How can I correct this setup in Abaqus to run a solution for local buckling?

18 August 2015 3 7K Report

Hey all, here's the deets.

I'm using an L beam depicted in the first picture, with t/b at 0.01, 0.02, 0.03, 0.04 and the other dimensions as shown, poisson at 0.35.

Here's the steps I took in abaqus:

Import the ACIS part from solidworks (scale to 0.001 on import to convert mm to m)

Assign the section and material (74.5E9 for Young's, 0.35 poisson)

Add a "Linear Perturbation - Buckling" step

Add two reference points at the centroid of the part, at opposite ends, based on the location given in the excel file

Set up a "Constraint - Coupling", kinematic type with U1 U2 U3 and UR1 UR2 UR3 constrained for both reference points

Set BC on one reference point at the "Initial Step" to U1 U2 U3

Set BC on the other reference point at the "Initial Step" to U2 U3 (beam is laying on the X axis)

Add a "Load - Concentrated Force" equal to "-1" on the CF1 dimension on the "Buckle" step with the point load applied to the Reference Point and the loaded end

Mesh the part in the assembly level

Run the job

At this point, the solution I obtain in abaqus has been 20% below the book values, or more. This can be seen in the excel file.

I need to confirm that the way I'm setting up the model corresponds with the real world, so that I can proceed with my research knowing that my control setup is accurate, as I will be using orthotropic instead of isotropic materials.

Any ideas on what I could be doing wrong? I'm including both the excel file that has information on the control results, and the .SAT files I used to create the models in Abaqus. I attempted to upload the .CAE or the .ODB files, but no luck on ResearchGate.

Help please!

Ronen Yudzinsky

Sorry, forgot this image.

Pinaki Bhattacharya

Hi Ronen,

A few questions:

- what physical situation are you trying to model with the kinematic coupling constraint?

- did you request a reasonable number of eigenvalues?

- what do see in your message/data files (.msg, .dat)? have any of the eigenmodes been computed?

Kind regards

Pinaki

EDIT:: I updated my question to better reflect where I am now, and what I am seeking to find out.

> I'm trying to simplify the loading condition on the beam, by applying boundary conditions to the Reference Point and thus only having to swap out the Constraint settings when I import a new model.

>I requested 10, though I only need the first.

>I don't seem to get any ominous messages, aside from a warning about double-constraining nodes, which I specifically avoided doing (because I'm utilizing reference points)

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