What a brilliant series... The most complex things were dealt with an ease... Such a great learning experience... Request you to have more lectures on storage bins with materials under seismic action or fluid with hydrodynamic actions...
Hello Sir, Thank you for explaining ABAQUS in a very simple way. Best video I found on TH-cam.. also, Can you please make a video on the Masonry wall (Brick etc) and explain about the Brick-Mortar joint and points related to masonry units? Really need it.. Thank you 🙂
Thank you, Dr Ahmed. But, do you mind sharing what apps you are using to open the CDP material data? Because I cannot open it by using spreadsheet/excel.
Thank you very much for your wonderful tutorials. My question is that if we have already all compression and tension-strain data what is the need for doing a compression test by ABAQUS? and the existing data for CDP ca be using for Masonry modeling?
Howdy Dr. Ahmed I would like to thank you pretty much… you helped me a lot to get started with the ABAQUS even though my work is concentrated on geotechnical... THANK YOU... I just need a help in getting started to input file and mesh generation if you have time to make like that explanation it would be very helpful for me and others. MANY THANKS
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 your previous 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
hello sir and thank you for the amazin tutorials.this excell that you use in this video is diffrent from the one that you placed it in the discribtion.is there any changes in the formulas from last year???
Thank you for always sharing helpful tutorials. I have a question concerning the type of analysis. You have mentioned in 13'55 that this analysis is a quasi-static one. I want to know why and based on what parameter you classified it so?
This means that the loading rate is very slow (10 sec), so eventho he is using the explicit solver (which is used for dynamic loadings mainly and mostly takes into consideration the inertia effects + Acc & Velocity), so this step is in name explicit but the load is slow enough to call it Quasi-Static. By definition, "Quasi-static load means the load is applied so slowly that the structure deforms also very slowly (very low strain rate) and therefore the inertia force is very small and can be ignored."
Thank you very much for the video! Very useful. I just don't understand why you used tie-rigid body constraints instead of pin-rigid body constraints you used in another video?
There will only be difference between tie and pin options, if the reference point rotates. In this example it does not, so the selected option does not matter. The documentation below provide clear description of the two options with illustrations: classes.engineering.wustl.edu/2009/spring/mase5513/abaqus/docs/v6.6/books/usb/default.htm?startat=pt01ch02s04aus20.html#usb-int-arigidoverview
Dear Dr.Ahmed Thank you for providing these tutorials. After I filled the properties for CDP, I am facing errors like, "Unknown keyword "concrete failure". The keyword may be misspelled, obsolete, or invalid. The material options *cap plasticity, *cast iron plasticity, *clay plasticity, *concrete, *concrete damaged plasticity, *drucker prager, *foam, *crushable foam, *mohr coulomb, *jointed material, *plastic and *soft rock plasticity are mutually exclusive Analysis Input File Processor exited with an error. Please let me know, if you have answers for this. Thanks!
Thank you Dr Ahmed for the great video. However, can we use Von Mises as a failure criterion in the concrete? as I know that the Von Mises criterion excludes the effect of the hydrostatic stress while the concrete is sensitive to that stress.
Not sure I fully understand your question. The CDP model plastic flow potential function is already dependandt on both the hydrostatic pressure stress and the Von Mises stress. When assessing failure/damage in post-processing, it is up to you to check any stress components or invarients of interest.
Hello Dr. Ahmed, Thank you for the informative video. I want to compare stress-strain curve from cylinder compression test with the material stress-strain graph......what will be the right procedure to pick the correct stress-strain data from the simulation result of the cylinder compression test... please guide me
Thanks for the video. Which material stress strain curve for tensile behavior? As I noticed that you didn't incorporate the effects of the element characteristic length. Also try to not fix the bottom and the upper end directly, it can give you a more 'realistic deformation'.
thank you for your great efforts and please we need more examples for stoky foundation such as pile caps if your time permit . and again thank you very much
@@AElkady im So Sorry, im continue the question. I've following your tutorial sir. Step by step (defining materials, modelling, BC, Job/Solving). but the results I get are much different from the modeling you did. To running in my PC its about 20minute. If you like, cab I send this file to your email sir? Please send to me the email adress 🙏
Hello Dr. Ahmed, the S Mises or Principal stress displayed in the output section (30.6 MPa) is more than the input stress values given originally in CDP test(29.1 MPa). Any idea why this kind of values are dispalyed and how to keep them below the input values?
Hi Dr Ahmed. I was wondering, can you do some tutorial of corrosion model for concrete on abaqus. I have difficulty in doing and i don't have references. Thank you and very appreciate it 😊
Dear Dr. Ahmed, Thank you for providing these tutorials. Regarding using the engineering values of stress-strain data, I wondered when to convert this eng stress-strain chart to true stress-strain?
Transformation of engineering stress-strain to the true one is mainly applicable to ductile materials that experience significant elongation and change in cross-section prior to failure. This does not need to be done for brittle material like concrete.
For this analysis, my job immediately aborts with the error "The independent variables must be arranged in ascending order. This error may have been caused by a possible empty line on the datacards in the property definition." but there is no empty line in my datacards
1) Discard all keyword edits to the model (if you did any) and re-write the keywords. 2) Make sure that your CDP data (such as damage parameter and strain data) are in ascending order and not repeatative).
I noticed that you have entered the density of the concrete as 2.4e-9 which is N per mm cubed. Thus this will translate into 2.4 N per meter cubed. But the actual density of concrete is 24 kN per meter cubed so the correct entry is 24e-6. Please correct me if I am wrong. Thank you and good work.
1) N or kN are force units not mass units. 2) In ABAQUS, if you are using SI (N and mm) units, then mass is defined in tons and density is defined in ton/mm3.
Thank you very much for the video. I was required to model element deletion in a concrete block when element temperature reaches specific value and specific failure strain in that temperature. How could I use these temperature dependent failure strains into my model?
When defining the material, you can choose to define "temprature-dependant" data. In that case, you will provide material properties definitions (including failure strain) as a function of temprature.
Thank you very much dear Prof, Can you tell me How do I make Abaqus stop the simulation once a critical value of Strain ot other has been reached? Please . And Thank You again.
In explicit analysis, you can use the *Extreme Element Valur keyword docs.software.vt.edu/abaqusv2022/English/SIMACAEKEYRefMap/simakey-r-extremeelementvalue.htm
Sir, i have Modelled Exactly like yours but the error occurs it says after the analysis that is the unknown keyword "concretefailure" How we can mitigate that Sir Kindly Guide me. Thanks
The only difference between static and dynamic loading is that in the latter you define a dynamic explicit step. In that step, time is relevant, therefore, you can then model how the applied load or displacement changes with time. Please see the tutorials on cyclic loads and explicit solver.
Sir will this helpful in shear failure of shaer critical beam,i am doing three point test of shaer critical beam and i am geting flexural failure,not shear failure please help me sir
dear Dr. Ahmed, Thank you for these useful videos, but when I do same steps I get an error "Unknown keyword "concretefailure;type=strain". The keyword may be misspelled, obsolete, or invalid" I use ABAQUs 2014
Hello sir I got the following error could you help me what does it mean IN THE PROPERTY DEFINITION. Job Job-cylinder-compression-sym: Analysis Input File Processor aborted due to errors. Error in job Job-cylinder-compression-sym: Analysis Input File Processor exited with an error. Job Job-cylinder-compression-sym aborted due to errors.
Hi Dr. Ahmed, thanks for the tutorials, there is just one problem I'm facing: when editing the keywords with the adding concrete failure, y Abaqus shows "Unknown keyword "concretefailure". The keyword may be misspelled, obsolete, or invalid." is it because of different versions? I'm using Abaqus 2017. Thanks!!!
I'm facing an error "step-1 and some elements have distorted excessively" in Dynamic-Explicit analysis. How to solve this error. please guide and if possible kindly make one video on most common errors and their solutions in Abaqus. Thank you.
A question please, I am doing a quasi static compression test on a polymeric structure and the compression rate is 0.1 mm/ sec applied for 6 mm, for a dynamic explicit time step shall I write 60 sec (1 min) or what?
That's correct although if you are not incorporating strain-rate effects, then your simulation step time does not need to be the same as that of the test. Iif you are simulating a quasi-static condition, you can use a much shorter step time as long as you don't induce dynamic forces in your model. Check the tutorial on explicit solver DOs and DONTs
I'm getting the error message that DAMAGESHR, PEEQVAVG, PEVAVG, SVAVG are not available for element type C3D8R. I imagine DAMAGESHR in particular is very important for this analysis, so how do I fix this issue? Are you supposed to use a different element type?
Field variables are available for specific element types and analysis procedurea, Please check this link for more details classes.engineering.wustl.edu/2009/spring/mase5513/abaqus/docs/v6.6/books/usb/default.htm?startat=pt02ch04s02abv01.html
Good afternoon sir, I want to know if the CDP model takes into account the strain rate and if yes would you mind mentioning the formulae? Thank you in advance
Most material models in ABAQUS "can" account for strain-rate effect IF specified by the user. For the CDP model, under the compression hardening and tension softening tabs, you can check the option to "use strain-rate dependant data" then you will need to provide the model parameters as a function of the different strain rates.
excuse sir but the problem I'm facing here is the lack of information ( inputs either in compression or tension ) about high-speed impact. For example, if I use the model depicted in Eurocode 2 for nonlinear analysis of reinforced concrete under compression. Do I have to check the strain rate option or that model would take into account the strain rate effect implicitly?
DURING THE CONVERSION FROM CRUSHING TO PLASTIC STRAIN Abaqus FOUND NEGATIVE AND/OR DECREASING VALUES OF PLASTIC STRAIN. VERIFY THAT THE DEGRADATION DATA UNDER *CONCRETE COMPRESSION DAMAGE IS CORRECT??????
Sir one question. In case of my problem, I am getting some lakhs of increment but in visualization module I can see only zero increment. But I can't see all the increment. Why is it like this?? Thanking you
@@AElkady Ahhh, I see. Noted on this. I am working right now on my Master Degree thesis, and I am using Abaqus Software. Actually, I did practiced your problem (4 point bending test) here in this video: th-cam.com/video/LBUhH-d3sxw/w-d-xo.html. I did all what is done in your video. To be honest, my thesis focus, too in 4-point bending test. But my problem is, the graph in the Force vs Displacement is not much of a non-linear graph, compare to the graph in your other videos like: th-cam.com/video/fYvUDo06e6c/w-d-xo.html. Do you think there's something that is wrong in my Input Data?
My probleme is that the fc28 that i have at the end of the analyse (33Mpa) is less than the value that i put at the parameter (43MPA) . Did you have any suggestion please ?
i follow the steps in the vidoe but the job aborted and this message appeared in errors (THE *CONCRETE FAILURE OPTION IS AVAILABLE FOR Abaqus/Explicit ONLY)
hi thanks for your unic tutorial. i do what you do step by step 3 turn but in eatch turn apear an error that sey: Error in job Concrete_Compression_Sym: THE INDEPENDENT VARIABLES MUST BE ARRANGED IN ASCENDING ORDER. THIS ERROR MAY HAVE BEEN CAUSED BY A POSSIBLE EMPTY LINE ON THE DATACARDS IN THE PROPERTY DEFINITION. can you help me?
may i ask about the time increment error and too many attempts error?? does these error associated with the material properties/meshes/step?? i dont really understand the concept of convergence yet im still blank on how to solve the problems.. and once i remove the CDP abaqus manage to read my model.. but when i apply CDP the errors keep on coming again..
I'm not sure I fully understand your question. There shouldn't be any errors related to "attempts" when using Abaqus explicit. Try to check the other tutorials on meshing and explicit solver Dos and DONTs.
Hello. Anyone got the CDP excel file to calculate parameters from Stress-strain either in compression or in tension? Basically the excel file shared in the video? I'd appreciate it. Thank you!
This is based on a typical cylinder compression test. No confinement. The litrature include simple modification to material strength and ductiltiy to account for confinment.
Thanks for you teaching. It helps a lot. When I edit keywords in the model the same way that you did, my job report an error: "Unknown keyword "concretefailure". The keyword may be misspelled, obsolete, or invalid." Do you know how can I solve it? Thank you again.
Dear @@AElkady thanks for the answer! When I compare the stress-strain curve obtained by the results of simulation with the original stress-strain curve (the input parameters), there are some considerable differences. These differences occurs mainly in the plastic part of the curve. Is that normal? There is some way to "calibrate" the results to obtain more accuracy in this stress-strain curve ?
@@windsonaguiar3690 that's expected particularly since I'm using a generic concrete material model parameters here that are not specifically obtained from a cylinder tests with these specific dimensions. Also, the plastic beahviour will rely on part on the stress distribution and failure mode being triggered in the model (both of which are dependadnt on the model imperfections as discussed in the video).
@@AElkady First of all thanks a lot for the videos🙏 I'm usin 2017 version and anyways I can't find the keyword "Concrete Failure" in the User's Manual. I'm having the same trouble as Windson.
This means there is a problem with your CDP data entry. As discussed in the tutorial, the strain/disp values need to be incrementatlly increasing (ascending order). Double check carefully the table values you entered for mistakes such as repeatative entries.
Unknown keyword error means that either: 1) keywork command is not written correctly or 2) your current ABAQUS version does not support this specific keyword
Didn't matter in this case since I only have one step, so Total time = Step time. Generally speaking, this depends on what you are trying to model (how would the amplitude vary during the entire analysis).
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 your previous 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 will be grateful if you have any other suggestion to deal with it. Thank you sir
What a brilliant series... The most complex things were dealt with an ease... Such a great learning experience...
Request you to have more lectures on storage bins with materials under seismic action or fluid with hydrodynamic actions...
Congratulations, the concept: Imperfection is very creative because the reality is always imperfection. Thank you so much
Dear A. Elkady
thank you for your clear explanation it is really useful
Hello Sir, Thank you for explaining ABAQUS in a very simple way. Best video I found on TH-cam.. also, Can you please make a video on the Masonry wall
(Brick etc) and explain about the Brick-Mortar joint and points related to masonry units? Really need it..
Thank you 🙂
The CDP material data used in this tutorial is available for download (see link in video description)
Thank you, Dr Ahmed. But, do you mind sharing what apps you are using to open the CDP material data? Because I cannot open it by using spreadsheet/excel.
Thank you very much for your wonderful tutorials. My question is that if we have already all compression and tension-strain data what is the need for doing a compression test by ABAQUS? and the existing data for CDP ca be using for Masonry modeling?
Howdy Dr. Ahmed I would like to thank you pretty much… you helped me a lot to get started with the ABAQUS even though my work is concentrated on geotechnical... THANK YOU... I just need a help in getting started to input file and mesh generation if you have time to make like that explanation it would be very helpful for me and others. MANY THANKS
Thank you so much for ur content Mr. Ahmad ❤.
Can u please do a video about the modelisation of the Nanoindentation technique
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 your previous 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
hello sir and thank you for the amazin tutorials.this excell that you use in this video is diffrent from the one that you placed it in the discribtion.is there any changes in the formulas from last year???
Thank you for always sharing helpful tutorials. I have a question concerning the type of analysis. You have mentioned in 13'55 that this analysis is a quasi-static one. I want to know why and based on what parameter you classified it so?
This means that the loading rate is very slow (10 sec), so eventho he is using the explicit solver (which is used for dynamic loadings mainly and mostly takes into consideration the inertia effects + Acc & Velocity), so this step is in name explicit but the load is slow enough to call it Quasi-Static.
By definition, "Quasi-static load means the load is applied so slowly that the structure deforms also very slowly (very low strain rate) and therefore the inertia force is very small and can be ignored."
Thank you very much for the video! Very useful. I just don't understand why you used tie-rigid body constraints instead of pin-rigid body constraints you used in another video?
There will only be difference between tie and pin options, if the reference point rotates. In this example it does not, so the selected option does not matter.
The documentation below provide clear description of the two options with illustrations:
classes.engineering.wustl.edu/2009/spring/mase5513/abaqus/docs/v6.6/books/usb/default.htm?startat=pt01ch02s04aus20.html#usb-int-arigidoverview
Dear Dr.Ahmed
Thank you for providing these tutorials.
After I filled the properties for CDP, I am facing errors like, "Unknown keyword "concrete failure". The keyword may be misspelled, obsolete, or invalid.
The material options *cap plasticity, *cast iron plasticity, *clay plasticity, *concrete, *concrete damaged plasticity, *drucker prager, *foam, *crushable foam, *mohr coulomb, *jointed material, *plastic and *soft rock plasticity are mutually exclusive
Analysis Input File Processor exited with an error.
Please let me know, if you have answers for this.
Thanks!
Same error occuring if you have mitigated this error kindly guide me also
Thanks a lot
Thank you Dr Ahmed for the great video. However, can we use Von Mises as a failure criterion in the concrete? as I know that the Von Mises criterion excludes the effect of the hydrostatic stress while the concrete is sensitive to that stress.
Not sure I fully understand your question. The CDP model plastic flow potential function is already dependandt on both the hydrostatic pressure stress and the Von Mises stress. When assessing failure/damage in post-processing, it is up to you to check any stress components or invarients of interest.
Hello Dr. Ahmed, Thank you for the informative video. I want to compare stress-strain curve from cylinder compression test with the material stress-strain graph......what will be the right procedure to pick the correct stress-strain data from the simulation result of the cylinder compression test... please guide me
Thanks for the video.
Which material stress strain curve for tensile behavior?
As I noticed that you didn't incorporate the effects of the element characteristic length.
Also try to not fix the bottom and the upper end directly, it can give you a more 'realistic deformation'.
thank you for your great efforts and please we need more examples for stoky foundation such as pile caps if your time permit . and again thank you very much
Thankyou Very Much For The Great Tutorial. Dr. Ahmed, How Much Time To Solving/Running This Model?
That depends on your pc specs. I believe this run took about 15min
@@AElkady im So Sorry, im continue the question. I've following your tutorial sir. Step by step (defining materials, modelling, BC, Job/Solving). but the results I get are much different from the modeling you did.
To running in my PC its about 20minute. If you like, cab I send this file to your email sir? Please send to me the email adress 🙏
Thanks Sir, This video is very interesting for numerical work.
Many thanks Mr Elkady
thank you for this video
can i ask you how much time did this model consume?
Tks for this video. the best i found.
Hello, how long did it took to run the analysis? Mine is processing for hours. Is it that i need a high spec computer?
Great video
Sir, Could you please make a video for applying temperature strain in ABAQUS. Thanks in advance
Hello Dr. Ahmed, the S Mises or Principal stress displayed in the output section (30.6 MPa) is more than the input stress values given originally in CDP test(29.1 MPa). Any idea why this kind of values are dispalyed and how to keep them below the input values?
Hello Dr. Ahmed Can you please tell me what is the best way to compare the stress-strain curve from this cylindrical data? with material behavior ?
Goood job on your course on Concrete damage plasticity, can u share ur data in the description, so we can use them too. Thanks a lot
The data used here are available for download (see link in video description)
Could you please upload full tutorial for modeling steel shear wall?
I only show video for comparing result with Experimental test.
Hi, thankyou for the video. I have a question, do we need to do our experiment proof first to get the values of strain and plot those in the abaqus?
The stress-strain data can be obtained from an actual cylinder test or it can be generated using empirical models that are available in litrature.
Hi Dr Ahmed. I was wondering, can you do some tutorial of corrosion model for concrete on abaqus. I have difficulty in doing and i don't have references. Thank you and very appreciate it 😊
Dear Dr. Ahmed,
Thank you for providing these tutorials.
Regarding using the engineering values of stress-strain data, I wondered when to convert this eng stress-strain chart to true stress-strain?
Transformation of engineering stress-strain to the true one is mainly applicable to ductile materials that experience significant elongation and change in cross-section prior to failure. This does not need to be done for brittle material like concrete.
For this analysis, my job immediately aborts with the error
"The independent variables must be arranged in ascending order. This error may have been caused by a possible empty line on the datacards in the property definition."
but there is no empty line in my datacards
1) Discard all keyword edits to the model (if you did any) and re-write the keywords. 2) Make sure that your CDP data (such as damage parameter and strain data) are in ascending order and not repeatative).
I noticed that you have entered the density of the concrete as 2.4e-9 which is N per mm cubed. Thus this will translate into 2.4 N per meter cubed. But the actual density of concrete is 24 kN per meter cubed so the correct entry is 24e-6. Please correct me if I am wrong. Thank you and good work.
1) N or kN are force units not mass units. 2) In ABAQUS, if you are using SI (N and mm) units, then mass is defined in tons and density is defined in ton/mm3.
@@AElkady Thanks I get it now
Thank you very much sir.
Which stress strain model are you using in your excel file?
Thank you very much for the video. I was required to model element deletion in a concrete block when element temperature reaches specific value and specific failure strain in that temperature. How could I use these temperature dependent failure strains into my model?
When defining the material, you can choose to define "temprature-dependant" data. In that case, you will provide material properties definitions (including failure strain) as a function of temprature.
Thank you very much dear Prof, Can you tell me How do I make Abaqus stop the simulation once a critical value of Strain ot other has been reached? Please . And Thank You again.
In explicit analysis, you can use the *Extreme Element Valur keyword
docs.software.vt.edu/abaqusv2022/English/SIMACAEKEYRefMap/simakey-r-extremeelementvalue.htm
@@AElkady Thank you very much Dear Prof. Warm Eid greetings to you and family .
@@AElkady Many thanks Deat Prof .
Thanks. Brilliant!
Sir, i have Modelled Exactly like yours but the error occurs it says after the analysis that is the unknown keyword "concretefailure" How we can mitigate that Sir Kindly Guide me. Thanks
Sir I am materials background. I want to adopt this for to a material or a composite. Can you suggest where I should do necessary changes?
Thank you so much for this video, sir ,when we develop pile driving model (concrete pile is used), how to apply the pile top load (Hammer impact)?
The only difference between static and dynamic loading is that in the latter you define a dynamic explicit step. In that step, time is relevant, therefore, you can then model how the applied load or displacement changes with time. Please see the tutorials on cyclic loads and explicit solver.
@@AElkady ok sir. Thank you very much.
Can you please suggest or make a videos on powder compaction simulation process?
جزاك الله خيرا
Sir will this helpful in shear failure of shaer critical beam,i am doing three point test of shaer critical beam and i am geting flexural failure,not shear failure please help me sir
Hello Dr.
I hope you are good.
My modal is getting aborted showing an error Unknown keyword "Concrete Failure"
What should i do please?
Regards
sir
can you make a tutorial about mesoscale model of concrete?
dear Dr. Ahmed,
Thank you for these useful videos, but when I do same steps I get an error "Unknown keyword "concretefailure;type=strain". The keyword may be misspelled, obsolete, or invalid"
I use ABAQUs 2014
i am getting same, did you get solution
@@ashok55ableyeah, you should use ver. 2019 or above.
Thanks :)
Hello sir, can you please tell which paoer you have used
Hello sir I got the following error could you help me what does it mean
IN THE PROPERTY DEFINITION.
Job Job-cylinder-compression-sym: Analysis Input File Processor aborted due to errors.
Error in job Job-cylinder-compression-sym: Analysis Input File Processor exited with an error.
Job Job-cylinder-compression-sym aborted due to errors.
Hi Dr Ahmed. May I know why "*Concrete Failure, TYPE=Strain" is an error for me after I submit the job..
What is the error?
@@AElkady Unknown Keyword. Is it because the keyword "*Concrete Failure, TYPE=Strain" only works for ABAQUS 2019+?
@@leechunyuan2638 Yes, this is a version issue
@@AElkady Alright. Thank you for the insightful video and the reply..
Dear sir, thank you for exising, add a patreon link so i can donate you for your good effort :)
Hi Dr. Ahmed, thanks for the tutorials, there is just one problem I'm facing: when editing the keywords with the adding concrete failure, y Abaqus shows "Unknown keyword "concretefailure". The keyword may be misspelled, obsolete, or invalid." is it because of different versions? I'm using Abaqus 2017. Thanks!!!
I think this works from the 2019 version and above
maybe because you miss the "*" before the concrete failure
I'm facing an error "step-1 and some elements have distorted excessively" in Dynamic-Explicit analysis. How to solve this error. please guide and if possible kindly make one video on most common errors and their solutions in Abaqus. Thank you.
A question please, I am doing a quasi static compression test on a polymeric structure and the compression rate is 0.1 mm/ sec applied for 6 mm, for a dynamic explicit time step shall I write 60 sec (1 min) or what?
That's correct although if you are not incorporating strain-rate effects, then your simulation step time does not need to be the same as that of the test. Iif you are simulating a quasi-static condition, you can use a much shorter step time as long as you don't induce dynamic forces in your model. Check the tutorial on explicit solver DOs and DONTs
Hi i have a question i put the concrete failure in the edit keywords but it shows error unknown keyword or invalid what should i do here plz help
I'm getting the error message that DAMAGESHR, PEEQVAVG, PEVAVG, SVAVG are not available for element type C3D8R.
I imagine DAMAGESHR in particular is very important for this analysis, so how do I fix this issue? Are you supposed to use a different element type?
Field variables are available for specific element types and analysis procedurea, Please check this link for more details classes.engineering.wustl.edu/2009/spring/mase5513/abaqus/docs/v6.6/books/usb/default.htm?startat=pt02ch04s02abv01.html
Good afternoon sir, I want to know if the CDP model takes into account the strain rate and if yes would you mind mentioning the formulae? Thank you in advance
Most material models in ABAQUS "can" account for strain-rate effect IF specified by the user. For the CDP model, under the compression hardening and tension softening tabs, you can check the option to "use strain-rate dependant data" then you will need to provide the model parameters as a function of the different strain rates.
excuse sir but the problem I'm facing here is the lack of information ( inputs either in compression or tension ) about high-speed impact. For example, if I use the model depicted in Eurocode 2 for nonlinear analysis of reinforced concrete under compression. Do I have to check the strain rate option or that model would take into account the strain rate effect implicitly?
DURING THE CONVERSION FROM CRUSHING TO PLASTIC STRAIN Abaqus FOUND NEGATIVE AND/OR DECREASING VALUES OF PLASTIC STRAIN. VERIFY THAT THE DEGRADATION DATA UNDER *CONCRETE COMPRESSION DAMAGE IS CORRECT??????
its my bad 0.0006 I miss on 0.00
Sir one question. In case of my problem, I am getting some lakhs of increment but in visualization module I can see only zero increment. But I can't see all the increment. Why is it like this??
Thanking you
make sure that the saving increment within the field/history output request is set properly.
It’s working now sir. Thank you sir
I also have question here, in the Reference Point in assigning Constraint, why is it that you use Tie instead Rigid Body?
both would work in that example.
@@AElkady Ahhh, I see. Noted on this.
I am working right now on my Master Degree thesis, and I am using Abaqus Software. Actually, I did practiced your problem (4 point bending test) here in this video: th-cam.com/video/LBUhH-d3sxw/w-d-xo.html. I did all what is done in your video. To be honest, my thesis focus, too in 4-point bending test. But my problem is, the graph in the Force vs Displacement is not much of a non-linear graph, compare to the graph in your other videos like: th-cam.com/video/fYvUDo06e6c/w-d-xo.html. Do you think there's something that is wrong in my Input Data?
By the way, my time = 1.0, and my increment is 0.05... is the time and increment has something to do with the graph?
What if I apply a small horizontal load to trigger imperfection instead of modifying the model? Does it make difference?
May be...You'll have to try and see.
My probleme is that the fc28 that i have at the end of the analyse (33Mpa) is less than the value that i put at the parameter (43MPA) . Did you have any suggestion please ?
sorry, I don't thick I understand your question.
i follow the steps in the vidoe but the job aborted
and this message appeared in errors (THE *CONCRETE FAILURE OPTION IS AVAILABLE FOR Abaqus/Explicit ONLY)
hi thanks for your unic tutorial.
i do what you do step by step 3 turn but in eatch turn apear an error that sey:
Error in job Concrete_Compression_Sym: THE INDEPENDENT VARIABLES MUST BE ARRANGED IN ASCENDING ORDER. THIS ERROR MAY HAVE BEEN CAUSED BY A POSSIBLE EMPTY LINE ON THE DATACARDS IN THE PROPERTY DEFINITION.
can you help me?
This means you probably made a typo when you edited the keywords to add concrete failure. Re-check the keywords.
may i ask about the time increment error and too many attempts error?? does these error associated with the material properties/meshes/step?? i dont really understand the concept of convergence yet im still blank on how to solve the problems.. and once i remove the CDP abaqus manage to read my model.. but when i apply CDP the errors keep on coming again..
I'm not sure I fully understand your question. There shouldn't be any errors related to "attempts" when using Abaqus explicit. Try to check the other tutorials on meshing and explicit solver Dos and DONTs.
Why can’t I get the 45-angle deformation after setting the defect in the same way as the video? Is the same as no defect
Could be that the mesh was generated in a different matter. try increasing the imperfection.
Hello.
I have some questions about modeling on the program, can you help me?
Please post your questions here and I will try to help
Hello. Anyone got the CDP excel file to calculate parameters from Stress-strain either in compression or in tension? Basically the excel file shared in the video? I'd appreciate it. Thank you!
can we add randomly distributed aggregate into this cocnrete cylinder?
I believe your question refers to discrete element method which is a different approach to what is described in this tutorial.
Hi dear Dr this cdp file used for confined concrete or not?
This is based on a typical cylinder compression test. No confinement. The litrature include simple modification to material strength and ductiltiy to account for confinment.
Thanks for you teaching. It helps a lot.
When I edit keywords in the model the same way that you did, my job report an error: "Unknown keyword "concretefailure". The keyword may be misspelled, obsolete, or invalid." Do you know how can I solve it?
Thank you again.
You need to make sure you follow the syntax exactly. It is case sensitive. Also, this keywork is available in ABAQUS 2019 and later versions.
Dear @@AElkady thanks for the answer!
When I compare the stress-strain curve obtained by the results of simulation with the original stress-strain curve (the input parameters), there are some considerable differences. These differences occurs mainly in the plastic part of the curve. Is that normal?
There is some way to "calibrate" the results to obtain more accuracy in this stress-strain curve ?
@@windsonaguiar3690 that's expected particularly since I'm using a generic concrete material model parameters here that are not specifically obtained from a cylinder tests with these specific dimensions. Also, the plastic beahviour will rely on part on the stress distribution and failure mode being triggered in the model (both of which are dependadnt on the model imperfections as discussed in the video).
@@AElkady
First of all thanks a lot for the videos🙏
I'm usin 2017 version and anyways I can't find the keyword "Concrete Failure" in the User's Manual. I'm having the same trouble as Windson.
@@naniruja3407 Including the Concrete Failure option is not a critical material property and mostly cosmetic.
Hello sir, it's nice video but I have a doubt.
I get error like this " independent variables must be arranged in assending order" what can I do sir.
This means there is a problem with your CDP data entry. As discussed in the tutorial, the strain/disp values need to be incrementatlly increasing (ascending order). Double check carefully the table values you entered for mistakes such as repeatative entries.
Sir, can you explain it in separate video
@Ahmed Elkady Could you please publish the excel sheet?
It's on GitHub now.
Aoa how can I resolve this issue of unknown keyword.. iv followed all steps
Unknown keyword error means that either: 1) keywork command is not written correctly or 2) your current ABAQUS version does not support this specific keyword
Sir could you please share excel sheet it will better to understand cdp Thankyou sir
please can you attach excel file that calculate inelastic strain
💚💚💚💚
18:08 Time span: Step time or Total Time???
Didn't matter in this case since I only have one step, so Total time = Step time. Generally speaking, this depends on what you are trying to model (how would the amplitude vary during the entire analysis).
@@AElkady Got it. Thank you so much. You have been very helpful 🙏🏻
is it possible to have the source for the excel file?
:D
Will publish it soon.
Like
Respected Dr Ahmed. Thank You so much for explaining so well. Can I get your LinkedIn or Facebook Id please?
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 your previous 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 will be grateful if you have any other suggestion to deal with it. Thank you sir