of gravity to apply a remote force. 

could you help me how I make this calculation.

find here my 3D geometry.

[peteroznewman]

nTo get the CG of an assembly, open Workbench and use a Mechanical Model component. In Engineering Data, add all materials used in the assembly and make sure each density is correct. Open the Model and assign the materials to the different parts. Then click on the top level component and in the Details window are the properties of the geometry: the volume, mass and Centroid X, Y, Z coordinates.n

[oumaimalahmar.ol]

thank you for your answer, the problem I didn't know where I'm going to apply my force, I wanted to know what my tool (lifting) will support the part that will lift, well I drew the part too but I wanted to know where I'm going to put the weight of this part? where I'm going to put the load? I have no idea.nknowing that the weight he can lift the tool is 50kg and the weight of the piece is 54kg.nthank yonn

[peteroznewman]

nIf you assume the yellow propeller is hanging from a single point, then the CG will be directly below that point due to the force of gravity.nI recommend you create a rectangular body at the thickness of the propeller and put that in the clamp, it just needs to cover the pad in the clamp.nApply downward force on the bottom face of that rectangular body equal to the weight of the propeller.nThe proper model would have frictional contact between the rectangular body and the pad on one side and the clamp foot on the other. For your first attempt, it is simpler to use bonded contact instead.nYou haven't said what holds this clamp to the bench. Those surfaces have to be supported. If the clamp body has a few holes that have bolts that secure the clamp body to the bench, you can make those hole faces Fixed Supports for a simple model. nI expect the most stress will come from the clamping force. Do you know how much the clamping force is?nAdd a Bolt Pretension load to the cylindrical face between the clamp body and the clamp foot. The convention is that a tensile force is positive, so you would use a negative number to get a compressive clamp load.n

[oumaimalahmar.ol]

thank you for your answer, you made things clear to me.nNormally the clamp is lifted by a strip I show you a picture of the reality, there are holes on the clamp but I have simplified the geometry as much as possible.nConcerning the clamping force I have no idea.nThank you very much.n

[peteroznewman]

nThank you for the photo.nSplit the face where the strap wraps around the edge. Use a Remote Displacement on that face and set all six DOF to 0, but set the behavior to Deformable.nThe minimum clamping force depends on the coefficient of friction between the propeller and the clamp pad and foot. If you assume the COF is 0.3 then the clamping force F must be W/0.3 where W is the weight of the propeller. It is likely to be 2 - 10 times more than that.n

[oumaimalahmar.ol]

Thank you for your answer n I don't know how I split the face, and are you talking about the upper surface the clamp?nthank youn

[peteroznewman]

nIn SpaceClaim, on the Design tab, there is Split, and Split Body. Create a Plane and use the Move tool to put one plane along one edge of the strap in the photo and another plane on the other edge of the strap, Click the Split button, select the face and then select the plane.n

[oumaimalahmar.ol]

excuse medo I need to know the length and width of the strip? because I didn't quite understand.nthnak youn

[peteroznewman]

nYes, the width of the strap. Put the plane through the clamp at each edge of the width of the strap.n

[oumaimalahmar.ol]

thank you so much i will do it.n