#21 ABAQUS Tutorial: Defining Concrete Damage Plasticity Model + Failure and Element Deletion

[@TheEngineeringHub]

This channel is a gift to humanity! Thank you!

[@guoxinxin693]

I can't agree more! Thanks!

[@林一-g4i]

谢谢！Thank you for your tutorial.

[@hairocontreras3374]

Me gustaría decírtelo en inglés, o en tu lengua materna, pero lo diré en español la cual es mi lengua materna. Sinceramente eres unos de los pocos exponentes que he visto en internet que tiene la capacidad y la seguridad para enseñar estos conceptos y encima usando un software tan poderoso en FEM como es Abaqus. Desde la distancia te deseo lo mejor en tu vida profesional. Saludos desde Perú.

[@oussamaadd9196]

جزاكم الله خيرا دكتور أحمد على الشرح الوافي.

[@wacunjoroge1649]

Thank you for your tutorial.I was not understanding the CDP part but now I do.. Continue with the good work! Saving a lot of grad students 😊😊

[@bashirahmadrasheedy1081]

Thanks Sir for great lectures we are waiting for more videos.

[@woodrunner51]

These videos should be something we can reference in articles

[@woodrunner51]

It is often easier to solve problems, and learn the craft through your videos than through manuals etc...

[@rimiteshsingh3089]

Thank you Dr Ahmed Elkady, very informative video. However, i am conducting a experiment on slag concrete to test the strength behavior of the Concrete, hence i would like to request for information on how will go about defining the properties of the Slag Concrete in Abaqus.

[@3dmdavid]

Your presentation was awesome, thanks

[@nguyenanht.3066]

It is really clear and meaningful for all. Big thanks

[@saffanahnawsrah9035]

Thank you Dr Ahmed Elkady, very informative video.

[@omarnazar6820]

From all the videos I watched about Abaqus, your videos are the best and the most understood, can you please do a video on Prestress, also are you willing to give training? Looking forward to your answer Dr. Ahmed

[@magedqasem7403]

Great explanation Dr Ahmed. Thank you a lot

[@addislijalem9258]

You are exceptional !!! Really love Your Knowledge !!

[@yura13berlin]

Beautiful Explanation, Many Thanks

[@assefaerkocho8286]

thank you Dr. this basic and important information for Abaqus user!

[@eslamahmed7022]

Too informative I loved that I really enjoyed and learned a lot Dr Ahmed Thanks you god bless you

[@surendranmurugesan2511]

This is very elaborate and detailed. Great work

[@edinsonmunozhorna143]

Muchas gracias por compartir su conocimiento, desde Perú muchas bendiciones!!

[@MahmoudEmam-p3h]

جازاك الله خيرا و جعله في ميزان حسناتك ان شاء الله

[@adibyeg5296]

Thank you so much. It helped alot with understanding the CDP model.

[@一昂的菲特]

Thank you for sharing your knowledge. Thank you very much. I've learned a lot from your video series.

[@natethegreat4266]

Very helpful and very educational. Thanks.

[@mahinulislam7663]

Very very Helpful tutorial. Thank you sir for this .

[@taimoorshehzad8646]

Thanks Sir .. it helps me alot From 🇵🇰

[@tohiddastan9423]

Gooood Job Ahmed jan

[@thongnguyenvan6775]

Thank you for your explaination. It's so useful. Great lecture !

[@zainsaeed147]

Really impressive and clear understanding ,,while developing the sheet I got following queries 1- I already had the stress-strain data from the concrete cylinder using strain gauges. I saw in video that you actually used percentage strains. Is this just dividing the strain by 100 or some other conversions too 2- For the damage factor i dont get zero values initially if I subtract the ratio from 1. Also when I reach the yielding compressive strength of concrete my damage parameter is 0.54 ..is it ok 3- My plastic strain are coming negative do I need to put those values zero directly or there is some other mistake in the data 4- While entering data in ABAQUS for the tensile part we actually get the split tensile strength from cylinder and the rest of the softening branch wasnt obtained so we use models is literature for this part ??

[@farzanehabedini5723]

Thank you for this helpful tutorial.

[@AElkady]

The CDP material data used in this tutorial is available for download (see link in video description)

[@amrmasoud5580]

Hi Dr. Kady, Have you excel sheet compute the CDP directly?

[@fayizamin]

But sir its not the excel sheet kindly upload it in excel form

[@jjjjjjjjj4345]

Perfect as always❤

[@rubasleet]

Abaqus exited with an error. It says, "The independent variables must be arranged in ascending order." I think this was because of the forced zero input of the concrete damage (dc). Can you help me?? If It costs money for the question, I will pay for you, Dr. Ahmed.

[@miqdadkhan3267]

How to obtain stress strain curve from these data ?

[@quangmanhtruong8170]

Great video. Thank you so much!

[@lamiakamal1005]

thank you very much for this interesting information

[@amirhosseinie1026]

Very helpful. Thanks

[@Abdu408]

Thank you Prof. could you please make one video on the Reinforcement concrete-filled steel tube, and T joint in column and beam

[@shubhamjain8157]

Hello Sir, Very glad to see this informative video but I wanted to know how the temperature effect is incorporated into this model. I am also a structural engineer and do simulations. Basically, my area of research is the effect of composite columns at elevated temperatures. When I was taking the consideration of temperature in the damaged part of the CDP model it gives an error "Negative plasticity or crushing strain is more than plastic strain", I have checked that thing which is correct. Could you please guide me to deal with the CDP model considering temperature? Thanks & Regards.

[@mostafamoos5678]

Thanks very much really helpful video , sorry just want to ask a question at fire should I input those data at different temperature too ??

[@Pinky_Gaming123]

Dear Dr, can you add another topic regarding thermal effect to the compression and tension plasticity? Thank you

[@张浩然-n1w]

great video, thank you

[@fadoobabadpl]

Thank you very much!

[@haulehuynhquang6672]

It's great. Thank you so much.

[@PedramGhassemi-h4g]

Dr. Elkady, could you please explain how could you determine yield stress and the elastic modulus from the stress-strain curve of your concrete sample?

[@daifukumochi3686]

I'm wondering the same problem sir, have you figured it out yet sir?

[@AElkady]

E is dedcued as the secant stiffness based on the fc0/fcu ratio specified by the user. This ratio is 0.4 by default.

[@benmeloukaabdelkader737]

Thank you very much sir.

[@omeryavuzeski3979]

Thank you for your video Dr Elkady. Are the data you use in your video experimental tension data for tension behaviour? Thanks in advance.

[@aminegc9353]

thank you so much dr , please can you share with us the presentation please ?

[@felipebarbosa1280]

Fabulous!

[@ahmedziko7564]

great work, thanks

[@zahraaazubaidi1985]

What if I did not have the goining down part of the graph after the test??

[@AnnoyKumarGhosh]

First of all thank you sir for such wonderful video. I have one question: my abaqus file (modeling of beam-column joint under cyclic test) is showing error when i do edit keyword as suggested in this CDP video. For simulating crack do i need to install the exe. file in you CDP generator file as available in the link mentioned in the description. I am using Abaqus 2020. I will be grateful if you have any other suggestion to deal with it. Thank you sir

[@IrfanAli-p7o]

Dr. Ahmed can you please tell me how to define strain rate in CDP model in compression damage section?

[@zainsaeed147]

Dear Prof can you please confirm that for CDP in Abaqus the concrete stress- strain relationship we need to use is for a confined concrete or unconfined concrete ?? Actually i have a simulation in which the grout is confined by steel sleeve so i need to know that i modelled the sleeve in Abaqus and i believe that Abaqus should consider the confining effect of this steel sleeve on grout and therefore in my CDP i used the unconfined stress - strain relationship ..is my approach ok or i need to used the confined stress -strain relationship for my CDP ?

[@Shisui549]

thank you Sir

[@meazawu]

GOD BLESS YOU

[@lintapaul3108]

Sir Can u please make a video to model confined concrete in CDP

[@souviksaha3935]

Sir, could you please make a video on coupled temperature displacement analysis of RC structure?

[@mostafaabbasnejad489]

Hello. thank you very much for these valuable tutorial. I have a question please. I did experimental cylindrical compressive tests before and I want to find the plasticity parameters. can you please guide me how to determine them?

[@mogaz264]

جزاكم الله خير يادكتور. Is the elastic strain we substitute from the total strain is calculated as constant value? (max elastic strain at yield) or variable value calculated as ratio between stress and young's modulus for every stress value?

[@AElkady]

you can just use the yield strain at the initial yield point.

[@ghazialobaidi2218]

That is enough to run my case for blast load analysis of

[@structurelearninghub3340]

is it necessary to convert stress strain curve of eurocode into true stress strain curve ?

[@zhenghaozhang8609]

Hello Dr. Elkay, just a quick question about the element deletion. Is the element deletion only affecting the visualization? Or is it actually affecting the analysis result?

[@AElkady]

No, it would not affect the analysis. This is a visual representation of reaching the maximum value of the damage parameter D. classes.engineering.wustl.edu/2009/spring/mase5513/abaqus/docs/v6.6/books/usb/default.htm?startat=pt05ch19s02abm39.html

[@niteshshrestha6204]

Dear sir, can you make video on concrete smeared cracking on ABAQUS for non linear properties of concrete?

[@aasif.s.r6363]

Can you please do a video on punching shear in flat slab.. please help me

[@timosaksala4797]

30:40: "Abaqus considers complete failure of the constitutive material model when....". Do you mean the Abaqus CDP model itself fails to describe the actual behavior of concrete when degradation is 1? ;-)

[@abrahaleytewele1031]

hello, sir thank you so much for your supporting video here.I think the elastic modulus of the concrete is taken from the slope of stress -strain until yield stress which given us189.619 MPa(N/mm2) .but your result is 20111mpa how? even their digit has a different?

[@AElkady]

I think you mean 18961.9MPa not 189.619MPa...Anyway, here I'm using a slightly different value for Ec but it does not matter, you can used 18962MPa instead.

[@abrahaleytewele1031]

@@AElkady thank you sir for ur response ya it is 18962Mpa .

[@dbc5185]

I think that he calculated Young's modulus of 20111 MPa from tension data.

[@brwasaeed6477]

Thank you, DR Ahmed, it's a very nice tutorial and very useful. I just have a small issue with entering concrete failure. I got the error "Unknown keyword "concrete failure." The keyword may be misspelled, obsolete, or invalid. Could you please help me with this? "

[@mohitbisht8503]

Dear Sir How to incorporate large strains for element deletion in CDP model during large strain loading events simulations such as ballistic impact loading simulations?

[@rachit.23.93]

Thanks for the video. Sir, i just have one question that if i want to include dowel effects of rebar in RC structure; can i change the value of tension stiffness recovery to say 0.5 or 0.7 to model the behavior under dynamic loadings or i have to increase the values of cracking strain at failure (say 0.05 plastic strain in tension at failure). I have read the abaqus documentation but i just want to confirm with some scientific studies (maybe abaqus user conferenece papers) on this tension stiffness recovery parameter.

[@AElkady]

There are actually a number of good esearch papers going in depth regarding the proper modeling parameters to use in different cases (look up finite element reinforced concrete in google scholar). I recommend you check some of those as they would include more relevant answers.

[@omeryavuzeski3979]

Hi Dr. Ahmed Elkady. If we use displacement data for the tension part, how can we define the element deletion? Because you explain just for strain. Could you please explain? Thanks in advance.

[@AElkady]

I'm not sure I understand your question. Please re-phrase

[@omeryavuzeski3979]

Hi @@AElkady , In your video, you are using strain data. My question is if I use the displacement data for tension part, What will I do?

[@Grandpa_x_Shark]

sir, why is dc equal to 0. its supposed to be 1 at the starting strain cause its corresponding generated compressive stress = 0. so (1-0) = 1.

[@AElkady]

the dc parameter starts at 0 and reaches 1 at full degradation.

[@masoudghalejoughi5522]

Thanks. Could you please share a video about ductile damage and its definition procedure?

[@AElkady]

Will try to make a tutorial on this soon.

[@masoudghalejoughi5522]

@@AElkady Thanks

[@amrmasoud5580]

Hi Dr. Kady Thanks Please tell me how to Model Failure and Element Deletion for steel bars ? thanks

[@AElkady]

Will to try to make a tutorial on this soon.

[@semirmohammed8389]

Dr, What if we want to use ACI code in this tool?

[@anjankuinkel6844]

Dear Dr, Ahmed. If I want to determine damage parameters without any strain data and without experiment. How would I be able to do that?

[@AElkady]

kzbin.info/www/bejne/gJ6ckmOajsSEq5I

[@christopherosasona5125]

From the cracking and inelastic strain how to a change it to displacement value? I want to use displacement instead

[@AElkady]

multiply the strain values with the mesh element characterestic length.

[@emanseleman6563]

when i edit the keyword as video , it give me this error Unknown keyword "concretefailure". The keyword may be misspelled, obsolete, or invalid. i'm sure of writing so why ?

[@lamiakamal1005]

Thanks.

[@OSAMAWALI-ht4pp]

Hello Dr. When i try to do the data entry using the exact same code you provided, it says "syntax error" What should i do?

[@Ramey2015]

Hello Dr. Ahmed, do you have any tutorial about using subroutine specifically VDload? Or do you know any resources regarding using VDload. I tried to search but couldn’t find anything useful. Thank you in advance. جعلها الله بميزان حسناتكم

[@AElkady]

Unfortunatly, I don't have anything specific on VDload subroutine but this link should includes all the important info abaqus-docs.mit.edu/2017/English/SIMACAESUBRefMap/simasub-c-vdload.htm

[@Ramey2015]

@@AElkady thank you Dr. Ahmed.

[@Ramey2015]

@@AElkady I was able to understand the using of Dload and VDload and link them to ABAQUS. From the jobs, i can upload the VDload file, which is written in fortran language. My problem now is that I am running my model using different server and all what I have to do is to submit the input file by itself only, do you know from your experience how i can include this file in the input file rather than add it as an attachment??? Another question, how we can model moving load ( i.e. HL 93) using ABAQUS?? Thank you in advance

[@noora.khalaf7852]

Thanks.. have a video tutorial about RC under impact loading?

[@AElkady]

I will try to add one soon

[@diribamosisa6509]

Hello Dr. Ahmed I get more skill from your video tutorials! I try to model concrete steel encased composite frame joint of column-beam! and while I submit the job it say "DURING THE CONVERSION FROM CRACKING TO PLASTIC STRAIN Abaqus FOUND NEGATIVE AND/OR DECREASING VALUES OF PLASTIC STRAIN. VERIFY THAT THE DEGRADATION DATA UNDER *CONCRETE TENSION DAMAGE IS CORRECT Analysis Input File Processor exited with an error." please could you help me?

[@Ramey2015]

Thank you for the great explanation, I am working on RC in-span hinge model. First, I modeled the concrete with elastic behavior only, and the model run without any error. Then, I defined concrete damage plasticity following your explanation, but I got this error " Time increment required is less than the minimum specified". I decreased the min. of increment size, then I got this error" Too many attempts made for this increment". what should I do? thank you in advance.

[@AElkady]

I assume you are using a static step in your analysis. To avoid convergence issues, I recommend you use a dynamic explicit step when dealing with softening materials such as the CDP model. Please check the tutorials on RC beam bending and explicit solver.

[@Ramey2015]

@@AElkady thank you so much Dr. Ahmed

[@qusaiaborahmeh396]

Hi Dr , which expression you used here for concrete tension ??

[@AElkady]

I'm using Cornelissen et al. (1986). The data is available to download (see link in video description)

[@anandamitra5580]

Sir i am searching for CDP values for 80Mpa concrete. Please help sir.

[@hazratkhan1459]

Respected sir, I am doing Finite Element Analysis of Prestressed Girder using ABAQUS, could you please help me in this, or would like to make a video on this topic? Thanks in advance

[@mahinulislam7663]

Sir, Can I have the Reference Paper link, from where the datas are taken?

[@noora.khalaf7852]

Thanks

[@msc.str.engineermohammedad4269]

Please Dr.Ahmed, would you mind to tell me why my slab behaves like a rubber when I impact it by 3 Ton mass falling freely from 4 m height ? I am using CDP model

[@AElkady]

Not sure I understand what you mean by "behaves like rubber".Please clarify.

[@felipepiva6084]

When I have a monotonic loading, the use damage dc and dt is important? I have to lose stiffness on element?

[@AElkady]

They can be important in monotonic loading IF somehow there is reversal loading taking place in some of the model elements. If not, then dc and dt are irrelevant. In general, it is a good practice to define all aspects of the material model.

[@sohailhamza2812]

Hi how can I find the formulas behind the output results in abaqus?? To be specific I want to know formulas which the software uses to give the reaction forces..

[@AElkady]

I don't think I fully understand your question. The reactions are obtained from force equilibrium during the FEA procedure.

[@sohailhamza2812]

@@AElkady I want to know those equations which are already fed in the fea software.

[@flawlessflaw662]

hello can i have the tutorial slide please?

[@irdotcomid741]

Hallo Sir, Thankyou for the sharing. Can i request to download the file you shared on screen?

[@AElkady]

Please check the video description.

[@ridhosurahman8461]

Hello Sir. I have tried to use keyword 'concrete failure' in abaqus, but it gets error. The Abaqus said that this keyword is not recognised. Could you please let us know how to solve this problem?

[@AElkady]

This keywork is available in v2019 and later versions. If you are using an older version that might be the issue. Incuding "concrete failure" is not critical anyway and you can ignore it.

[@ridhosurahman8461]

@@AElkady Alright. Then I will update the software to the latest version. Thank you very much.

[@ephremmohammed2107]

how can I get the exact ultimate strain of concrete under compression?

[@AElkady]

You can obtain stress-strain data from an expirement or from available empirical models in litrature.

[@karthikbharadwaj1787]

how to get yeild stress and cracking strain data in case of no experimental data u have not explained

[@AElkady]

As discussed in the tutorial, there are a number of empirical models in litrature (see for instance, EC2 and Model Code (1990))

[@王琦-m6s]

Dear Dor,I used your data ,but still showed "DURING THE CONVERSION FROM CRACKING TO PLASTIC STRAIN Abaqus FOUND NEGATIVE AND/OR DECREASING VALUES OF PLASTIC STRAIN FOR MATERIAL NEW-CDP. VERIFY THAT THE DEGRADATION DATA UNDER *CONCRETE TENSION DAMAGE IS CORRECT". I need your help ,please!!!!!!

[@jeslinjose7023]

If you got the solution, please help

[@daifukumochi3686]

what's the relation of sigma c with f'c sir?

[@AElkady]

Please check the cited references in the video for the stress-strain formulas

[@mayureshsalunkhe3732]

Unknown keyword "concretefailure". The keyword may be misspelled, obsolete, or invalid. this error I got after typing this keyword.

[@karatelord3232]

please can anyone help I'm trying to run the analyze but I get this error message what should I do (Unknown keyword "concretefailure". The keyword may be misspelled, obsolete, or invalid.)

[@AElkady]

note that this keyword is available in post 2018 releases