I had been reading through a paper on determination of JC parameters and your 6 minute video made clear as day! Thanks, PhD Student at University of Bristol.
Currently we have the following damage models explained on this channel: Ductile Hashin Johnson-Cook Concrete Damage Plasticity Which one of the following should I cover next ? abaqus-docs.mit.edu/2017/English/SIMACAECAERefMap/simacae-m-PrpMechanicalDamage-sb.htm Maxe or Quade Maxs or Quads Maxps or Maxpe M-K MSFLD Shear Mullins Effect FLD FLSD
Hello sir, I really like your videos and learn a lot from them even thou I prefer using Ls-Dyna instead of using abaqus while using Johnson Cook Material card I also have to define EOS(Equation of State) so maybe you could explain us what are EOS and how to define them in these simulation aplications.
Here you use the strain value 0.2% times the ultimate strain, then conclude the stress as the yield stress. But, why you don't use the stress corresponding to strain 0.002 as a yield stress directly? This method is used in Material mechanics text book.
Dear Dr.-Ing. Ronald Wagner, great video but I have one question, Why not add 0.002 directly, but add 0.0005 ( 0.2 * 0.25 * 0.01 ), yield stress is not 0.2 % strain when the stress ?
Dear Dr.-Ing. Ronald Wagner, thank you for the video. I have a question for you. During the determination of B and n constants, you used the graph of ln (true stress-yield stress) - ln (true strain). Don't you think it is more appropriate to use true plastic strain instead of true strain? Can you explain? Thanks.
Dear Dr-Ing. Wagner. I am having trouble with the nomeclature. Wouldn´t in this case be the engineering stress and the engineering strain? From what I understand, true stress and strain are found in a flow curve, not in a stress-strain diagram. I have to find the parameters regarding some experiments, however I have the flow curves and not the engineering stress-strai diagram, therefore I would like to solve this small doubt. Thank you for the video
Hi, I have been searching around and I have not come across any videos for determination of Johnson Holmquist Ceramic parameters, do you have any recommendation or could you do a video on this? It would be greatly appreciated.
@@hnrwagner Thank you for your quick reply. Suppose experimental temp range are 250, 300, 350, 400, 450, 500 degree C, and strain rate are 10^-3, 10^-2, 10^-1, 1, 10 /sec. Then what should be the ref temp and ref strain rate?
Hi, great video but I have one question, did your stress strain curves are converted into curves without elastic region? Because in my case the beggining of the curve looks more like half of the parabola and I am little confused cause of it because I can't even use offset method properly. Would be greatfull for your answer. Thanks.
@@hnrwagner The test was done by Dr. from my university so I thought it should be done properly but now I think it looks like slight loosening of the sample at the beginning. After strain reach 2% everythink looks fine.
I had been reading through a paper on determination of JC parameters and your 6 minute video made clear as day! Thanks, PhD Student at University of Bristol.
Currently we have the following damage models explained on this channel:
Ductile
Hashin
Johnson-Cook
Concrete Damage Plasticity
Which one of the following should I cover next ?
abaqus-docs.mit.edu/2017/English/SIMACAECAERefMap/simacae-m-PrpMechanicalDamage-sb.htm
Maxe or Quade
Maxs or Quads
Maxps or Maxpe
M-K
MSFLD
Shear
Mullins Effect
FLD
FLSD
Hello sir, I really like your videos and learn a lot from them even thou I prefer using Ls-Dyna instead of using abaqus while using Johnson Cook Material card I also have to define EOS(Equation of State) so maybe you could explain us what are EOS and how to define them in these simulation aplications.
Thank you for this very informative video, makes it so much easier to understand!
appreciate your comment
Excellent
Good job Dr Ronald.
Thank you. Its very helpful
Here you use the strain value 0.2% times the ultimate strain, then conclude the stress as the yield stress. But, why you don't use the stress corresponding to strain 0.002 as a yield stress directly? This method is used in Material mechanics text book.
Dear Dr.-Ing. Ronald Wagner, great video but I have one question, Why not add 0.002 directly, but add 0.0005 ( 0.2 * 0.25 * 0.01 ), yield stress is not 0.2 % strain when the stress ?
I'am sorry. I am wrong.
我也感觉他写错了 直接加0.2%就可以
Thanx for the video, can you please upload the determination of C and temperature Coefficient (m) calculation
Only for patreons of this channel
thanks
Dear Dr.-Ing. Ronald Wagner, thank you for the video. I have a question for you. During the determination of B and n constants, you used the graph of ln (true stress-yield stress) - ln (true strain). Don't you think it is more appropriate to use true plastic strain instead of true strain? Can you explain? Thanks.
have not tried it, the references i read used the true strain. I guess it has not a big influence, but i am not sure.
Dear Dr-Ing. Wagner. I am having trouble with the nomeclature. Wouldn´t in this case be the engineering stress and the engineering strain? From what I understand, true stress and strain are found in a flow curve, not in a stress-strain diagram. I have to find the parameters regarding some experiments, however I have the flow curves and not the engineering stress-strai diagram, therefore I would like to solve this small doubt. Thank you for the video
Hi, I have been searching around and I have not come across any videos for determination of Johnson Holmquist Ceramic parameters, do you have any recommendation or could you do a video on this? It would be greatly appreciated.
Nice video!! I hava one question. Why do you calculate the previous parameters (A B n) first, aren‘t they in a formula?
I do not understand your question, could u be a more specific?
Parameter A is the yield strength at room temperature and a strain rate of 1/s. ???
no in this example, A is the yield stress (0.02 % approximation) for a strain rate of 0.05 1/s at room temperatur
@@hnrwagner if so then in the video "how to obtain the johnson cook parameter C..." Value Ln(strain rate) = Ln(strain rate/0,05) ?
How the reference temp and reference strain are selected?
Room temperature and strain rate for quasi static behavior
@@hnrwagner Thank you for your quick reply.
Suppose experimental temp range are 250, 300, 350, 400, 450, 500 degree C, and strain rate are 10^-3, 10^-2, 10^-1, 1, 10 /sec. Then what should be the ref temp and ref strain rate?
@@barman5186 room temperature is 20 °C as strain rate i would set the lowest value (10^-3)
Hi, great video but I have one question, did your stress strain curves are converted into curves without elastic region? Because in my case the beggining of the curve looks more like half of the parabola and I am little confused cause of it because I can't even use offset method properly. Would be greatfull for your answer. Thanks.
you mean you cant determine the yield stress with the offset method because of your curve? was the material test done properly?
@@hnrwagner The test was done by Dr. from my university so I thought it should be done properly but now I think it looks like slight loosening of the sample at the beginning. After strain reach 2% everythink looks fine.
Are you aware of a published article that also explains this concept using the same method?
I can look for it in my documents but you can also cite this video :)
Prof ..how this equation helps us to find the cutting speed of machine tools?
Dont know what you mean, this equation is not for machining as far as i know. I guess you have to do some literature research
can you share the xls??
I don't understand this step. σy=（A）(B) (n) (C) (m) → σy=（A）(B) (n) ？
At which minute and second
@@hnrwagner 0：13 - 0:20
@@echo115 u just set the other values in the brackets to 1, otherwise you cant calculate A,B & n