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.

Whats the [props(11) --> "not used" ] and [beta damping parameter] inVUMAT mean?Need one to one correspondence? Thanks very much!

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.

Thanks a lot sir I want to ask where is the block responsable for damage evolution

Sir..where did you call the subroutine for Hashin damage 3d?....after orthoElast routine?

hei what about Damage stabilization? I see you checked the box for activation but don't show the value. thanks

good work. could you make your VUMAT available for people's use?

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

?hello Sanan, and thank you, modeling laminate by one part and create patition is popssible for this your VUMAT

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

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?

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

Very Good

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.

great

Sir can please tell me how to implement damage evolution equations

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?

@SanaanKhan

7 жыл бұрын

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.

@nooruddinsadruddin9887

7 жыл бұрын

thx a lot sanan

@nooruddinsadruddin9887

7 жыл бұрын

also the strength properties (X1+ X1- etc) that we input, are these the yield strengths or ultimate strengths?

@SanaanKhan

7 жыл бұрын

yield and ultimate are same for composites :)

@nooruddinsadruddin9887

7 жыл бұрын

Thx man

sir can you do a tutorial how to make a coating layer on metal subtrate like tbc coating on metal

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?

@SanaanKhan

6 жыл бұрын

good knowledge of FEM

Thanks@Sanan, I think they used Puck criterion for matrix tension and compression.

@belatei

7 жыл бұрын

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.

@SanaanKhan

7 жыл бұрын

i think its different from what the puck criteria is.

@SanaanKhan

7 жыл бұрын

for damping...also known as beta damping

@belatei

7 жыл бұрын

@Sanan, I hope you got my message.

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.

@SanaanKhan

7 жыл бұрын

to curtail any high frequency oscillations occurring due to impact. it can also delete the element.

@yuexiangwang6765

7 жыл бұрын

Thanks Sanan

How to create impact load on beam of weight 760 from height 300mm

How fracture energy introduce in VUMAT

I have no element distorsion but mt probelm is related to the damage evolution

very nice video. how did you link the ftn95 with abaqus? it would be wonderfui if you make another video about it

@SanaanKhan

5 жыл бұрын

will do it as i got any time.

@sehatatlier291

5 жыл бұрын

@@SanaanKhan i personally am looking forward to it.

thanks .Sanan

Whats the [props(11) --> "not used" ] and [beta damping parameter] inVUMAT mean?Thanks very much!

@charles3079

7 жыл бұрын

What is the dimension? mm,Mpa? or GPa? Thanks!

@SanaanKhan

7 жыл бұрын

ignore it.

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.

@SanaanKhan

5 жыл бұрын

as i said the algorithm used in the subroutine is erroneous. even i am facing this issue while using it.

@nitinkhandelwal5829

5 жыл бұрын

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

@SanaanKhan

5 жыл бұрын

@@nitinkhandelwal5829 elasticity damage initiation and damage evolution. This will completely defined the behaviour.

@SanaanKhan

5 жыл бұрын

@@nitinkhandelwal5829 no need of damping. Evolve the damage slowly

hello sanan , can you make video on puck failure criterion. it would be much helpful

@muhammadamirulhakimbinmoha3084

5 жыл бұрын

yes pls Sir sanan. it's really helpful !

Could you please tell me if geometrical nonlinearity is considered?

@SanaanKhan

3 жыл бұрын

No

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.

@SanaanKhan

5 жыл бұрын

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.

@gourabchakraborty9432

5 жыл бұрын

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..

@gourabchakraborty9432

5 жыл бұрын

Sir.. it would be easier if I could contact u via email, as per ur convenience..

@sukhoimk3036

5 жыл бұрын

@@gourabchakraborty9432 i am also getting same error can u able to resolve it share ur email

Sir, How do I learn VUMAT?...and can you pls provide the material or souce for it?..

@SanaanKhan

3 жыл бұрын

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.

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.

@wolferi9615

6 жыл бұрын

phoebe Zhang hello，phoebe，it seems that you are trying to simulate dynamic impact with abaqus? Can you make it?

@phoebezhang5579

6 жыл бұрын

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.

@wolferi9615

6 жыл бұрын

phoebe Zhang hi,I want use abaqus to simulate dynamic impact. Do you have wechat or email?

@phoebezhang5579

6 жыл бұрын

email address, babygirl0627@hotmail.com

@nidhinkrishna734

5 жыл бұрын

@@wolferi9615 sir i am working on ballistic impact on composite target . is this steps can be used

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.

Dear Sanan , is there a video before this? please give the descriptions of geometry and dimensions of model ? thank you

@SanaanKhan

7 жыл бұрын

please see the link in the description of the video.

@lalkrishna4518

7 жыл бұрын

thank you sir

can you add your email to contact you for more information