After countless hours of research and trial & error I have now finanlly created and validated a working ABAQUS model for a tensile test of a steel specimen with damage evolution. The official ABAQUS documentation is unfortunatly so bad... Is that by design so that I buy the official abaqus course ? There are countless threads on the internet on how to determine the basic input properties for the damage for ductile metals material model - ductile damage. To the best of my knowledge all of them are either wrong, partially wrong or incomplete. Nobody seems to know all the correct details... UNTIL NOW ! One of the main points everyone gets wrong is the Parameter L which is according to the abaqus manual, the characteristic element length. However, I have read the official ABAQUS Course: Modeling Fracture and Failure with Abaqus and here L is the gauge length of the tensile test specimen which belongs to the stress-strain input data ! Also I was not sure about the definition of the fracture strain, because there are many confusing threads on the internet and nobody seems to know "how ABAQUS defines the fracture strain". The fracture strain is the corresponding strain at damage initiation and not the rapture strain of failure strain of the test. I will upload a longer version of this video in the coming days which shows every step in an excel sheet.
@hellosushant94712 жыл бұрын
waiting
@hnrwagner2 жыл бұрын
@@hellosushant9471 at least one :)
@Jade-jv6eq2 жыл бұрын
hi Dr. Ing. Ronald Wgner, thank you for sharing which deepen my knowledge. Would you mind sharing 《Modeling Fracture and Failure with Abaqus》, You demonstrate 3 methods to calculate characteristic element length in your video, one is element length, one is IVOL^(1/3), another one is the gauge length of the tensile test specimen. they are quite different and confusing, which one is correct?
@user-nh9fb8wb4s Жыл бұрын
@@hnrwagner i have same question with Jade (above comment)
@nabilishes Жыл бұрын
Do you have any link to the ABAQUS Course: Modeling Fracture and Failure with Abaqus powerpoints/handouts?
@hnrwagner2 жыл бұрын
#abaqus #metal #hnrwagner #ductiledamage Reference for Thumbnail Figures: www.researchgate.net/publication/304186947_Effects_of_Workshop_Fabrication_Processes_on_the_Deformation_Capacity_of_S960_Ultra-high_Strength_Steel Slides of the presentation: www.researchgate.net/publication/360927265_The_ultimate_quick_guide_to_damage_for_ductile_metals_-_ductile_damage_for_ABAQUS_CAE Github Link: github.com/hnrwagner/UMAT_Lecture_1 Google Scholar: scholar.google.de/citations?user=a4sKEKsAAAAJ&hl=en Researchgate: www.researchgate.net/profile/Ronald-Wagner Timecodes: 0:00 - Intro 0:14 - Engineering Stress-Strain Curve 0:23 - True Stress-True Strain Curve 0:29 - E-Modulus, Yield and Ultimate Stress 0:38 - True Stress-Plastic Strain Curve 0:48 - Fracture Strain 1:05 - True Stress-Displacement Curve 1:56 - Determine Damage Variable and Plastic Displacement 2:21 - Damage Evolution - Tabular Plastic Displacement 2:24 - Damage Evolution - Linear Plastic Displacement 2:29 - NO Damage Evolution - Plastic Displacement = 0 2:34 - Fracture Energy 2:44 - ABAQUS model geometry 2:48 - Material data input for ABAQUS 3:26 - Reference Point - Rigid Body Constraint 3:36 - Boundary Conditions 3:48 - Field Output, STATUS Variable 3:56 - Element Deletion Settings 4:06 - How to plot stress-strain curve ? 4:31 - True Stress-True Strain - no damage evolution -Test/ABAQUS 4:51 - ABAQUS - Tensile test - no damage evolution 5:11 - True Stress-True Strain - linear damage evolution -Test/ABAQUS 5:18 - ABAQUS - Tensile test - linear damage evolution 5:45 - True Stress-True Strain - tabular damage evolution -Test/ABAQUS 5:52 - ABAQUS - Tensile test - tabular damage evolution 6:06 - Comparison of all models with test data 6:30 - How to improve the damage evolution ? 7:36 - Final results 7:51 - References and Ending
@GauravMishra-hf1pg7 ай бұрын
Great explanation with example. Thanks Dr. Wagner
@mangeshpatil6382 Жыл бұрын
Thank you very much Dr Wagner for your time. You have explained damage in details with different test cases. Would like to see some video on Fesafe .
@hnrwagner Жыл бұрын
Never used fesafe unfortunately
@joaovictorsantos56603 ай бұрын
Great explanation Dr. Wagner. Could you show your "steps" configurations? Did you set Non-lineartity on?
@leicai-eg1nt Жыл бұрын
really awesome, I am shocked by so many useful videos
@hnrwagner Жыл бұрын
thanks
@vitorgomes6712 жыл бұрын
Awesome content. Thanks for sharing your knowledge. Your videos help me a lot.
@hnrwagner2 жыл бұрын
Good to hear, thanks
@peggyk31042 жыл бұрын
Thank you very much for this enlightening video. Great work! Regarding the parameter L, the ABAQUS course refers again that "The characteristic length L is computed automatically by Abaqus based on element geometry." and "The damage evolution law can be specified either in terms of fracture energy (per unit area) or in terms of the equivalent plastic displacement and that Both approaches take into account the characteristic length of the element." While somewhere in the beginning the characteristic length is correlated to the ASTM standards provided lengths. That still causes some confusion. It would be very helpful if you could include some additional information regarding the Characteristic length definition as the gauge length of a tensile specimen
@hnrwagner2 жыл бұрын
I will add a video with more information regarding the Characteristic length definition as the gauge length of a tensile specimen in the future
@kayagunduz7490 Жыл бұрын
Thanks you for the knowledge
@nikitarozin Жыл бұрын
Great work! Thank you a lot for sharing your knowledge.
@bencherifmokhtar14292 жыл бұрын
thnak you Dr. Wagner, you're a good help to us
@hnrwagner2 жыл бұрын
thanks
@KirillKlyshnikov2 жыл бұрын
Thank you very much!
@hnrwagner2 жыл бұрын
a pleasure for me :)
@SovannDimanche Жыл бұрын
Thank you very much for this helpful video. I hope you can make tutorial about adhesive element .
@user-vl5hi2bs7v Жыл бұрын
Thank you for the information Dr Wagner, it really helps doing my experiments. I have one question. Is stress-strain curve you used in the video obtained from quasi-static condition? Thanks a lot Dr.
@hnrwagner Жыл бұрын
Yes it's from quasi static test
@user-vl5hi2bs7v Жыл бұрын
@@hnrwagner Thank you sir! Always thanks for your videos!
@user-vl5hi2bs7v Жыл бұрын
@@hnrwagnerDoctor, I apologize for the late question, but I have one more question. Is it necessary to use a round specimen for the ductile damage experiment? I am curious whether it is affected by rolling direction when using a flat specimen. Thank you always for your kind answers.
@hnrwagner Жыл бұрын
@@user-vl5hi2bs7v the shape of the stress Strain curve is slightly different for a round specimen compared to a flat specimen
@user-vl5hi2bs7v Жыл бұрын
@@hnrwagner Thanks for your response sir! It really helps!
@rabindrasubedi41502 жыл бұрын
Nice presentation, have you done any high cycle fatigue analysis in ABAQUS. Thank you in advance
@hnrwagner2 жыл бұрын
No haven't done it yet, do you have a reference, than i may take a look at it
@umitjhukov66622 жыл бұрын
Thank you very much for this amazing video, I could really use some help in determination of Damage variable and plastic displacement, In the sake of finding the damage variable do you use the stress values that co-respond to the same plastic displacement value? how do you determine the offset value for the elastic functions(slope*strain+offset=stress)? Thank you for your help Have a nice day
@hnrwagner2 жыл бұрын
I will upload a long video on this topic, this will clarify everything
@umitjhukov66622 жыл бұрын
@@hnrwagner hello again sir thank you for your response, Even tho I was able to solve my issues myself the abaqus is giving errors and acting in a relatively weird way. I assign a max degradation of 0.95 just like you but abaqus does not delete the mesh at 0.95 criteria instead criteria goes up to thousands and analysis gets aborted due to extensive disorientation How could I resolve this issue Best regards Good day
@dzej11311 ай бұрын
@@umitjhukov6662 have you enabled the "STATUS" variable in the field output request? Abaqus won't delete elements if the STATUS variable is inactive.
@yamanarslanca43372 жыл бұрын
Thanks for the video Dr. Wagner. I want to ask a question, why did not you leave the Max Degradation value at default (which is 1) and changed it to 0.95 instead ?
@hnrwagner2 жыл бұрын
This was a recommendation from an abaqus expert, the last 5% may lead to unnecessary long computation time without extra benefit in accuracy, in my example it makes actually barely a difference. I just want to share some tips and tricks from other professionals :)
@steveokocha9860 Жыл бұрын
Can the same fracture energy be used for smooth tensile specimen and other different notch round bar (NBR) specimen of the same material???
@hnrwagner Жыл бұрын
No the energy has to be calculated for each specimen geometry
@steveokocha9860 Жыл бұрын
@@hnrwagner thanks very much Dr. Last question: if that's the case. Is the fracture strain (strain at ultimate stress) attained from smooth tensile test also used for NRB specimens. ? Or would it be different ?
@vincaldhool94533 ай бұрын
slide @ time 2.11 shows stress = 273MPa on graph but in damage computation you use stress = 237MPa ? Is it a typing mistake or is there another reason
@hnrwagner3 ай бұрын
its a typo,thanks
@sejong4672 Жыл бұрын
Thank you so much 😊 Could you explain how the model recognizes the fracture should occur along the maximum shear stress direction (45 Deg)?
@user-yh8xw6ub7n Жыл бұрын
Thank you for your garatful help to understand Abaqus analysis. I would like to have a question. Is the fracture engergy in this video equivalent with the energy release ratio which can be define from fracture toughness based on material property ?
@RivuRana-sb8eo Жыл бұрын
Sir thank you for this informative video about ductile material. It's very helpful for me as I am working on ductile zones . I have a question sir if I will use a rectangular bar (maybe 100*20 scale) then what is the gauge length for my modelling? Could you please explain how to get plastic displacement?
@yifanzhi2648 Жыл бұрын
Hi,could I ask some questions?I remember you has a video calculating fracture energy by characteristic length.Could I know how could decide to use the specific way to calculate JC damage evolution fracture energy? And actually for my personal project, the UTS is 128MPa and fracture point is about 126 MPa (strain difference is 0.005).The calculated value seems only 8% of the energy value which I type in Abaqus and think the simulation result graph is close to experimental true stress strain graph.I am very confused about calculating the fracture energy so is it possible to get more suggestions?Here thank you very much for you videos.It makes me understanding corressponding Abaqus manual meaning.Thank you very much!
@user-nh9fb8wb4s2 жыл бұрын
thank you for this great video. i have question why did you calculate u_f at damage variable not d=1 but d=0.99 ?
@hnrwagner2 жыл бұрын
that a recommendation from the abaqus course, because the slope of the function you need to determine the plastic displacement is zero, it may cause problems in the analysis (very long computation time)
@user-nh9fb8wb4s2 жыл бұрын
@@hnrwagner thanks
@user-nh9fb8wb4s2 жыл бұрын
@@hnrwagner Dr. Wagner, May I ask one more question? can i apply your method to define fracture energy / displacement at failure values in traction separation laws - maxps - damage evolution ? is it just for ductile damage?
@hnrwagner2 жыл бұрын
@@user-nh9fb8wb4s i do not know, i will check
@azz650 Жыл бұрын
Amazing tutorial, I have a question on why in the fracture energy equation we have a 2 factor ?
@hnrwagner Жыл бұрын
Its the area of a triangle and you calculate this using length times witdh divided by 2
@arumys9303 Жыл бұрын
Thank you for the useful video. I was wondering how to calculate the displacement at failure, do you have a tutorial about it?
@hnrwagner Жыл бұрын
at 2:20 it is shown in the video...
@arumys9303 Жыл бұрын
@@hnrwagner Yes, I mean an excel tutorial to calculate the displacement at failure🙏
@atakhabaz3607 Жыл бұрын
Thank you for your time and effort. However, it made a big question to me. In some other FE simulations, such as CZM, damage parameters are introduced to be depend to the mesh length. It means that whenever you refine the mesh size your damage evolution parameters should change. Have you ever seen them? or what do you think?
@hnrwagner Жыл бұрын
They depend on the mesh BUT internally, so abaqus calculates the values itself, in this model you do not need to adjust the input parameters to the mesh
@user-nr1qm8ie3h Жыл бұрын
In the damage parameters, the failure strain should be the effective plastic strain. I think you input 0.073 incorrectly!
@hnrwagner Жыл бұрын
I learned it that way in the official abacus course, it should be correct. Results also match well with the test. What should the value be in your opinion
@user-nr1qm8ie3h Жыл бұрын
I think we should subtract the elastic strain, don't you think? After all, there is no damage or plastic strain during the elastic stage@@hnrwagner
@nimash40982 жыл бұрын
Thank you so much for the great tutorial videos. Just a question. Why do you put 0 for stress triaxility? Your model is uniaxial tension loading. I think stress triaxiality should be 0.33 for this case.
@hnrwagner2 жыл бұрын
this value is only needed if you have more than 1 fracture strain, alone it has no value
@nimash40982 жыл бұрын
@@hnrwagner Thank you so much
@TheSh258911 ай бұрын
Thank you for your great lecture, But I have one question, when you get stress-displacement curve. why do you use true strain rather than engineering strain? because I think that using engineering strain is actual displacement by multiplying gauge length.
@TheSh258911 ай бұрын
Also I confused that as I know, length L to get damage variables, L is characteristic length of the element.
@hnrwagner11 ай бұрын
the video was done all according to official ABAQUS lecture, there true strain was used and so on@@TheSh2589
@TheSh258911 ай бұрын
I understand but I found the related contents in Abaqus documentation, Abaqus analysis user's guide 24.1.1, 24.2.1 and 24.2.3 , they define L as element characteristic length
@UBW77882 жыл бұрын
I'm wondering if it's still valid to compute true stress/true strain like you shown in Slide 4 in the necking section of the stress-strain curve. Usually, people estimate the true stress-strain behavior in necking region as an extended line to the true rupture strain. It's kind of important as it's related to your plastic displacement calculation later on. thank you.
@hnrwagner2 жыл бұрын
cant say for sure, the ABAQUS user manual gives no information regarding area after necking. However, as the simulation results is quite close to the test, this approach seems to be accurate enough
@jarmohavula65879 ай бұрын
It seems that the function used to calculate the true stress does not apply after necking starts (volume is not constant after that, etc.). So. I agree that the true stress-strain curve should continue as a straight line. Actually, after necking starts, the cross section change should be measured/ evaluated with a proper method, like DIC, and then the true stress should be calculated using the measured cross section area.
@suryanto51252 жыл бұрын
Thanks for the explanation Sir. I have any question, a. In the simulation you use load control/displacement control/velocity control? And what value did you enter Sir? b. Also do you use mass scaling Sir?
@hnrwagner2 жыл бұрын
Displacement control of 10 mm and no mass scaling
@suryanto51252 жыл бұрын
@@hnrwagner Okay Sir. I used a step time of up to 2400 in my project with a displacement control of 10. However, my specimen has not broken Sir. Do you know how to determine the correct step time and displacement control values Sir?
@akshaydengwani39162 жыл бұрын
@@hnrwagner Even my model is not failing I used displacement control of 10mm using amplitude (0,0) and (1,1)
@hnrwagner2 жыл бұрын
@@akshaydengwani3916 have you the same model as in the video or a different? (material, geometry) when in doubt use 100 mm
@akshaydengwani39162 жыл бұрын
@@hnrwagner Yes Sir I have replicated everything same. I will try with higher value once.
@gabrielaguirre64476 ай бұрын
Do you have a book where I can find this theory?
@hnrwagner6 ай бұрын
no, its based on an official abaqus course
@mariogalindoq5 ай бұрын
From 1:08 to 2:30 you are drawing Displacement vs Stress but you are labeling the Displacement as Plastic Displacement. Why?
@hnrwagner5 ай бұрын
its defined like this in the official abaqus regarding damage models when i am not mistaken
@mariogalindoq5 ай бұрын
@@hnrwagner sorry but something is wrong. During the linear elastic part of the deformation you don't have Plastic Displacement. Your graphic is saying the opposit.
@hnrwagner5 ай бұрын
@@mariogalindoq you are right, I just checked the documents again, it should be "total displacement u" only the last part after damage initiation is defined as plastic displacement
@mariogalindoq5 ай бұрын
@@hnrwagner I understand that the Plastic Displacement starts just after the yield point at the end of the linear elastic deformation. However, for the damage evolution it is necessary to subtract the Plastic Displacement defined at the damage initiation point. Therefore, for the Damage computation, you should use Up-Up0 being Up the current Plastic Displacement and Up0 the Plastic Displacement at the damage initiation point (normally the Plastic Displacement corresponding to the maximum stress) only when Up>Up0. Do you agree? Thank you for your answer. I found good videos in your channel.
@akshaydengwani39162 жыл бұрын
What is the Load Value used in ABAQUS CAE is it Force or Displacement ?
@hnrwagner2 жыл бұрын
Displacement = 10 mm
@akshaydengwani39162 жыл бұрын
@@hnrwagner Danke Professor
@user-fi2gh3kn7m Жыл бұрын
Hi. i want to know can use this method for all of Ductile material or there is exception ?
@hnrwagner Жыл бұрын
Cant say,you should Read the abaqus manual, it works for metals okish,dont know What you want to model
@mariogalindoq5 ай бұрын
Rapture or Rupture?
@hnrwagner5 ай бұрын
Rupture :P
@duonghoang6855 Жыл бұрын
How can I get the number 14621, sir?
@hnrwagner Жыл бұрын
You get it from curve fitting with excel
@jasonf8080 Жыл бұрын
Thank you very much. I would like to ask, is there a formula for rough estimation of fracture energy, in case where the stress-strain curve is not available and only yield stress and ultimate stress data is available?
@hnrwagner Жыл бұрын
In this case i would assume fracture energy = 0
@jasonf8080 Жыл бұрын
@@hnrwagner If so, where do we input the fracture toughness (KIC) data of the material being used?
@hnrwagner Жыл бұрын
@@jasonf8080 there is no fracture toughness in ABAQUS for damage for ductile metals only fracture energy, see at 3:19
@jasonf8080 Жыл бұрын
@@hnrwagner Alright, thank you very much
@kikinano58302 жыл бұрын
I need to know the properties of aluminum 2024
@hnrwagner2 жыл бұрын
which properties exactly?
@kikinano58302 жыл бұрын
@@hnrwagner strain rate triaxiality stress and displacement
@hnrwagner2 жыл бұрын
@@kikinano5830 ok and have you already checked Google scholar or only Google? That what i would do