#23 ABAQUS Tutorial: Modeling Geometric Imperfections With Buckling Modes

[@laraditzel]

Thanks for the class! Just to find some things faster... a detailed breakdown of the modelling process: 3:41 Rename Model 3:56 Create a Part and its Partition 5:14 Properties 5:36 Create a Section and Assign Section 5:57 Assembly 6:07 Create a Loading Step (NL Geometry) 6:50 Define Reference Points and Rigid Body Constraints 7:38 Create Reference Point to impose Rigid Body Displacement 8:26 Create Step: Fixed End BC 8:55 Create Step: Displacement (Ramp) 9:50 Meshing 10:18 to run the job? Define imperfections... [in progress...]

[@aneecafarzana8487]

Thank you so very much..helped me a lot to clarify too many confusions...may Allah award you with better requitals

[@avandinovena5920]

Thank you for the explanation Dr. Ahmed Elkady.

[@esmaeilmorshedi3573]

Like always perfect, Ahmed. Thank you

[@bishalnaik798]

Thank you Dr. Ahmed for the video. But can we include more than one files into Imperfection keyword?

[@AElkady]

I don't believe you can do that.

[@AbdulR-MannanB-]

Do you have a semi-circular load displacement analysis ?

[@CuongNguyen-tt4jp]

An useful video! How can we run a job with * imperfection and predefined fields: initial state in abaqus? Regards,

[@AElkady]

this video describs how to include and run a model with GI. For predefined fields (such as stresses) yiou can check this video kzbin.info/www/bejne/aqLcf42Na7R7gZI

[@SalahM07]

Slm Dr Ahmed could you clarify why the buckling load of the first mode is negative while the load is in y positive direction ?, i think the first mode should be positive with local buckling in the upper flange that's more rational with the direction of load

[@happylucas3033]

Hello Ahmed. Thanks for great pedagogical video. One question. If I have a column with several loads along it's height, or say a beam... Should I run Eigenvalue buckling analysis with all these loads and get the corresponding modes ?

[@BojanaHepp]

Ahmed, hope you are well. Do you maybe know if there is a way in Abaqus to find the eigenvalues within the specific component in the model? It is clear that the lowest eigenvalues are where the chance of buckling is bigger, but in this case I need to find that eigenvalue dedicated to one component.

[@debdeepmajumder9136]

Excellent videos on FEA... Hope you create similar videos for ANSYS APDL... with details on scripting.

[@hasanfal2515]

Why did we introduce the load (displacement 100 mm) into the main-model, and no effect was shown because of it?

[@neajacob8470]

Can u perform a buckling and post analysis in composite cylindrical shell

[@elenikoozbikila6771]

sir can you upload modeling of cold formed steel concrete composite beam please

[@CuongNguyen-tt4jp]

Dear Ahmed Elkady, if we have 2 steps in a job, the first step is a static, general analysis and the second is static, Riks. so how can we apply the imperfection for only the second step in this job? Thank you for your help!

[@sohinimishra9202]

Hello Dr. Ahmed, could you please clarify, what is the meaning of writing GLOBAL=NO, (after NODE FILE) in the edit keyword section of the linear buckling model? What will be the difference in result if I write, GLOBAL= YES?

[@AElkady]

GLOBAL=NO is specified to write vector-valued nodal variables (i.e., displacements is this case) in the local directions.

[@sohinimishra9202]

Thank you for your response.

[@sohinimishra9202]

Hello Dr. Ahmed, many thanks for making this useful video. I followed exactly the same steps shown here to model the initial geometric imperfection. However, I could not see the initial imperfection in the results of the main model at step 0. The .fil was also not created. However, the analysis ran successfully without any error. I am working with Abaqus teaching licence, for your information. Could provide any direction here? I am not very sure if this is any restriction with the teaching licence?

[@AElkady]

Yes, that probably means that your license does not support the "imperfection" keyword

[@sohinimishra9202]

Great! many thanks for your response.

[@miroamir1203]

thanck you doctor ,please doctor if I use pression load in my beam ,In buckling step I use "1 " us reference load ?

[@edgararturogomezmeisel2217]

Super good video!!!

[@محمدعبداللهزاده-ش3غ]

thank you for your good tutorial، I have a question. i'm working on IPE sections. my critical load in analysis , without imperfection is 42KN which is very close to experimental results. But when , I incloude the initial geometric imperfection equal to 3.6 mm which is 0.001 time of my beam length, i get results that is not true . its readuses to 32KN which is small than experimental critical load. and my second question is that , is it possible to eigenvalue to be less than my critical load? or it must be always , higher than critical load which obtain from nonelinear buckling analysis called riks method?

[@Hello-vu7hb]

Hey Ahmed, I am modelling an I section like you are in the tutorial, but the space between the flanges is filled with reinforced concrete: in this case: is it enough to conduct a buckling analysis only with the steel profile and create a fil file from only the steel beam or do i have to conduct a buckling analysis from the whole concrete filled i section? because in both cases the first mode is the same so if i scale it the same it shouldnt matter no?

[@AElkady]

You might get errors if the main model nodes are not consistent with those of the buckling model. ABAQUS documentation states the following: "ABAQUS imports imperfection data through the user node labels. ABAQUS does not check model compatibility between both analysis runs. Node set definitions in the original model and the model with the imperfection may be different. Care must be taken for models in which ABAQUS generates additional nodes (for example, the nodes generated for contact surfaces on 20-node brick elements). In such cases you have to ensure that the models for both analysis runs are identical and that the nodal information for the generated nodes is written to the results file"

[@Hello-vu7hb]

Thank you very much!