Clamping

Hello,

I am trying to apply some clamping (compressive) load in the analysis. My simplified model is below;

I have a top and btm shell element connected via a 1D beam (circular cross-section). my goal is that the 1D beam element compresses in the direction of the beam. How can I do that in patran?

Either I can define a compressive load or set distance for this beam to shrink. Let me know if there is a way to do it

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0 Sanjay Patel over 5 years ago

Hi Shaheer,

Bolt preload capability will allow you to do this. Following may be place to start.

https://simcompanion.mscsoftware.com/infocenter/index?page=content&id=KB8020326&actp=search&viewlocale=en_US&searchid=1568330910890

Thanks,

Sanjay.
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0 shaheer.iqbal over 5 years ago

Hello,

I constructed a simple model ( 2 hex cubes, 1 unit apart). I connected them via 1D element (CBEAM). Each end of the beam is connected to RBE2, where the independent node (center node) is connected to 1D element and the dependent nodes are connected to the surface nodes on the cube.

I applied a simple nodal force on one end of the Beam, I anticipated that the output of the beam force (axial) should be same as to my applied node. However, this is not the case . Almost 95% of the force is in the MPC while only 5 % is displaying in the beam.

Any reason why would this be happening? My beam is connected to the center node of RBE2 (thus it should be independent and free to move with any resistance)
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0 shaheer.iqbal over 5 years ago

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0 shaheer.iqbal over 5 years ago

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0 shaheer.iqbal over 5 years ago

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0 Arthur Hickson over 5 years ago

Hi, Sharing the complete input test model file that you ran may enable others to easily do the same and maybe provide advice based on fact and not conjecture.
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0 shaheer.iqbal over 5 years ago

Attached Files (1)

new.bdf.zip
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0 shaheer.iqbal over 5 years ago

Attached are the bdf and .f06 files

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new.f06.zip
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0 Arthur Hickson over 5 years ago

Hi ,

The node the load is applied to is connected by rbe2 to a 1x1cube that is grounded and to a beam that has a round section of radius .1 and is .6 long , which is in turn connected by rbe2 to another 1x1 cube that is grounded.

When the node with the force applied to it moves it puts the first cube in tension and the beam and second cube into compression. The applied force is reacted by forces in the first cube(via rbe2) and forces in the beam. The relative stiffness of the cube and beam is 1(cube) to 0.05 (beam, or .048 beam+2nd cube) so to a first approximation the cube will react 95% of the load and the beam 5%. This is in agreement with the observed force distribution.
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