Dear Ameen, I had trouble starting simulation after following instructions because it was ending with 2 errors. Luckily i was able to solve them. Catch was in 17:48 where both Boundary IDS were =0. After changing them to 1 and 2 (respectively) simulation was able to run without errors. Thanks for the instructional video
Hi Mr Ameen, Allow me to tell you this video is really good! However you can introduce tricky comments like the restriction of the material failure you used is only valid for traction and work in this case because we do not have compressive stress state, otherwise we require a triaxility failure criteria. And the reason why using linear plasticity we'll never be able to capture necking effect.
Yes, you are right. Thanks for your insightful comments. This is only a basic tutorial, that's why I didn't go deep into the theory! I will make a video for more detailed damage and fracture modelling. :D
hi Ameen Sir, actually i had experimental true stress strain data , so can it be used to define stress strain curve in material chord and can we use displacement vs time data obtained from experiment to define displacement curve instead velocity curve.
Hi Solomon, what you ask is very detailed. I am planning for these type of detailed tutorials in the future after my channel grows and get more subscribers. So please like my videos and share my channel to your colleagues. For the time being, if you need urgent or specific help, drop your email here. I will contact you and will see what I can do.
I don't have any tutorials on that. But if you follow my first few tutorials in my LSDYNA BASIC TUTORIALS playlist, you will be able to do it yourself..
Thank you, Amin, for this video, when you defined the stress-strain curve, did you consider the elastic region on the curve started from the plastic strain? Thanks
With MAT024, you do not need to define the elastic region because you already put the Young's modulus. The curve used in MAT024 is plastic stress vs plastic strain curve. Check this video for more about this material: ua-cam.com/video/J5Qjj_9Sot0/v-deo.html
thank you Dr Ameen Topa, i have few questions regarding tensile testing using lsdyna: 1.) is this tensile testing done using explicit time integration? 2.) where do we apply time scaling and mass scaling for explicit time integration? 3.) can u recommend where i can learn how to do implicit time integration?
Dear Rey, 1) Yes, it is using explicit solver. Since this is a small model, using explicit will not take long time. 2) For time scaling, you simply increase the load or displacement rate by adjusting the curve. For mass scaling, you can either use DT2MS in CONTROL TIMESTEP to limit the minimum timestep or you can manually increase the density of each material in your model. You can check out my tutorial here to see how I did the last method of mass scaling: LS-DYNA TUTORIAL 15: Shaft Torsion with Mass scaling, Ductile and Brittle Failure 3) You can check out my tutorials: LS-DYNA TUTORIAL 4: Compression Load on Solid Cylinder LS-DYNA TUTORIAL 12: Static and Dynamic Axial Tube Crush You can also check the examples here: www.dynaexamples.com/implicit
Thank you very much Dr Topa for all your good professional work. I would like to know if there is available website for Stainless steel and mild steel just similar to Varmint al's engineering page. Thank you.
You only need a material properties at elevated temperature. Throughout the tensile test, the temperature will be almost constant, thus you can assume that it is a pure structural simulation.
@@AmeenTopa thank you Ameen, how to find out material properties at 200, 250 deg like tangent, elastic modulus, density etc..for material like AZ31B magnesium alloys..pls suggest.
can you explain why the plastic strain increases at the initial time? I think plastic strain should be increased after the yielding point. but in your video, plastic strain is increased at the initial time(t=1))
@@barbus6305 Yes, you are correct. Sig X = Sig VM in this case. Sorry, I was confused with another tutorial. The reason simply because DT = 1 is too big so the output intervals are big as well.. If you put DT = 0.01 and run the simulation, you will get more accurate results.
Technically, there is no much different in the outcome. The difference is when you are making the file. When you define any command, let say material properties, after you put the values, you click on accept. Now, if you click Add, all the values will go back to default, but if you click newID, it will give you new ID, but all the values are the same. This is helpful in situation like if You have two materials, all the properties are the same except one value (maybe density), so now you defined first material, click on accept. Then you click on NewId, change the density, then click on accept. So, you don't have to input the properties of the second material since it is there already. I hope you understand what I mean.
Hi Ameen, Thanks for the tutorial! Great help! I am wondering if we can directly plot engineering stress/strain and true stress/strain? if only v-m stress how can it convert to true stress by any chance? and the second question is how we adjust the result if the Force vs Time plot has a large oscillation?
For the first question, you can directly plot the true stress strain curve by extracting the stress and strain from a single element. It may not be close to the value you find experimentally because that's the mean value of all the points in the specimen. You cannot directly plot engineering stress strain because the software doesn't know how to get the engineering stress. All the values such as stress and strain are calculated instantaneously at each elements. For the oscillations, you can use the filter option in the plot window.
The shape or geometry model was created with SOLIDWORKS and you can get download it from the GrabCAD website. It is a shape or geometry, and we cannot do finite element simulations on shapes or geometry models. That's why I deleted it. I needed it only to create the mesh. After the mesh is created, it has no use in the simulations.
@@AmeenTopa how can i create tensile test model with constant geometry and solid not shell. Moreover, how can i learn LS-dyna in more details and effectively from basic to advance? Thank you
@@bilalrana9543 After you created the shell elements as I did in my tutorial, go to Element Generation, Solid, by Shell Drag. With this tool, you can create the solid elements. LS-DYNA is not an easy software to learn because the LS-Prepost interface is not user friendly. You need to have a mentor in order to speed up the process of learning. You can learn by yourself but it will take some years. With that being said, I am available for online consultation if you need help to model a specific problem. However, there will be charges, of course.
You can run a simulation with no failure first, then plot the stress strain curve. Then compare the numerical graph with the experimental curve. From there, you can estimate the failure strain. For this, you need to have the experimental values until the rupture point. If you have the data only until necking, then I do not know of a method to predict the failure strain.
@@AmeenTopa Thank you very much for the reply! Now its clear that I need to have full raw data from experiment, so looks like I misunderstood my teacher, thank you again
dear Ameen, I would ask you how to make a calibration of a tensile metal strip in MAT-024, I have made many experimental tests and have obtained a force-strain curves. I would like to make a calibration to them. Is it possible with the Varmintal website? Thank you
Dear Nabli, This depends if the material grade is avaiable in Varmintal's website. Also, the data there doesn't take into consideration the strain rate effects.
The same model in this video. You can go to Mesh, Element Generation, choose the solid option. Then, create solid by Shell_Drag. input your thickness and the number of segment (how many layers you want), hit Create, then accept and there you go! You created a solid model. Don't forget to update the boundary conditions (the Node Set)
Please check my latest video at ua-cam.com/video/llNL8Kb1pQg/v-deo.html Now, that I've done this video for you. You have to like all my videos, and tell at least 10 of your friends to subscribe my channel and like all my videos. XD
Thank for your video. Could you recommend me some intructions for my problem: i want to simulate a test test , i want to get as outputs the curvv force displacement? how can i get it? i've tried to toogle some options (NODFOR - Nodal force groups and NODOUT - Nodal Displacement) in the ascii module of database. I activated also the nodal force group card in the database module. Unfortunatly, i did'nt get what i want
First of all, we cannot get the force vs displacement directly from the LS-PREPOST. First, we need to get force vs time then displacement Vs time and cross plot them. How to get the force vs time? You can try nodout or bndout in acsii options.
Somehow UA-cam doesn't allow links. You can search the following videos: Post Processing Tutorial (with LS-Prepost) LS-DYNA TUTORIAL 9: Tensile Test with Solid Elements and Variable Thickness Shells
Hi Ameen, thanks for the tutorial. but i get different results, the specimen breaks at two points not just at one point like in your results. i have tried to follow all the steps two times but still it breaks at two points at the same time. what can you suggest?
Actually, it doesn't make since that the material is ruptured in two points. According to material mechanics, it should break only in one point. There might be a mistake in one of the steps when you were making the file.
Does LS Dyna geometry use MMGS or IPS unit system? (For example, if I convert an IPS solidworks geom to IGES and export to hyperworks, hyperworks takes same magnitude of geometry length/width but in mm. So I always had to convert IPS to MMGS in solidworks and then export it as IGES) I do this because I am more comfortable with all material properties in MMGS units than IPS. Is this the same case with LS-Dyna too?
Is it advisable to say, i define curve for a certain material (304 SSteel ), say the curve named Displacement, if i want define another curve can i give the same name (304 SSteel ) and ID and assign say new define curve say Stress Strain Curve.
Dear Ameen Topa. I have been practicing your tutorials. I have an issue while loading the .csv file that is not getting a similar plot curve. Instead, I'm getting some weird curve. I have downloaded the same file and same XY data. But got weird curve. Any suggestions?
@@AmeenTopa so I'm practising the second tutorial on Tensile test. I downloaded the file and then uploaded in CSV form as said in video. I didn't get the exact curve as in the video . I got different curve . My " X " values are not increased constantly. Instead values varied ( Increased then decreased again increased )but "Y " has constant increased values. Due to this my stress vs strain curve came out in a zig - zag way. It's the mistake of the values. If you want to understand exactly. You just download the same folder and upload the csv file. You will also get this weird graph.
Good day Dr Topa, I realise that my model does not animate, not sure my mass or excitation velocity are very or my computer is an issue. May be my units. Can you just highlight for me.
DEFINE_CURVE doesn't read XY data in scientific notation but instead reads in decimal notation due to which it is not able to define the right curve. How to fix this?
@@AmeenTopa I am also facing the same issue. I am importing the csv file, but the curve is not proper, and the data is in decimal format can you please help me with it.
Firstly, I would like to thanks to you but I have an issue.I calculated plastic strain but when I checked the v-m stress, it is not calculated I do not know why, Sir.
By default, for shell elements, the plastic strain is not displayed in the results. To view that, check out this link: www.dynasupport.com/howtos/element/shell-output
Hi Ameen, I executed same as the tutorial. In the 2nd iteration I used *load in place of *boundary_prescribed motion set, material is deformed but failure has not occurred. What corrections should I do?
@@roublard17 maybe you are using Rigid material or there is no forces on the car. I can't tell for sure. There is insufficient information for a conclusive answer.
Dear Amin Sir, I watched your videos regarding LS-Dyna. Very helpful. could you explain the term "tensile stress cut-off" in MAT 163? kindly provide the hint.
Dear Patil, I have used this material model before. Here is my research article for your reference: downloads.hindawi.com/journals/mse/2014/292647.pdf Also, you may refer to the following paper: libres.uncg.edu/ir/uncc/f/Bi_uncc_0694D_10301.pdf Sincerely, Ameen NOT AMIN
Hello Ameen, Thank you for sharing the tutorial on tensile test. I did as you mentioned in your tutorial but when I check my result in Post>Fringe Component> Effective Plastic Strain, it shows zero throughout whereas for other parameters I get the values. I even tried to define "Database_Extent Binary and selected STRFLG =1. Still it shows zero. Your advice will be highly appreciated.
@@AmeenTopa Thank you. I will check this link. But in your tutorial for output you just define Binary_d3plot and control_termination and get the effective plastic strain. If you don't mind can you share with me the keyfile of this tutorial?
@@saifshahabuddin6519 This tutorial is dated back years ago. I don't have the file anymore unfortunately. Are you using same material model as in the video?
@@AmeenTopa Thank you for your reply. Yes I understand this tutorial was uploaded way back. I used the same material model i.e MAT_Piecewise_Linear_Plasticity.model.
@@saifshahabuddin6519 hmm, I am not sure. You may try to with higher element formulation (fully integrated shell) It might be the problem with yours solver. I am using double precision solver.
Dear Ameen sir, is the yield stress of pure aluminium SIGY = 13 Mpa? so that in Gpa units it becomes 0.0133 GPa as per tutorial. Please confirm sir. Thank you.
Hy i am new to Ls Dyna . i follow your above tutorial and the problem i faced is that whem I run the simulation, it terminated. I will be thankfull. Kind Regards Rab Nawax
Hello mr Ameen, I would like to know if you can do a tutorial of importing an assembly and mesh it and simulate it, also I would like to know if it is possible to contact you personally. Thanks
To make the input file you need LS Prepost which is free to download from LSTC website. You can run the code on other solvers for example ANSYS solver.
Well although LS Dyna is such a powerful and amazing software but still compared to the ANSYS Structural GUI, it is much more cumbersome to use, just as an example, how difficult it is to tell the software that a particular node set has to be constrained and given certain degrees of freedom and boundary conditions. ANSYS Workbench GUI is the best.
Each software has its pros and cons. Although ANSYS Workbench is very user-friendly, it cannot do the simulation of complicated problems. Proof: just look into the numerical simulations done in scientific journals. Even though LS-DYNA is not very user-friendly, it is more commonly used compared to ANSYS Workbench.
@@AmeenTopa Perhaps the best would be to use the combination of both i.e. ANSYS-LS Dyna, Where one can from the user friendly characteristics of ANSYS Workbench GUI as well as its Vast Material Library (which perhaps is missing in LS Dyna) and the power of LS Dyna.
Yes ANSYS has a vast library of predefined material properties, like you can just choose your part to be structural steel A36 or aluminum alloy AA6061. But LS-DYNA has more options with regards to material models: you have Elastic model, Viscoelastic, Johnson Cook, Bilinear Model, Piecewise Plasticity Model...etc. For a more friendly-user interface, you can try Oasys Software Suite.
İf you know that Can you answer the question? İs knowledge of varmintal webpage reliable about license right? Because I do not use information that no license right. İ wanna ask you Thank you. Have a good day
You can contact the owner of the website. If you are lucky, he will reply. I don't really understand what do you mean about the license. If you mean copyright, then I think no problem to use the data in the website provided that you give proper referencing. Data is published on an open domain (public) websites are accepted in most scientific journals, but don't forget to cite.
Dear Ameen, Could you please make a tutorial to define different Boundary Condition> I'm looking everywhere for someone who could explain how to do with EM Solver, I want to put a potential difference on two ends of a copper mesh. I have a material property like Temperature dependent Conductivity and Stress strain data of Elemental Cu. it's been a week now and my stress is increasing every sleepless night. I hope you reply.
You are most welcome. Please do follow my channel and share my videos with your colleagues. There are other website that I usually refer to as such: www.dynamore.de/en and www.dynaexamples.com You can check: www.lancemore.jp/ for awesome samples of LS-DYNA simulations.
@@AmeenTopa Bos nak tanya sikit. Saya guna model SDOF base excitation. Untuk plate bawah, saya define curve letak acceleration (experiment), tapi bila dah abes simulate tak jadi, plate bawah tak bergerak langsung padahal dah assign acceleration. Agak2 apa masalahnya. Tenkiu
@@muhammadazhar3572 rigid plate? Maybe you are fixing the rigid material. Also, check the units of the acceleration and the units in your simulation. Make sure it is consistent. Are you using m, s, kg or mm, ms, kg, or mm, s, tonne.
Dear Ameen,
I had trouble starting simulation after following instructions because it was ending with 2 errors.
Luckily i was able to solve them.
Catch was in 17:48 where both Boundary IDS were =0. After changing them to 1 and 2 (respectively) simulation was able to run without errors.
Thanks for the instructional video
Good to know your managed to solve it
Good job, that material property database is very helpful. Thanks.
I am glad my video was helpful. Make sure to share it so others can benefit as well. 😁
Marvelous explanação, Master Ameen, I hope to learn each day more, thanks a lot
You are welcome. Please share my videos if you find them useful!
Keep it up, amazing explanations. Thank you and keep uploading
Thanks. Please share my videos so more people can learn.
You are too good man..thanks for the video .. your knowledge is exceptional..thanks
My pleasure! please share my videos so more can benefit!
@@AmeenTopa Sure..no worries
Hi Mr Ameen, Allow me to tell you this video is really good! However you can introduce tricky comments like the restriction of the material failure you used is only valid for traction and work in this case because we do not have compressive stress state, otherwise we require a triaxility failure criteria. And the reason why using linear plasticity we'll never be able to capture necking effect.
Yes, you are right. Thanks for your insightful comments. This is only a basic tutorial, that's why I didn't go deep into the theory! I will make a video for more detailed damage and fracture modelling. :D
Great work !!! Thanks a lot for posting
My pleasure! Please share my channel so it can benefit more people! :)
Link to download LS-DYNA:
getintopc.com/softwares/simulators/ls-dyna-free-download/
hi Ameen Sir, actually i had experimental true stress strain data , so can it be used to define stress strain curve in material chord and can we use displacement vs time data obtained from experiment to define displacement curve instead velocity curve.
Yeah sure. Displacement Vs time can be used as well.
thanks for this tutorial! Dear Ameen Topa; how do you trial crash girder beam against over height vehicle collision
Hi Solomon, what you ask is very detailed. I am planning for these type of detailed tutorials in the future after my channel grows and get more subscribers. So please like my videos and share my channel to your colleagues.
For the time being, if you need urgent or specific help, drop your email here. I will contact you and will see what I can do.
Do you have a step by step tutorial to test on Railway sleeper for a beginner?
I don't have any tutorials on that. But if you follow my first few tutorials in my LSDYNA BASIC TUTORIALS playlist, you will be able to do it yourself..
Thank you, Amin, for this video, when you defined the stress-strain curve, did you consider the elastic region on the curve started from the plastic strain? Thanks
With MAT024, you do not need to define the elastic region because you already put the Young's modulus.
The curve used in MAT024 is plastic stress vs plastic strain curve.
Check this video for more about this material:
ua-cam.com/video/J5Qjj_9Sot0/v-deo.html
hello sir, i tried the same simulation by changing material to brass, my specimen not breaking but elongating, any suggestion pls
Excellent tutorial.
Many thanks! I hope you learned something new! :D
thank you Dr Ameen Topa, i have few questions regarding tensile testing using lsdyna:
1.) is this tensile testing done using explicit time integration?
2.) where do we apply time scaling and mass scaling for explicit time integration?
3.) can u recommend where i can learn how to do implicit time integration?
Dear Rey,
1) Yes, it is using explicit solver. Since this is a small model, using explicit will not take long time.
2) For time scaling, you simply increase the load or displacement rate by adjusting the curve. For mass scaling, you can either use DT2MS in CONTROL TIMESTEP to limit the minimum timestep or you can manually increase the density of each material in your model.
You can check out my tutorial here to see how I did the last method of mass scaling:
LS-DYNA TUTORIAL 15: Shaft Torsion with Mass scaling, Ductile and Brittle Failure
3) You can check out my tutorials:
LS-DYNA TUTORIAL 4: Compression Load on Solid Cylinder
LS-DYNA TUTORIAL 12: Static and Dynamic Axial Tube Crush
You can also check the examples here:
www.dynaexamples.com/implicit
Thank you very much Dr Topa for all your good professional work. I would like to know if there is available website for Stainless steel and mild steel just similar to Varmint al's engineering page. Thank you.
You are welcome. Sorry I don't know any other websites. You need to know the grade of the steel and search in the published articles.
@@AmeenTopa Thank you Dr Topa.
thank you Ameen, may i know different cards that are essential to run simulation of high temperature tensile test at about 200 deg
You only need a material properties at elevated temperature. Throughout the tensile test, the temperature will be almost constant, thus you can assume that it is a pure structural simulation.
@@AmeenTopa thank you, pls suggest mandatory cards to be used
@@vbalaji_griet123 As I mentioned, you only need to use the material properties at 200 degrees, that's all.
@@AmeenTopa thank you Ameen, how to find out material properties at 200, 250 deg like tangent, elastic modulus, density etc..for material like AZ31B magnesium alloys..pls suggest.
@@vbalaji_griet123 You can search in the open literature: journal articles and PhD theses.
can you explain why the plastic strain increases at the initial time?
I think plastic strain should be increased after the yielding point.
but in your video, plastic strain is increased at the initial time(t=1))
That's a valid question. I have another tutorial on the tensile test, I think if you watch that, you will know the answer. 😁
Hello, Ameen. Why is the yield strength in the initial data 1.3362E-2 GPa, and on the Stress-Strain graph its value is approximately 4.00E-2 GPa?
Because I plotted the von Mises equivalent stress, not the stress in the x direction.
@@AmeenTopa In this case, Stress von Mises is no different from X-Stress.
@@barbus6305 Yes, you are correct. Sig X = Sig VM in this case. Sorry, I was confused with another tutorial.
The reason simply because DT = 1 is too big so the output intervals are big as well.. If you put DT = 0.01 and run the simulation, you will get more accurate results.
@@AmeenTopa, Thank you
thank you, can you please tell me how to make tensile samples using LS DYNA PREPOST
I have a video on this. Check my playlist: "MESH IT WITH PREPOST!"
Thank you Mr. Topa
You are welcome. Please share my videos to spread the knowledge.
In your video, at boundry_prescribe_motion_set you have shown to click Add. What is different between Add and NewID?
Technically, there is no much different in the outcome. The difference is when you are making the file.
When you define any command, let say material properties, after you put the values, you click on accept.
Now, if you click Add, all the values will go back to default, but if you click newID, it will give you new ID, but all the values are the same.
This is helpful in situation like if
You have two materials, all the properties are the same except one value (maybe density), so now you defined first material, click on accept. Then you click on NewId, change the density, then click on accept. So, you don't have to input the properties of the second material since it is there already.
I hope you understand what I mean.
Hi Ameen, Thanks for the tutorial! Great help! I am wondering if we can directly plot engineering stress/strain and true stress/strain? if only v-m stress how can it convert to true stress by any chance? and the second question is how we adjust the result if the Force vs Time plot has a large oscillation?
For the first question, you can directly plot the true stress strain curve by extracting the stress and strain from a single element. It may not be close to the value you find experimentally because that's the mean value of all the points in the specimen.
You cannot directly plot engineering stress strain because the software doesn't know how to get the engineering stress. All the values such as stress and strain are calculated instantaneously at each elements.
For the oscillations, you can use the filter option in the plot window.
Hi Ameen, how did you create that model for tensile test and why did you delete a portion after meshing in the start?
The shape or geometry model was created with SOLIDWORKS and you can get download it from the GrabCAD website.
It is a shape or geometry, and we cannot do finite element simulations on shapes or geometry models. That's why I deleted it. I needed it only to create the mesh. After the mesh is created, it has no use in the simulations.
@@AmeenTopa how can i create tensile test model with constant geometry and solid not shell. Moreover, how can i learn LS-dyna in more details and effectively from basic to advance? Thank you
@@bilalrana9543 After you created the shell elements as I did in my tutorial, go to Element Generation, Solid, by Shell Drag. With this tool, you can create the solid elements.
LS-DYNA is not an easy software to learn because the LS-Prepost interface is not user friendly. You need to have a mentor in order to speed up the process of learning. You can learn by yourself but it will take some years.
With that being said, I am available for online consultation if you need help to model a specific problem. However, there will be charges, of course.
@@AmeenTopa i am interested in learning and want to familiarize myself to Prepost interface. how can contact you?
@bilalrana9543 you can reach me personally on Facebook, LinkedIn or you can email my team (cae-works@outlook.com)
Hi Ameen, could you give a hint how to find (predict) failure strain with tensile test simulation if I have only raw data finishing at necking point?
You can run a simulation with no failure first, then plot the stress strain curve. Then compare the numerical graph with the experimental curve. From there, you can estimate the failure strain.
For this, you need to have the experimental values until the rupture point. If you have the data only until necking, then I do not know of a method to predict the failure strain.
@@AmeenTopa Thank you very much for the reply! Now its clear that I need to have full raw data from experiment, so looks like I misunderstood my teacher, thank you again
@@piotrpawlak8376 You are welcome. I am glad it's clear now.
dear Ameen,
I would ask you how to make a calibration of a tensile metal strip in MAT-024, I have made many experimental tests and have obtained a force-strain curves. I would like to make a calibration to them. Is it possible with the Varmintal website?
Thank you
Dear Nabli,
This depends if the material grade is avaiable in Varmintal's website. Also, the data there doesn't take into consideration the strain rate effects.
Extremely informative. Please could you make a video for solid model tensile test.
The same model in this video. You can go to Mesh, Element Generation, choose the solid option. Then, create solid by Shell_Drag. input your thickness and the number of segment (how many layers you want),
hit Create, then accept and there you go! You created a solid model.
Don't forget to update the boundary conditions (the Node Set)
Please check my latest video at
ua-cam.com/video/llNL8Kb1pQg/v-deo.html
Now, that I've done this video for you. You have to like all my videos, and tell at least 10 of your friends to subscribe my channel and like all my videos. XD
@@AmeenTopa sure I will give a thumbs up and tell everyone
Hi sir, small query, why tensile specimen not breaking at the middle, any specific cause? can you pls clarify
The load was not applied at the correct rate. This simulation is not quasi static.
Thank for your video. Could you recommend me some intructions for my problem: i want to simulate a test test , i want to get as outputs the curvv force displacement? how can i get it? i've tried to toogle some options (NODFOR - Nodal force groups and NODOUT - Nodal Displacement) in the ascii module of database. I activated also the nodal force group card in the database module. Unfortunatly, i did'nt get what i want
First of all, we cannot get the force vs displacement directly from the LS-PREPOST. First, we need to get force vs time then displacement Vs time and cross plot them.
How to get the force vs time? You can try nodout or bndout in acsii options.
I have another tutorial on tesile test, check that one out. Also, check my post processing tutorial.
@@AmeenTopa could you please attached the link of these tutorials, thank you for your rapide reply
I m trying to get the experimental force measured by the test
Somehow UA-cam doesn't allow links. You can search the following videos:
Post Processing Tutorial (with LS-Prepost)
LS-DYNA TUTORIAL 9: Tensile Test with Solid Elements and Variable Thickness Shells
Hi Ameen, thanks for the tutorial. but i get different results, the specimen breaks at two points not just at one point like in your results. i have tried to follow all the steps two times but still it breaks at two points at the same time. what can you suggest?
Actually, it doesn't make since that the material is ruptured in two points. According to material mechanics, it should break only in one point. There might be a mistake in one of the steps when you were making the file.
Does LS Dyna geometry use MMGS or IPS unit system?
(For example, if I convert an IPS solidworks geom to IGES and export to hyperworks, hyperworks takes same magnitude of geometry length/width but in mm. So I always had to convert IPS to MMGS in solidworks and then export it as IGES)
I do this because I am more comfortable with all material properties in MMGS units than IPS.
Is this the same case with LS-Dyna too?
LS DYNA can use both unit systems...depends on the user.
www.dynasupport.com/howtos/general/consistent-units
Is it advisable to say, i define curve for a certain material (304 SSteel ), say the curve named Displacement, if i want define another curve can i give the same name (304 SSteel ) and ID and assign say new define curve say Stress Strain Curve.
my point is i also want to link stress strain curve like i did to link displacement to material.
Dear Kerileng,
Check out this video where I defined more than one curve and link them to the material.
ua-cam.com/video/aDTQXOYYmAg/v-deo.html
Dear Ameen Topa. I have been practicing your tutorials. I have an issue while loading the .csv file that is not getting a similar plot curve. Instead, I'm getting some weird curve. I have downloaded the same file and same XY data. But got weird curve. Any suggestions?
What do you mean by weird curve?
I request elaboration.
@@AmeenTopa so I'm practising the second tutorial on Tensile test. I downloaded the file and then uploaded in CSV form as said in video. I didn't get the exact curve as in the video . I got different curve . My " X " values are not increased constantly. Instead values varied ( Increased then decreased again increased )but "Y " has constant increased values. Due to this my stress vs strain curve came out in a zig - zag way. It's the mistake of the values. If you want to understand exactly. You just download the same folder and upload the csv file. You will also get this weird graph.
Can you read in the comments section? Others have faced a problem with the curve and it was resolved.
Good day Dr Topa, I realise that my model does not animate, not sure my mass or excitation velocity are very or my computer is an issue. May be my units. Can you just highlight for me.
It could be that you didn't put appropriate values of DT in database_d3plot and ENDTIME in control termination.
@@AmeenTopa Ohk, Thanks let me re-check.
DEFINE_CURVE doesn't read XY data in scientific notation but instead reads in decimal notation due to which it is not able to define the right curve. How to fix this?
If you mean exponential form like (1.0e5) then read xy should support that formatting..
@@AmeenTopa I am also facing the same issue. I am importing the csv file, but the curve is not proper, and the data is in decimal format can you please help me with it.
@@MohanSriram-d1m change the number format with excel then save the file as .csv
Firstly, I would like to thanks to you but I have an issue.I calculated plastic strain but when I checked the v-m stress, it is not calculated I do not know why, Sir.
By default, for shell elements, the plastic strain is not displayed in the results. To view that, check out this link:
www.dynasupport.com/howtos/element/shell-output
Hi Ameen, I executed same as the tutorial.
In the 2nd iteration I used *load in place of *boundary_prescribed motion set, material is deformed but failure has not occurred. What corrections should I do?
Hi Kumar. This means that the load is not enough to break the specimen. Try increasing it.
Hi Ameen, thank you very much for your reply. I increased but its not failing.
Chethankmr27@gmail.com this is my e-mail Id.
Please drop a empty mail, I'll send the key file so that you can correct my mistakes.
Can this exact steps be used in ur crash simulation to output von mises and tresca? I mesh every car and continue like u did with this component ?
Yes. The steps are the same.
@@AmeenTopa thing is automatic mesher wont let me select the car
This is because the car parts are already a finite element part. They are meshed already so no need to create the mesh.
@@AmeenTopa but how come that when i simulate , and when i wanna see von mises stress, i see all the car in blue ? Like there is 0 stress
@@roublard17 maybe you are using Rigid material or there is no forces on the car. I can't tell for sure. There is insufficient information for a conclusive answer.
Dear Amin Sir,
I watched your videos regarding LS-Dyna. Very helpful. could you explain the term "tensile stress cut-off" in MAT 163? kindly provide the hint.
Dear Patil,
I have used this material model before. Here is my research article for your reference:
downloads.hindawi.com/journals/mse/2014/292647.pdf
Also, you may refer to the following paper:
libres.uncg.edu/ir/uncc/f/Bi_uncc_0694D_10301.pdf
Sincerely,
Ameen NOT AMIN
Hello Ameen, Thank you for sharing the tutorial on tensile test. I did as you mentioned in your tutorial but when I check my result in Post>Fringe Component> Effective Plastic Strain, it shows zero throughout whereas for other parameters I get the values. I even tried to define "Database_Extent Binary and selected STRFLG =1. Still it shows zero. Your advice will be highly appreciated.
For more details, you can check here:
www.dynasupport.com/howtos/element/shell-strain
@@AmeenTopa Thank you. I will check this link. But in your tutorial for output you just define Binary_d3plot and control_termination and get the effective plastic strain. If you don't mind can you share with me the keyfile of this tutorial?
@@saifshahabuddin6519 This tutorial is dated back years ago. I don't have the file anymore unfortunately. Are you using same material model as in the video?
@@AmeenTopa Thank you for your reply. Yes I understand this tutorial was uploaded way back. I used the same material model i.e MAT_Piecewise_Linear_Plasticity.model.
@@saifshahabuddin6519 hmm, I am not sure. You may try to with higher element formulation (fully integrated shell)
It might be the problem with yours solver. I am using double precision solver.
Thank you so much for this helpful viddo!!
You are so welcome! please support my channel grow (more subscribers) so I can post more free tutorials!!!
@@AmeenTopa Subscribed!!
@@min2MAXdances thanks a lot!!!!!
I have run my simulation for 100ms. I want to extend it to 200ms but I do not want to repeat previous 100ms. Is there a way? Thanks in advance
You can check my tutorials on implicit simulation and mass scaling. :D
Hello Sir, Is there a way to export a meshed part from ABAQUS to LS Dyna?
Dear Ajay,
Sorry I am not able to help you with this. I have never used ABAQUS.
Thanks to your video, i followed it step by step, but the fail i made doesn't occur in the same place like you, that is normal ?
Yes. It might be that you are using different version of LS DYNA MANAGER.
Hi Dr Topa,thank you very much for the video. The Varmintal website is currently not accessible. Do you have any insight why? :) THanks. Jacky
Hi, it is working fine with me,
www.varmintal.com/aengr.htm
I will upload the file I used in share the link in the subscription.
drive.google.com/open?id=1cDZk9hA6dAORl6z4i4ihCycmMGDr1v-b
"One of the arguments does not appear to be a valid LSDA file"
i am getting this kind of error.
It could be an error while saving the file. I have never got this soft of error before.
Thanks a lot. Very useful
you are welcome. Please like and subscribe for more videos.
Dear Ameen sir, is the yield stress of pure aluminium SIGY = 13 Mpa? so that in Gpa units it becomes 0.0133 GPa as per tutorial. Please confirm sir. Thank you.
Yes. You are correct.
Hy i am new to Ls Dyna .
i follow your above tutorial and the problem i faced is that whem I run the simulation, it terminated.
I will be thankfull.
Kind Regards
Rab Nawax
What error does it say? You can read the message file to know what is the error.
can I get a .k file for this tutorial?
Thanks
This video is 7 years old. I don't have the model anymore. Everything is explained step by step, you can create your own from scratch.
Dear Ameen, why the rupture not occurred in the center of specimen
Not very fine mesh may be the cause of this...
Hello mr Ameen, I would like to know if you can do a tutorial of importing an assembly and mesh it and simulate it, also I would like to know if it is possible to contact you personally. Thanks
Hello Hamza, check out my bird strike tutorial where I imported igs file and mesh it. Also, see my playlist: MESH IT WITH PREPOST.
@@AmeenTopa Thank you
Looking for the software everywhere. Is there any student version for free available ?
To make the input file you need LS Prepost which is free to download from LSTC website. You can run the code on other solvers for example ANSYS solver.
Thanks for your suggestion. Can I do it also with Abaqus CAE ?
Sorry, I don't have any background with Abaqus.
by the way, this handsome guy is myself. HaHa
smart is the new sexy, they said..haha
Brother after importing this cad file, iam not getting geometric parts.
(Part 1) ..
Hi there, it might be that your view setting is different, meaning the part is there but it is not visible. Also, make sure you import as igs.
@@AmeenTopa Can you please help me in solving the same issue? I'm new to LS-DYNA. Please help
However, I imported it as an IGS file
After you import, you need to mesh first then PART 1 will appear.
@@AmeenTopa Thank you very much. My bad
So why ls directly cant create stress strain curve
You need to do it manually. The software doesn't have this option. Check my tutorial on Tensile Test with solid elements. I think I did it there.
Yes i did tk u for your time .....i was also looking about scripting in cae do you thik it could be useful as a beginner
Depends on what is your goal. If you have a lot of data and cases, then scripting can save lots of your time
Well although LS Dyna is such a powerful and amazing software but still compared to the ANSYS Structural GUI, it is much more cumbersome to use, just as an example, how difficult it is to tell the software that a particular node set has to be constrained and given certain degrees of freedom and boundary conditions. ANSYS Workbench GUI is the best.
Each software has its pros and cons. Although ANSYS Workbench is very user-friendly, it cannot do the simulation of complicated problems.
Proof: just look into the numerical simulations done in scientific journals. Even though LS-DYNA is not very user-friendly, it is more commonly used compared to ANSYS Workbench.
@@AmeenTopa
Perhaps the best would be to use the combination of both i.e. ANSYS-LS Dyna, Where one can from the user friendly characteristics of ANSYS Workbench GUI as well as its Vast Material Library (which perhaps is missing in LS Dyna) and the power of LS Dyna.
Yes ANSYS has a vast library of predefined material properties, like you can just choose your part to be structural steel A36 or aluminum alloy AA6061. But LS-DYNA has more options with regards to material models: you have Elastic model, Viscoelastic, Johnson Cook, Bilinear Model, Piecewise Plasticity Model...etc.
For a more friendly-user interface, you can try Oasys Software Suite.
İf you know that Can you answer the question?
İs knowledge of varmintal webpage reliable about license right? Because I do not use information that no license right.
İ wanna ask you
Thank you. Have a good day
You can contact the owner of the website. If you are lucky, he will reply.
I don't really understand what do you mean about the license. If you mean copyright, then I think no problem to use the data in the website provided that you give proper referencing. Data is published on an open domain (public) websites are accepted in most scientific journals, but don't forget to cite.
Dear Ameen, Could you please make a tutorial to define different Boundary Condition> I'm looking everywhere for someone who could explain how to do with EM Solver, I want to put a potential difference on two ends of a copper mesh. I have a material property like Temperature dependent Conductivity and Stress strain data of Elemental Cu. it's been a week now and my stress is increasing every sleepless night. I hope you reply.
My email ID is alexy.abin.abbs@gmail.com
Dear Alexy, I am sorry that I can't help you. I have never used the EM solver.
hi it is showing termination error
If you follow the steps exactly, you won't be getting any errors. Please recheck your steps.
Thank you so much Ameen
you are most welcome bro
Thanks you very much Amen! If you know some useful website like Varmintal and GrabCAD can you share it please ^^
You are most welcome. Please do follow my channel and share my videos with your colleagues.
There are other website that I usually refer to as such: www.dynamore.de/en and www.dynaexamples.com
You can check: www.lancemore.jp/ for awesome samples of LS-DYNA simulations.
Ameen, legend ni
Thank you bro
@@AmeenTopa Bos nak tanya sikit. Saya guna model SDOF base excitation. Untuk plate bawah, saya define curve letak acceleration (experiment), tapi bila dah abes simulate tak jadi, plate bawah tak bergerak langsung padahal dah assign acceleration. Agak2 apa masalahnya. Tenkiu
@@muhammadazhar3572 rigid plate? Maybe you are fixing the rigid material.
Also, check the units of the acceleration and the units in your simulation. Make sure it is consistent. Are you using
m, s, kg or
mm, ms, kg, or
mm, s, tonne.
@@AmeenTopa yes, rigid plate. unit pakai, mm, ms, kg. unit semua dah convert guna matlab
@@muhammadazhar3572 rigid plate will not work. Put elastic material.
Thank you
You're welcome. Please share my videos so it helps more people!
@@AmeenTopa All Right
Dear Ameen, why the rupture not occurred in the center of specimen
Hi, this is due to the way the numerical calculation is done in the background.