non linear analysis of thin plated steel structures 5

[executives]

Is anyone familiar with software that can do non linear analysis of thin plated steel structures?

 

[jakeline6]

Most general purpose FEA programs with decent nonlinear can do this. ABAQUS, ANSYS, NEiNastran to name a few. I would talk to them about your specific application and have them run a model similar to your specific problem.

 

[rb1957]

will NL codes handle buckling of skins under shear and compression loading (diagonal tension) ?

 

[jte]

Any good FEA code should handle any combinatin of loads in any directions. That's just part of what makes the FE method so powerful. Both linear and nonlinear codes should be able to deal with buckling...

jt

 

[rb1957]

jte,

i'm pretty sure that linear FE doesn't handle shear buckling of panels ... it's not a problem of applying the loads, but a problem that the stiffness of the structure and the loadpaths in the structure change as the panel buckles.

 

[jakeline6]

I think FEA will do shear buckling. I have seen it on the noran website multimedia library. I have also seen other FEA do it.

 

[jte]

I think the difference is in what kind of answer you're looking for: A linear FE should be able to give you the load to first buckling; a nonlinear FE has a hope of giving you that cool "mashed soda can" deformed shape and the load to get it there. Recognizing that we each live in different worlds, in my world for the most part first buckling is considered failure and determining where the wrinkles will be is neat but does not add value. Although there are a few cases where nonlinear buckling (creep-buckling) is useful to my industry.

jt

 

[GregLocock]

I've never used it but am familiar with the results from LS-DYNA, which we use for simulating car crash results.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[051174]

For analysis of thin plate the best thing is to perform by nastran the sol105 to reach first buckling mode and then sol106 by large displacement and no follower force so to define using non linear geometrical analysis the behaviour of your structure and the maximum load for investigation.The tendency is follow the thin plate behaviour.If a maximum in the load deflection curve is reached and a negative factor diagonal in the stiffness matrix is encountered this indicates that a buckling point is reached. Thereafter, the structure continues to deform in the post-buckling branch. In general beeing the processing time honerous i suggest to request in sol 106 only displacement. (NASTRAN is familiar to me) .

 

[jakeline6]

NASTRAN SOL 106 is what I use and it does handle post buckling and shear buckling. If you run SOL 105 you get the linear buckling solution which assumes small displacements and no follower forces. It is useful for getting the initial shape at the point of bifurcation. SOL 106 will also do this and is set up to automatically handle the bifurcation and post buckling response.

The question is what software will handle nonlinear analysis of thin plates. What is thin? 0.06 inches or 0.01 inches? Is it foil? For very thin structures and nonlinear analysis I have had sucess with ABAQUS and NEiNastran.

 

[fkmeyers]

We routinely use Nastran solution 106 for this type of analysis. The results often compare well to actual test results. Shear buckling should not be an issue with this solution sequence.

 

[eduardotano]

NL FE Software can give you good results (Nastran SOL106). To obtain safe results, you have to analyze the kind of post-critical behaviour of the structure (stable or unstable). Non-planar shells may be unstable. In these cases, the nature and/or magnitude of the imperfection you have to introduce to induce the “buckling” (geometrical imperfections or perturbation loads) affect the load-deformation path and the maximum (“critical”) load. The software generally will not be able to do this work for you. Be careful and check your models with bibliography examples.