I have very minimal experience in subroutines. Kindly let me know why we are using 'beta' in the lines of code below yet it is a parameter(constant). if ( beta .gt. zero ) then call betaDamping3d ( nblock, * beta, dt, strainInc, * stressOld, stressNew, * stateNew(1,i_svd_statusMp), * stateOld(1,i_svd_dampStress), * stateNew(1,i_svd_dampStress) ) end if Thank you.
I need to change the density and thermal expansion coefficient along x direction in ABAQUS. Can it be possible in UMAT ? How to implement this? Help me out.
I am having a plate which made with steel and impact with rigid cylinder. And velocity is given in amplitude form. But I am not able to balance the energy. Kinetic energy is coming double than internal energy.
Dear Sanan, in the previous videos you have given the Velocity Boundary Condition with amplitudes for Reference point in step-1. But in this video you have used the predefined velocity Boundary Condition for the reference point.. what could be the difference that we can find between them... And if we won't give any amplitudes in the Velocity Boundary Condition, the velocity of the impactor is remaining constant in the step-1.. what you could suggest if we want to include the Hertz contact law during the impact loading and get the velocity profile of the impactor as the function of time.
Dear SIr, I'm trying to prepare the model of multiple impact of the composite. The first strike goes well, however I have some issues while importing the output of first strike to second analysis. After submiting the analysis, on packager stage the following message (error) appears: Bad Material definition in element number XXXX instance XXXXXXXXXXXXXX: zero or negative initial dilatational modulus caused by bad material data. Please check your material input and any initial conditions if necessary. Is it caused by subroutine code, or inssuficient material data? I'd like to ask for your help in it. Kind regards
Thanks a lot. It's really a good video for learning Abaqus. You said that you get the VUMAT file from Hashin website. Is it possible to give the address of that website?
Dear sanan, thanks alot for this useful video. I want to use 3d hashin for 3piont bending and model it according to your video. But when i run it, errors LNK2019 AND LNK1120 occurs. Can you help me to solve these errors. Thanks a lot
sir for dynamic explicity also i used the same cohesive surface method , but after applying ,the shape of model is changing ,will u give any suggesion why its happeining like that
Sanan thanks a lot for taking the time out to make this video. I wanted to ask how to determine/calculate the fracture energies (G1+, G1-, G2+, G2-) required by the damage evolution models for ply damage. Are there some standard ATSM procedures to determine them?
these are the fracture energies in particular mode. will be obtained by loading the material in 1 mode only and obtaining load displacement for it. the area under the curve will be its energy. yes ASTM are available sear ch for it.
A lot of thanks. Through looking into your VUMAT script, I am afraid that the formula for matrix tension failure mode is not correct with regard to the 3d hashin failure criteria. "f12Inv" should be multiplied rather divided in the third part of this equation. I know you may just take this for an example to show us how to use VUMAT, but it' s better to correct it for clarity.
Hi. I was working on the drop impact of a T-joint and it can run with my model. However, the model has to run for one month on my laptop. Then I changed to use continuum shell elements with the built-in Hashin criteria.
Dear Sanah, I made all the modifications u mentioned in the video, still I'm getting error due to excessive element distortion in the first increment only. I am stuck with my project and will be grateful if u can help me.
i never said these were the modifications. i said these were methodology errors which should have been avoided. any how you should make your own subroutine.
Actually I'm just a beginner and currently in the learning stage. I am working on an impact analysis problem, using solid element. So the Hashin 3d is to be made by vumat. I don't understand what I'm doing wrong. So I am asking for a little assistance. If it is convenient, can I contact u personally for some guidance? I promise it won't take much time..
Hi Sanan, Thanks for such a nice video of vumat subroutine. I am working on low velocity impact on composite using VUMAT. I go through your video and I made all the changes in vumat subroutine whatever you told in video. I got the error of excessively distorted elements which you also told in your video in the end. Right now I am not able to detect why this error is coming. Could you help me to detect why this error is coming and how to eliminate it. It would be very grateful if you help me out.
Sir could you Please suggest me what parameters should I take if I would write my own subroutine or which parameter should I remove from Hashin subroutine like damping or energy parameter
You are the best. I've just started to learn ABAQUS but I'm not finding any good resource except abaqus documentation. Can you suggest some of the resources with which you started your journey?
Hi Sanan, The author mentioned the subroutine 'eig33Anal: Compute eigen values of a 3x3 symmetric matrix analytically'. What is this subroutine used for? Many thanks.
The best way to do it by learning a basic FORTRAN operation and it's rule... Check out an algorithm from papers and try to implement it without damage. Abaqus provide some readymade subroutine that can be used to practice.
good work. could you make your VUMAT available for people's use?
Thanks@Sanan,
I think they used Puck criterion for matrix tension and compression.
I have very minimal experience in subroutines. Kindly let me know why we are using 'beta' in the lines of code below yet it is a parameter(constant).
if ( beta .gt. zero ) then
call betaDamping3d ( nblock,
* beta, dt, strainInc,
* stressOld, stressNew,
* stateNew(1,i_svd_statusMp),
* stateOld(1,i_svd_dampStress),
* stateNew(1,i_svd_dampStress) )
end if
Thank you.
i think its different from what the puck criteria is.
for damping...also known as beta damping
@Sanan, I hope you got my message.
Thanks a lot sir
I want to ask where is the block responsable for damage evolution
hei what about Damage stabilization? I see you checked the box for activation but don't show the value. thanks
I need to change the density and thermal expansion coefficient along x direction in ABAQUS. Can it be possible in UMAT ? How to implement this? Help me out.
Sir..where did you call the subroutine for Hashin damage 3d?....after orthoElast routine?
I am having a plate which made with steel and impact with rigid cylinder. And velocity is given in amplitude form. But I am not able to balance the energy. Kinetic energy is coming double than internal energy.
Dear Sanan, in the previous videos you have given the Velocity Boundary Condition with amplitudes for Reference point in step-1. But in this video you have used the predefined velocity Boundary Condition for the reference point.. what could be the difference that we can find between them... And if we won't give any amplitudes in the Velocity Boundary Condition, the velocity of the impactor is remaining constant in the step-1.. what you could suggest if we want to include the Hertz contact law during the impact loading and get the velocity profile of the impactor as the function of time.
I have no element distorsion but mt probelm is related to the damage evolution
Whats the [props(11) --> "not used" ] and [beta damping parameter] inVUMAT mean?Need one to one correspondence? Thanks very much!
?hello Sanan, and thank you, modeling laminate by one part and create patition is popssible for this your VUMAT
hello sanan , can you make video on puck failure criterion. it would be much helpful
yes pls Sir sanan. it's really helpful !
Dear SIr, I'm trying to prepare the model of multiple impact of the composite. The first strike goes well, however I have some issues while importing the output of first strike to second analysis. After submiting the analysis, on packager stage the following message (error) appears:
Bad Material definition in element number XXXX instance XXXXXXXXXXXXXX: zero or negative initial dilatational modulus caused by bad material data. Please check your material input and any initial conditions if necessary.
Is it caused by subroutine code, or inssuficient material data? I'd like to ask for your help in it.
Kind regards
How fracture energy introduce in VUMAT
Thanks a lot. It's really a good video for learning Abaqus.
You said that you get the VUMAT file from Hashin website. Is it possible to give the address of that website?
Dear sanan, thanks alot for this useful video. I want to use 3d hashin for 3piont bending and model it according to your video. But when i run it, errors LNK2019 AND LNK1120 occurs. Can you help me to solve these errors.
Thanks a lot
sir
for dynamic explicity also i used the same cohesive surface method , but after applying ,the shape of model is changing ,will u give any suggesion why its happeining like that
How to create impact load on beam of weight 760 from height 300mm
Sanan thanks a lot for taking the time out to make this video. I wanted to ask how to determine/calculate the fracture energies (G1+, G1-, G2+, G2-) required by the damage evolution models for ply damage. Are there some standard ATSM procedures to determine them?
these are the fracture energies in particular mode. will be obtained by loading the material in 1 mode only and obtaining load displacement for it. the area under the curve will be its energy. yes ASTM are available sear ch for it.
thx a lot sanan
also the strength properties (X1+ X1- etc) that we input, are these the yield strengths or ultimate strengths?
yield and ultimate are same for composites :)
Thx man
sir can you do a tutorial how to make a coating layer on metal subtrate like tbc coating on metal
Sir can please tell me how to implement damage evolution equations
very nice video. how did you link the ftn95 with abaqus? it would be wonderfui if you make another video about it
will do it as i got any time.
@@SanaanKhan i personally am looking forward to it.
A lot of thanks. Through looking into your VUMAT script, I am afraid that the formula for matrix tension failure mode is not correct with regard to the 3d hashin failure criteria. "f12Inv" should be multiplied rather divided in the third part of this equation. I know you may just take this for an example to show us how to use VUMAT, but it' s better to correct it for clarity.
phoebe Zhang hello，phoebe，it seems that you are trying to simulate dynamic impact with abaqus? Can you make it?
Hi. I was working on the drop impact of a T-joint and it can run with my model. However, the model has to run for one month on my laptop. Then I changed to use continuum shell elements with the built-in Hashin criteria.
phoebe Zhang hi,I want use abaqus to simulate dynamic impact. Do you have wechat or email?
email address, babygirl0627@hotmail.com
@@wolferi9615 sir i am working on ballistic impact on composite target . is this steps can be used
Dear Sanah,
I made all the modifications u mentioned in the video, still I'm getting error due to excessive element distortion in the first increment only. I am stuck with my project and will be grateful if u can help me.
i never said these were the modifications. i said these were methodology errors which should have been avoided. any how you should make your own subroutine.
Actually I'm just a beginner and currently in the learning stage. I am working on an impact analysis problem, using solid element. So the Hashin 3d is to be made by vumat. I don't understand what I'm doing wrong. So I am asking for a little assistance. If it is convenient, can I contact u personally for some guidance? I promise it won't take much time..
Sir.. it would be easier if I could contact u via email, as per ur convenience..
@@gourabchakraborty9432 i am also getting same error
can u able to resolve it share ur email
Hi Sanan, Thanks for such a nice video of vumat subroutine. I am working on low velocity impact on composite using VUMAT.
I go through your video and I made all the changes in vumat subroutine whatever you told in video. I got the error of excessively distorted elements which you also told in your video in the end. Right now I am not able to detect why this error is coming. Could you help me to detect why this error is coming and how to eliminate it.
It would be very grateful if you help me out.
as i said the algorithm used in the subroutine is erroneous. even i am facing this issue while using it.
Sir could you Please suggest me what parameters should I take if I would write my own subroutine or which parameter should I remove from Hashin subroutine like damping or energy parameter
@@nitinkhandelwal5829 elasticity damage initiation and damage evolution. This will completely defined the behaviour.
@@nitinkhandelwal5829 no need of damping. Evolve the damage slowly
You are the best.
I've just started to learn ABAQUS but I'm not finding any good resource except abaqus documentation. Can you suggest some of the resources with which you started your journey?
good knowledge of FEM
Could you please tell me if geometrical nonlinearity is considered?
No
Hi Sanan,
The author mentioned the subroutine 'eig33Anal: Compute eigen values of a 3x3 symmetric matrix analytically'. What is this subroutine used for?
Many thanks.
to curtail any high frequency oscillations occurring due to impact. it can also delete the element.
Thanks Sanan
Sir, How do I learn VUMAT?...and can you pls provide the material or souce for it?..
The best way to do it by learning a basic FORTRAN operation and it's rule... Check out an algorithm from papers and try to implement it without damage. Abaqus provide some readymade subroutine that can be used to practice.
Dear Sanan , is there a video before this? please give the descriptions of geometry and dimensions of model ?
thank you
please see the link in the description of the video.
thank you sir
Plz sir make a new video on compression tesion and 3 point bending test for my types new learner
hello sir, i am also working on impact on composites and writing VUMAT codes can you please help me ..can you share your mail ..i have some doubts.
Very Good
great
can you add your email to contact you for more information
thanks .Sanan
Whats the [props(11) --> "not used" ] and [beta damping parameter] inVUMAT mean?Thanks very much!
What is the dimension? mm,Mpa? or GPa? Thanks!
ignore it.