Beam Modelling

[wozorio]

Dear all,

I'm a little confused about the beam modelling when using Abaqus.

I'm trying to create a simple point load model on a cantilever beam. Initially i created it 2D model (or 1D?). Set up BC and apply load at free end. (see attached)

http://files.engineering.com/getfile.aspx?folder=01bdcbbf-02b2-4e0b-8a73-1f42cf079861&file=2D.cae

I'm looking at end deflection height (mm) and comparing it to euler bernouli AND timoshenko. All of them do not seem to agree with each other. I was wondering what beam stiffness modelABAQUS uses. I've also done mesh study for convergence of result.

I'm then trying to simulate it using a 3D model. I tried using similar approach but the results are not agreeing. It seems i'm getting too much local deformation at the nodes where I apply the force. I've tied the nodes at the top edge as rigid node set and apply the force at the top edge at free end. Is there a better model to simulate the model of 2D(1D) as of above? The 3D model has not fully converged as computer cannot handle but it doesnt seem to converge near EB / timoshenko or the 1D model. Suggestions please.

http://files.engineering.com/getfile.aspx?folder=4cf1eefd-3a63-47c6-888d-b3a788f499d5&file=3D.cae

Much Appreciated.

W

 

[portliner]

The 2D beam deflects -1.543 at the tip. I have oriented the beam as: height=20 width=25. Remeshed with 2-order elements, only 20 elements biased towards the fixed end.

 

[wozorio]

yea. at 2D model
end load: 2000N, L=200mm, h=20mm, w=25mm, E=209E3 N/mm, v=0.3,

Abaqus: ~ -1.543
Euler-B: PL^3 / 3EI = -1.531
Timoshenko: EB + PLh^2 / 2GI = -1.591

EB < Abaqus < Timo

I thought Abaqus uses one of them and should therefore be much closer / the same.

any explainations to that?

 

[portliner]

mmm... you have not selected "transvers shear stiffness" in the "beam section". But the beam is very slender here so the shear stiffness would be neglible