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.

#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

Great explanation with example. Thanks Dr. Wagner

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 .

Great explanation Dr. Wagner. Could you show your "steps" configurations? Did you set Non-lineartity on?

really awesome, I am shocked by so many useful videos

Awesome content. Thanks for sharing your knowledge. Your videos help me a lot.

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

Thanks you for the knowledge

Great work! Thank you a lot for sharing your knowledge.

thnak you Dr. Wagner, you're a good help to us

Thank you very much!

Thank you very much for this helpful video. I hope you can make tutorial about adhesive element .

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.

Nice presentation, have you done any high cycle fatigue analysis in ABAQUS. Thank you in advance

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

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 ?

Can the same fracture energy be used for smooth tensile specimen and other different notch round bar (NBR) specimen of the same material???

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

Thank you so much 😊 Could you explain how the model recognizes the fracture should occur along the maximum shear stress direction (45 Deg)?

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 ?

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?

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!

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 ?

Amazing tutorial, I have a question on why in the fracture energy equation we have a 2 factor ?

Thank you for the useful video. I was wondering how to calculate the displacement at failure, do you have a tutorial about it?

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?

In the damage parameters, the failure strain should be the effective plastic strain. I think you input 0.073 incorrectly!

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.

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.

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.

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?

Do you have a book where I can find this theory?

From 1:08 to 2:30 you are drawing Displacement vs Stress but you are labeling the Displacement as Plastic Displacement. Why?

What is the Load Value used in ABAQUS CAE is it Force or Displacement ?

Hi. i want to know can use this method for all of Ductile material or there is exception ?

Rapture or Rupture?

How can I get the number 14621, sir?

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?

I need to know the properties of aluminum 2024