@@AmeenTopa Sir I wanted to solve similar ALE problem on student solver, but shows error termination. Keywords are checked and corrected. So no problem in meshing and keywords.
Thank you a lot! I just wondering before whether something wrong in my modeling process or detailed paratermeters setting. Explanations in the video is specific and professional. Thanks again!
@@AmeenTopa Of course I will. By the way, Dr. Topa, I have viewed your google scholar and my main interest is about structure engineering. Would you mind having more conversation together?
@@AmeenTopa I have a question about the Johnson Cook material. Are the units SI specific for the following parameters: A,B and C. My project is U.S. customary units such as lbs, in, sec
Hii sir I am Akshay, i have seen your blast simulation video. I have also tried the same as yours, I am getting problem related to ALE multimaterial section ELform 11 is not applying over there. If another ELform kept like -2 or -1 the blast is going out of air domain. Sir I request you to please provide me the solution regarding the problem. Thankyou sir
Hi there, for the TNT and AIR, you need to use ELFORM = 11 in SECTION SOLID. If this option does not appear to you, then maybe you are using an old version of LS-PREPOST and you need to download the latest one. ELFORM = -2 and -1 are for structural parts like the concrete or steel parts.
Thanks your video. It is very useful. In CFD simulation, I can estimate the size air domain, but I do not know air domain in blast simulation follow what standard? How do you decided dimension of air domain? If it was large, the mesh would be heavy, otherwise if it was small, it was not satisfied non-reflection condition when TNT was exploded.
Hello, I have a question, how can I set tnt to be transparent and show the plastic strain of concrete at the same time, my result can only make all parts show the strain result，How can I set tnt to be transparent and display the plastic strain of concrete at the same time? My result can only allow all parts to display the cloud image, but cannot make one part display the result and the other part keep the original color
Hourglass are necessary if you are using ALE method for solid elements. Using the latest LSDYNA Solvers, it will be automatically considered if you forgot to define it.
I am a person who recently commented on "Sphere Drop on Water with ALE method". I was able to create an air area by referring to this video. I would like to use DEM and ALE together to analyze the phenomenon of objects falling freely onto sand in an air region, but is this possible? Also, when I try it myself, it says that the time required for analysis is 20,000 days. Is this possible?
i have problem say : *** Warning 40487 (SOL+487) max prin strain of element 18510 at int. point 1 NaN > failure crit 1.0000E-01 at time 2.8082E-01 solid element 18408 failed at time 2.8082E-01 solid element 18409 failed at time 2.8082E-01 solid element 18410 failed at time 2.8082E-01 solid element 18508 failed at time 2.8082E-01 node number 20512 deleted at time 2.8082E-01 solid element 18509 failed at time 2.8082E-01 node number 20513 deleted at time 2.8082E-01 solid element 18510 failed at time 2.8082E-01 do you know how to fix it sir?
That's not a problem. It is just a message telling you that some elements are being deleted as they reached the maximum principle strain defined in MAT ADD EROSION.
I have followed all the steps you had done but I face a problem the file act as there is no exploaion and the running time is very small less than 1 second . when I open the 3DPLOT I find there is no effect for the explosion and there are not any deleted nodes in the run out file.
@@AmeenTopa I will follow it again.. Thank you. But l have another question the distribution of the explosion appears By defult or l have to change the sitting to show it?? as I tried several models and I can see the effect of the explosion but I can not appear its distripution.
@@nancyyounan-or5wq You need to hide the solid mesh of air and explosive and show the fluid(ale) mesh. Check the post processing part of this video again.
@@raviprasanth3675 Sorry, your request is very specific and I do not think many will be interested. You may contact me privately if you needed private consultation.
Dear Ameen, I tried to model this exact same problem but I am not able to see the part 5 and part 6 i.e., ALE group 1 and ALE group 2. I have checked that I have assigned the ALE>multi-material group keyword, could you please help me out! Thank you.
Dear Yash, First, make sure you are using the latest LS-Prepost. Secondly, make sure that the correct ELFORM is used for the ALE parts. During the preprocessing (in the k file), you cannot view the MM_ALE groups. It is only visible in the post processing. Make sure to tick on the small box next to 'Fluid(Ale)' on the "Assembly and Select Part" window.
@@AmeenTopa Dear Ameen sir. i met some problems when performing my simulation about concrete beam under blast loadings with FSI. I found when the largrange grid is the same ,if u thinner the Euler grid , the blast wave spreads slower in air ,and the reflect of the beam is not good.can you give me some advice? Thank you very much1
@@AmeenTopa but i have tried again,when the lagrange and ale have the relative mesh size, the coupling between the ale and lagrange does not work well. i dont know what problem it is, so i wonder know if you can help me check my kword?
Dear @@mohamedhemeda2438 Mass = density x volume. Density of TNT is fixed, around 1600 kg/m3. We cannot change. So, if you want to have heavier mass of TNT, then you need to increase the size of volume of the initial charge.
Hello, Amen. Thank you for your wonderful tutorial, its very helpful for my master degree. But I have an error on LS-Run after starting solving... *** Error 11115 (KEY+1115) Part ID 2 is using stochastic material option but no *DEFINE_STOCHASTIC_VARIATION or *DEFINE_HAZ_PROPERTIES keyword is used. *** Error 10133 (KEY+133) input data failed with: 2 errors Please help me...
This example has no direct reference. I am not referring to any article for this tutorial. The point is only to know the steps on how to set up the analysis of blast with ALE method. That's why I attached a lot of research papers from which you can get the properties of TNT material.
Hello sir, thank you for this video. I had a question regarding the ALE Air domain. What is the type of boundary condition that is implicitly applied here ? If I were to simulate confined blast in a cube chamber would modeling the cube by the air domain with one of the wall being a lagrangian structure generate the same results as if I were to fully model the cube as a lagrangian structure and put it inside a bigger ALE air domain ? Thank you very much for your content and answers
If it is a confined blast, then it is more efficient to not model the Lagrange cube. Just use *BOUNDARY SPC NODE SET or *ALE ESSENTIAL BOUNDARY to fix the outer surface of the air domain.
@@AmeenTopa Hello sir, i'm sorry to bother you but you are truly of great help. I have two question for you and it would be awesome if you could answer them. 1 - How can I specify the initial internal pressure of the TNT so that the material is at atmospheric pressure at t=0 like the ALE domain ? 2 - I couldn't find in lsdyna a damage model that rely on elongation at break, are there any model like that ? Thank you very much for everything
@@theodose3 1 - I have no answer to this. You can try different values of E0 in the equation of state for the TNT. 2 - You may want to check ADD DAMAGE GISSMO.
I don't really understand your question. If you meant how to measure the pressure from the blast, then you can plot the pressure history of an element in the structure.
That value is usually taken from the literature. If you study the chemistry of explosives, then you will know more about the parameters in MAT HIGH EXPLOSIVE BURN.
Hi, thank you for the videos.they are wonderful.I have made a model similar to yours. However, the explosion does not happen. Do you have any idea what might be the reason?
Please try to follow the example again, step by step. Others have make it and didn't face the same problem as you did. They might be a problem in the material input.
@@arezo2242 No. For the concrete, you can use MAT_CSCM as I did in the tutorial: "Wrecking Ball and Reinforced Concrete" You said the explosion didn't happen, so the problem shouldn't be the EOS or MAT of the concrete.
Hello, sir. I want to ask why Vx is 40 in shape Measher at 2:30, and there is another 40 in the next input box I mean, why is the set step 40? I tried to change its value without any change.
Step 40 means if I clicked on the increment arrow it will increase by 40, so it will jump from 40 to 80, then to 120, then to 160 etc... There is no need to be concerned about this value if you are typing the element size manually.
Thanks for tutorials! I guess you heard about the CESE solver for blast and fluid-solid interaction simulations. Do you plan to prepare a tutorial about CESE solver?
@@AmeenTopa I have another question now: I want to create a perfect spherical mesh for TNT in air. For this purpose, I cannot subtract TNT from elements of air. I mean, TNT is also penetrating with the air, similar to composite beam in this video. In this case, I could not achieve any moving ALE fluid mesh. What should I do to solve an intertwining TNT & air elements? Thanks in advance.
How do we adjust mass of explosive? Or do we have to adjust volume (size) of TNT elements multiplied by its density to cater for the exact amount of TNT used?
Hello, Ameen! How can I plot different characteristics at some point( for example I wanna plot pressure curve in point x= 1, y=1 ,z=1,but it's not a node) ? thanks
In contact automatic surface to surface, shouldn't the concrete be the master and I-beam the slave but you have done it the other way around. Is there any reason for it?
It doesn't matter because we are using AUTOMATIC surface to surface. If you are using Surface_to_Surface which is not Automatic, then slave should be the concrete and I-beam is the master. The slave is the parts that is moving. Master is the part that is stationary. Note that this is only for SURFACE TO SURFACE contact. If it is NODES TO SURFACE then the nodes should be the slave always.
For easier control of the mass, you can just use LOAD BLAST ENHANCED. Check out my tutorial on Blast Simulation here th-cam.com/video/B1vGRU2a5f0/w-d-xo.html
Hı Ameen Topa. i have a question. İn this tutorial, you didn't write any value about quantity of explosive. How much does explosive detonate in this tutorial and how calculated it. Thank you for everything.
@@AmeenTopa do I understand your telling ? after we give material and section properties, ls dyna calculate material mass how multiply density with volume.
@@zafertoral5840 In the material model, we define the density. From when we create the mesh, we give the dimensions. From volume and density, the mass is calculated.
@@AmeenTopa Indeed. I will share and recommend my colleagues to keep in touch with this channel. Ammen Topa, If you could please shoot one more new LS-DYNA and/or LS-PrePost tutorial video on "Steel concrete composite beam under blast load", where the SCC beam is planned to be made using advantage of symmetry from a reinforced concrete slab with "I" or "H" section structural steel beam which then finally reduced to quarter (1/4) of the FEA model (i.e. SCC beam with RC slab with "C" or Channel section). Thanks in advance.
Dear Ameen Sir, At 9:50 I saw the Simulation and experimental results of the unconfined compression test result. waiting for the next tutorial about the compression test of concrete.
You can check this tutorial for the compression test: th-cam.com/video/jIUcQx6XZ2E/w-d-xo.html The only difference thing is the material model. You can just put the concrete.
So helpful; thanks I have a problem with control of TNT after detonation. I use a rigid cylinder to control direction of TNT after detonation; but TNT path through the rigid after detonation, how can I control that?
First, does it pass through as if the cylinder doesn't exist or there is leakage in the cylinder? Secondly, the cylinder is shell or solid? If it is shell, check the normal of the shell. See my tutorial on sloshing. I have explained about this there.
@@AmeenTopa I have a cylinder closed on one side; 1 kilogram of TNT is placed inside it. I want the wave to come out of the open side after the explosion.
@@abolfazlkhalilijam8096 okay. Try reducing the timestep scaling factor. If still didn't work. Apply boundary conditions on the TNT nodes instead of using a solid containers.
Ameen Topa sir, I increased the termination time to a 100ms so that there are a 1000 timesteps. But in the animation, the concrete elements kept on getting deleted right till the end and there was also no clearance of the blast wave. How to resolve that?
Also it took 4 hours for the analysis despite putting the memory of 1000m and 4 cpu. Can you please tell me ways to speed up the analysis on smp solver.
That's normal. You need go have a very fine mesh. However, not all concrete will erode. Especially the concrete on the lower side below the I beam. If all concrete are deleted in your simulation, then it means there is something wrong with the material properties. You are using 4 cpu, so that's amount of time is standard. You need more processors to make it faster or you can reduce the number of the elements in the model.
@@AmeenTopa Isn't SPC a fixed boundary condition? I do not understand why fixed constraints are symmetrical, don't understand well, can you explain it in more detail?
@@해석학교 Let's say we want to do symmetry around the XY plane. The nodes which exist on the XY plane, cannot move in the Z direction. But it can move in the X or Y direction. And how to model this constraints? Using SPC boundary condition.
@@AmeenTopa Could you tell me your email? Can you give me an example of how to give the symmetry condition of the model I'm doing after looking at the picture?
Dear Ameen Sir, This method is great. Currently, I am finding out " Coupling LBE-ALE method". If you have any materials about this method, Could you send me to refer?. Thank you so much.
Check the following references: www.dynamore.it/de/download/papers/forum10/papers/J-I-01.pdf www.dynalook.com/conferences/12th-international-ls-dyna-conference/blast-impact20-d.pdf link.springer.com/article/10.1186/s40712-020-0116-3 www.researchgate.net/publication/230968679_A_coupling_of_empirical_explosive_blast_loads_to_ALE_air_domains_in_LS-DYNAR ascelibrary.org/doi/10.1061/%28ASCE%29ST.1943-541X.0002782
Negative volume can be due to many reasons. If you are using Solid Lagrange elements, you can check out this link: www.dynasupport.com/howtos/material/negative-volume-in-soft-materials
Thanks for passing by. Please subscribe to support my channel. I only covered 1% of what this software can do. I need 10 lifetimes in order to learn all its capabilities!
@@AmeenTopa Definitely subbed. Your tutorials are a blessing. My life has been nothing but this software past few days. I'm doing my FYP on combined blast-impact load on RC beam using LS-Dyna but my lecturer is not familiar with it. Now just trying to figure out how to model reinforcement in concrete.
@@Randomkloud lol, if your supervisor is not familiar with the software, then he should give you a different topic that uses a different software. Let me guess, from a Malaysian university, right? 😌🙃🙃
@@AmeenTopa haha, you guessed it right brother, I'm Malaysian studying in local uni. My lecturer knows etabs but most of the recent literature on my topic is using ls dyna. Understandably the papers don't go into full detail of how they set up the software. My priority now is just to verify a model with a paper's experimental result so I know I'm not just putting garbage in ls dyna 🤣
@@Randomkloud you are not alone, many students come to me with the same problem, that is, their supervisors cannot help them. Going back to your question, check out my Tutorial Reinforced Concrete Slab and Wrecking Ball.
@@AmeenTopa Of course, I have already recommended this video to my colleagues. BTW, are you familiar with stress initialization? I met some headache problems in dynamic relaxation, can you leave your email for a further discussion? Thank you so much!
Thank you. For dynamic relaxation, I don't have a tutorial but you can check this video here: th-cam.com/video/ATMq_fi35Uk/w-d-xo.html If you still got doubts, leave your email here and I will follow up in my free time.
Salam alykoum ameen, i really like your work masha'allah but if i can ask you something. ireally need your help since im doing my internship about explosions and i'll be gratefull if you can send me the K.File of the simulation with greater Air domain, thank you very much !
WaAlaikumussalam. I am glad you found my work useful. Unfortunately, I don't have the k file anymore. All the steps are clearly explained in this video. So you can try and do it yourself.
thank you for the answer, but i was reffering to the k file of the last simulation you did (with the finer mesh and bigger air domain) i could do the simulation you showed and i followed all the steps but i just wanted to see the k.file where you used a finer mesh and a bigger air domain. i added you on Linkdin if it doesnt bother you to tell you about the subject of the internship.
A talented guy making things easy. Thank you Sir.
You are welcome, please share my video so more people can learn. Thanks.
@@AmeenTopa Sir I wanted to solve similar ALE problem on student solver, but shows error termination. Keywords are checked and corrected. So no problem in meshing and keywords.
What's the error? If it is a solver problem, the error message will say that.
Please take note that the student version has a limit to file size.
Thank you a lot! I just wondering before whether something wrong in my modeling process or detailed paratermeters setting. Explanations in the video is specific and professional. Thanks again!
You are welcome! Please share my videos so more people can learn!
@@AmeenTopa Of course I will. By the way, Dr. Topa, I have viewed your google scholar and my main interest is about structure engineering. Would you mind having more conversation together?
Yeah sure, you can find me on social media: Facebook, or LinkedIn.
Thank you much! This helps out significantly with the last part of my project!
I am glad it help out. Please share my videos so your friends and juniors can benefit too 😁
@@AmeenTopa I have a question about the Johnson Cook material. Are the units SI specific for the following parameters: A,B and C. My project is U.S. customary units such as lbs, in, sec
@@condeo92 A and B has the units of stress and C is dimensionless.
Hii sir I am Akshay, i have seen your blast simulation video.
I have also tried the same as yours, I am getting problem related to ALE multimaterial section ELform 11 is not applying over there.
If another ELform kept like -2 or -1 the blast is going out of air domain.
Sir I request you to please provide me the solution regarding the problem.
Thankyou sir
Hi there, for the TNT and AIR, you need to use ELFORM = 11 in SECTION SOLID. If this option does not appear to you, then maybe you are using an old version of LS-PREPOST and you need to download the latest one.
ELFORM = -2 and -1 are for structural parts like the concrete or steel parts.
@@AmeenTopa thankyou sir
Thanks your video. It is very useful. In CFD simulation, I can estimate the size air domain, but I do not know air domain in blast simulation follow what standard? How do you decided dimension of air domain? If it was large, the mesh would be heavy, otherwise if it was small, it was not satisfied non-reflection condition when TNT was exploded.
Unfortunately, there is no one rule that fits all cases.
I have done the same, but I'm not getting the detonation of the TNT. Can you please share your .k file?
Sorry, I don't have the file anymore.
This tutorial is more than one year old and everyone else managed to do it. Please check your steps again.
Hello, I have a question, how can I set tnt to be transparent and show the plastic strain of concrete at the same time, my result can only make all parts show the strain result，How can I set tnt to be transparent and display the plastic strain of concrete at the same time? My result can only allow all parts to display the cloud image, but cannot make one part display the result and the other part keep the original color
thank you,sir. I tried to change the color of a part one by one, and finally showed it together. Its succeeded.
Which processor you have..in which analysis part was done in only 10 mintues??
Usually I cut or fast-forward the part where I run the models.
Excuse me sir, I wanna know whether the HOURGLASS cards for ALE parts are necessary in free air explosion simulation by LS-DYNA？
Hourglass are necessary if you are using ALE method for solid elements. Using the latest LSDYNA Solvers, it will be automatically considered if you forgot to define it.
I am a person who recently commented on "Sphere Drop on Water with ALE method".
I was able to create an air area by referring to this video.
I would like to use DEM and ALE together to analyze the phenomenon of objects falling freely onto sand in an air region, but is this possible?
Also, when I try it myself, it says that the time required for analysis is 20,000 days. Is this possible?
There might be something wrong in the material model. Also, I am not sure if DEM and ALE can be coupled. I haven't seen it done before.
i have problem say :
*** Warning 40487 (SOL+487)
max prin strain of element 18510 at int. point 1
NaN > failure crit 1.0000E-01 at time 2.8082E-01
solid element 18408 failed at time 2.8082E-01
solid element 18409 failed at time 2.8082E-01
solid element 18410 failed at time 2.8082E-01
solid element 18508 failed at time 2.8082E-01
node number 20512 deleted at time 2.8082E-01
solid element 18509 failed at time 2.8082E-01
node number 20513 deleted at time 2.8082E-01
solid element 18510 failed at time 2.8082E-01
do you know how to fix it sir?
That's not a problem. It is just a message telling you that some elements are being deleted as they reached the maximum principle strain defined in MAT ADD EROSION.
@@AmeenTopa how do you find the EOS for aluminium or other material sir?
@@abdullahfaqih9745 you can search in the literature. Go to google scholar or research gate.
Looks very nice, thank you indeed for sharing
Thanks. Please share this video if you find it useful.
I have followed all the steps you had done but I face a problem the file act as there is no exploaion and the running time is very small less than 1 second . when I open the 3DPLOT I find there is no effect for the explosion and there are not any deleted nodes in the run out file.
Please follow the steps again carefully. This video is uploaded since two years ago and no one else has encountered similar problem.
@@AmeenTopa I will follow it again.. Thank you. But l have another question the distribution of the explosion appears By defult or l have to change the sitting to show it?? as I tried several models and I can see the effect of the explosion but I can not appear its distripution.
@@nancyyounan-or5wq You need to hide the solid mesh of air and explosive and show the fluid(ale) mesh. Check the post processing part of this video again.
@@AmeenTopa ok. Thank you 🙂
Can u help me how to use volume fraction geometry, I need to simulate a composite plate sandwiched with a shear thickening fluid.
And if u suggest how to incorporate and procedural steps for the above problem
@@raviprasanth3675 Sorry, your request is very specific and I do not think many will be interested. You may contact me privately if you needed private consultation.
great job my friend！I wonder how the result would have been different if I had not separated the i-beams from the concrete beams.
You can give it a try and see! I assume more of the concrete element will be deleted!
Dear Ameen,
I tried to model this exact same problem but I am not able to see the part 5 and part 6 i.e., ALE group 1 and ALE group 2. I have checked that I have assigned the ALE>multi-material group keyword, could you please help me out!
Thank you.
Dear Yash,
First, make sure you are using the latest LS-Prepost.
Secondly, make sure that the correct ELFORM is used for the ALE parts.
During the preprocessing (in the k file), you cannot view the MM_ALE groups. It is only visible in the post processing.
Make sure to tick on the small box next to 'Fluid(Ale)' on the "Assembly and Select Part" window.
@@AmeenTopa Got it. Thank you.
Sir, is the explosive volume defined in the VO (Initial Real Volume) in the JWL equation or by the volume of the TNT part?
Nope. The explosive volume is defined by the dimensions of the part that represent the TNT.
@@AmeenTopa yes,i think so!
thank you very much for your work! it is very helpful for me. And i am waiting for ur tutorial with S-ALE method about the concrete under blast.
Check out the following document:
ftp.lstc.com/anonymous/outgoing/hao/sale/tutorials/S-ALE_Solver_1.pdf
@@AmeenTopa thank you very much!
@@AmeenTopa Dear Ameen sir. i met some problems when performing my simulation about concrete beam under blast loadings with FSI. I found when the largrange grid is the same ,if u thinner the Euler grid , the blast wave spreads slower in air ,and the reflect of the beam is not good.can you give me some advice? Thank you very much1
As a general rule, the mesh or grid for both Lagrange and ALE should be relatively the same size
@@AmeenTopa but i have tried again,when the lagrange and ale have the relative mesh size, the coupling between the ale and lagrange does not work well. i dont know what problem it is, so i wonder know if you can help me check my kword?
Sir iam getting the error of ALE part is beyond initial void what could be the reason.
Thankyou
Are you using INITIAL VOLUME FRACTION or INITIAL VOID?
Initial void
@@akshayraj2426 the part used in this keyword should have ELFORM = 12.
Sir at the end of lsdyna manager it is showing like forttl severe program exeption acess violation
This sort of error is due to the solver, as discussed recently in the LSDYNA Gmail group. Check that one for more details..
The I BEAM doesn't have any erosion??
Yes, the TNT mass is small anyway..
@@AmeenTopa how to control the charge weight herein
i mean to define the charge weight
Dear @@mohamedhemeda2438
Mass = density x volume.
Density of TNT is fixed, around 1600 kg/m3. We cannot change.
So, if you want to have heavier mass of TNT, then you need to increase the size of volume of the initial charge.
Hello, Amen. Thank you for your wonderful tutorial, its very helpful for my master degree. But I have an error on LS-Run after starting solving...
*** Error 11115 (KEY+1115)
Part ID 2 is using stochastic material option but no
*DEFINE_STOCHASTIC_VARIATION or *DEFINE_HAZ_PROPERTIES keyword is used.
*** Error 10133 (KEY+133)
input data failed with: 2 errors
Please help me...
Did you have this error when you tried to do the model in this video?
@@AmeenTopa Yes, I tried to recreate your model
@@Ya-Salo Make sure that you are using exactly the same material model that I used in the model.
I think you are using MAT JOHNSON COOK STOCHASTIC. This is not the model that I used.
How do I delete a unit that has completely failed
Use MAT ADD EROSION..
Thank you so much sir but Sir may I know which research paper it is can you put the link please?
May I know which paper you are referring to exactly? I have put some related references in the video description.
@@AmeenTopa I'm Referring rc beam under blast loading sir
This example has no direct reference. I am not referring to any article for this tutorial. The point is only to know the steps on how to set up the analysis of blast with ALE method.
That's why I attached a lot of research papers from which you can get the properties of TNT material.
Hello sir, thank you for this video. I had a question regarding the ALE Air domain. What is the type of boundary condition that is implicitly applied here ?
If I were to simulate confined blast in a cube chamber would modeling the cube by the air domain with one of the wall being a lagrangian structure generate the same results as if I were to fully model the cube as a lagrangian structure and put it inside a bigger ALE air domain ? Thank you very much for your content and answers
If it is a confined blast, then it is more efficient to not model the Lagrange cube. Just use *BOUNDARY SPC NODE SET or *ALE ESSENTIAL BOUNDARY to fix the outer surface of the air domain.
@@AmeenTopa Thank you very much for the advice !
@@AmeenTopa Hello sir, i'm sorry to bother you but you are truly of great help. I have two question for you and it would be awesome if you could answer them.
1 - How can I specify the initial internal pressure of the TNT so that the material is at atmospheric pressure at t=0 like the ALE domain ?
2 - I couldn't find in lsdyna a damage model that rely on elongation at break, are there any model like that ?
Thank you very much for everything
@@theodose3 1 - I have no answer to this. You can try different values of E0 in the equation of state for the TNT.
2 - You may want to check ADD DAMAGE GISSMO.
@@AmeenTopa Once again thank you sir
Hi, Thank you for the videos, I am creating a model similar to yours, Can you please explain how did you come up with the pressure of TNT?
I don't really understand your question. If you meant how to measure the pressure from the blast, then you can plot the pressure history of an element in the structure.
@@AmeenTopa Thank you for you reply, I am talking about the PCJ value (26 GPA) in the material definition (Mat_High_ explosive_ burn)?
That value is usually taken from the literature. If you study the chemistry of explosives, then you will know more about the parameters in MAT HIGH EXPLOSIVE BURN.
Hi, thank you for the videos.they are wonderful.I have made a model similar to yours.
However, the explosion does not happen. Do you have any idea what might be the reason?
Please try to follow the example again, step by step. Others have make it and didn't face the same problem as you did. They might be a problem in the material input.
@@AmeenTopa I wanted to model the reinforced beam.I used some part of your model.should I have an equation of state for concrete.
Thank you.
@@arezo2242 No. For the concrete, you can use MAT_CSCM as I did in the tutorial: "Wrecking Ball and Reinforced Concrete"
You said the explosion didn't happen, so the problem shouldn't be the EOS or MAT of the concrete.
Hello, sir. I want to ask why Vx is 40 in shape Measher at 2:30, and there is another 40 in the next input box
I mean, why is the set step 40? I tried to change its value without any change.
Step 40 means if I clicked on the increment arrow it will increase by 40, so it will jump from 40 to 80, then to 120, then to 160 etc...
There is no need to be concerned about this value if you are typing the element size manually.
@@AmeenTopa Thank you, sir. This is really a stupid question. Thank you for your patience. You are a good teacher
@@shiqizhang3532 You are welcome. There is no stupid questions.
Please share my video if you find them useful! :D
@@AmeenTopa I will. I was introduced by someone else.
You are a very famous person
@@shiqizhang3532 Thank you and feel free to drop a comment on any of my videos if you have a question.
Thanks for tutorials! I guess you heard about the CESE solver for blast and fluid-solid interaction simulations. Do you plan to prepare a tutorial about CESE solver?
Yes, I know about this solver and used it before. However, I have no plans for any tutorial for it soon due to my time constraints, unfortunately.
@@AmeenTopa O.K. then. My other question is; which keyword or parameter should be changed depending on the mass of TNT?
@@eminakc Using ALE method, you create a mesh for the initial shape of the TNT. So, by controlling the shape (size) of the TNT, you control the mass.
@@AmeenTopa Thank you!
@@AmeenTopa I have another question now: I want to create a perfect spherical mesh for TNT in air. For this purpose, I cannot subtract TNT from elements of air. I mean, TNT is also penetrating with the air, similar to composite beam in this video. In this case, I could not achieve any moving ALE fluid mesh. What should I do to solve an intertwining TNT & air elements? Thanks in advance.
How do we adjust mass of explosive?
Or do we have to adjust volume (size) of TNT elements multiplied by its density to cater for the exact amount of TNT used?
Yes. You need to change the volume of the TNT. So the mesh must be adjusted.
@@AmeenTopa okay 👍🏻
Hello, Ameen! How can I plot different characteristics at some point( for example I wanna plot pressure curve in point x= 1, y=1 ,z=1,but it's not a node) ? thanks
Dear Слава,
Do you mean the blast pressure at point (1,1,1)? You can try to read about *DATABASE_TRACER in the theory manual.
@@AmeenTopa Thank you, Ameen! I solve my problem.Thanks to you!
what is element violates heuristic shape criterion error warning sir?? how to overcome this!?
This is due to poorly meshed elements. You need to remesh the parts and generate elements with better aspect ratios.
In contact automatic surface to surface, shouldn't the concrete be the master and I-beam the slave but you have done it the other way around. Is there any reason for it?
It doesn't matter because we are using AUTOMATIC surface to surface. If you are using Surface_to_Surface which is not Automatic, then slave should be the concrete and I-beam is the master. The slave is the parts that is moving. Master is the part that is stationary.
Note that this is only for SURFACE TO SURFACE contact. If it is NODES TO SURFACE then the nodes should be the slave always.
@@AmeenTopa Thank you sir for the explanation.
how can i define the weight of explosive in this modeling
if the explosive charge is 25kg or is 1000kg , in which step can i define this
Dear Hemeda, you need to increase the volume of the TNT initial volume
For easier control of the mass, you can just use LOAD BLAST ENHANCED. Check out my tutorial on Blast Simulation here
th-cam.com/video/B1vGRU2a5f0/w-d-xo.html
Hı Ameen Topa. i have a question. İn this tutorial, you didn't write any value about quantity of explosive. How much does explosive detonate in this tutorial and how calculated it. Thank you for everything.
You can measure the mass and dimensions from the 'measure' tool. Shortcut to this tool: Press F4 key.
@@AmeenTopa do I understand your telling ? after we give material and section properties, ls dyna calculate material mass how multiply density with volume.
@@zafertoral5840 In the material model, we define the density. From when we create the mesh, we give the dimensions. From volume and density, the mass is calculated.
@@AmeenTopa thank you for everything
you are welcome and all the best@@zafertoral5840
Thank you so much. That's a kind of you. Keep it up.
Glad it helped. Please share my videos so they can reach and benefit more people!
@@AmeenTopa Indeed. I will share and recommend my colleagues to keep in touch with this channel. Ammen Topa, If you could please shoot one more new LS-DYNA and/or LS-PrePost tutorial video on "Steel concrete composite beam under blast load", where the SCC beam is planned to be made using advantage of symmetry from a reinforced concrete slab with "I" or "H" section structural steel beam which then finally reduced to quarter (1/4) of the FEA model (i.e. SCC beam with RC slab with "C" or Channel section). Thanks in advance.
Dear Ameen Sir,
At 9:50 I saw the Simulation and experimental results of the unconfined compression test result.
waiting for the next tutorial about the compression test of concrete.
You can check this tutorial for the compression test:
th-cam.com/video/jIUcQx6XZ2E/w-d-xo.html
The only difference thing is the material model. You can just put the concrete.
thank you sir
Thank you so much sir! it's so helpful
Most welcome! Please share my videos so it can help more people! :)
hello professor inotice you didn't set non-reflective condition,why please answer me in your free time thank you!
Non-reflective boundary (*BOUNDARY NON-REFLECTIVE) works only for elastic waves, and therefore is not appropriate for air blast.
To eliminate air blast boundary reflections, increase the distance from the boundary to the region of interest.
So helpful; thanks
I have a problem with control of TNT after detonation. I use a rigid cylinder to control direction of TNT after detonation; but TNT path through the rigid after detonation, how can I control that?
First, does it pass through as if the cylinder doesn't exist or there is leakage in the cylinder?
Secondly, the cylinder is shell or solid? If it is shell, check the normal of the shell. See my tutorial on sloshing. I have explained about this there.
@@AmeenTopa I have a cylinder closed on one side; 1 kilogram of TNT is placed inside it. I want the wave to come out of the open side after the explosion.
Are you doing something like explosively formed projectile?
@@AmeenTopa I am investigating the effect of the TNT explosion on the steel plate, but the TNT comes out of a chamber in the form of a cylinder.
@@abolfazlkhalilijam8096 okay.
Try reducing the timestep scaling factor.
If still didn't work. Apply boundary conditions on the TNT nodes instead of using a solid containers.
Ameen Topa sir, I increased the termination time to a 100ms so that there are a 1000 timesteps. But in the animation, the concrete elements kept on getting deleted right till the end and there was also no clearance of the blast wave. How to resolve that?
Also it took 4 hours for the analysis despite putting the memory of 1000m and 4 cpu. Can you please tell me ways to speed up the analysis on smp solver.
That's normal. You need go have a very fine mesh.
However, not all concrete will erode. Especially the concrete on the lower side below the I beam. If all concrete are deleted in your simulation, then it means there is something wrong with the material properties.
You are using 4 cpu, so that's amount of time is standard. You need more processors to make it faster or you can reduce the number of the elements in the model.
@@AmeenTopa ok sir, and also if I increase the memory to lets say 5000m then would it decrease the computational time?
No. I said you need more processors, not RAM.
Great job man. thanks
Thanks! Please share my videos so it reached more people!
How do you give symmetry conditions? Do you use reflective conditions?
Just used BOUNDARY SPC SET. I explained it in this video already.
@@AmeenTopa Isn't SPC a fixed boundary condition? I do not understand why fixed constraints are symmetrical, don't understand well, can you explain it in more detail?
@@해석학교 Let's say we want to do symmetry around the XY plane.
The nodes which exist on the XY plane, cannot move in the Z direction. But it can move in the X or Y direction.
And how to model this constraints? Using SPC boundary condition.
@@AmeenTopa Could you tell me your email? Can you give me an example of how to give the symmetry condition of the model I'm doing after looking at the picture?
@@해석학교 Put your email here and I will contact you in my free time.
So helpful! Thanks!!
Glad it was helpful! Feel free to share my videos so everyone else can learn too ;)
Dear Ameen Sir,
This method is great. Currently, I am finding out " Coupling LBE-ALE method". If you have any materials about this method, Could you send me to refer?. Thank you so much.
Check the following references:
www.dynamore.it/de/download/papers/forum10/papers/J-I-01.pdf
www.dynalook.com/conferences/12th-international-ls-dyna-conference/blast-impact20-d.pdf
link.springer.com/article/10.1186/s40712-020-0116-3
www.researchgate.net/publication/230968679_A_coupling_of_empirical_explosive_blast_loads_to_ALE_air_domains_in_LS-DYNAR
ascelibrary.org/doi/10.1061/%28ASCE%29ST.1943-541X.0002782
@@AmeenTopa Thank you so much.
Dear ameen sir,
Please help me to solve the negative volume during impact test of particle to substrate (i.e cold gas spray process)
Negative volume can be due to many reasons. If you are using Solid Lagrange elements, you can check out this link:
www.dynasupport.com/howtos/material/negative-volume-in-soft-materials
Nice video sir, how can I get the software for Ls-Dyna, Please help me.
www.getintopcfree.com/simulators/ls-dyna-free-download/
hello sir it is also free on its official website
You need to purchase the license for LS-DYNA. But LS-Prepost is free.
@@AmeenTopa sir can i get your mail id
Sorry I can't give my email address in public. May I know why you need to contact me personally? 😬
this was a nice birthday present lol
Happy birthday to you then! hahaha
You are wonderful
Thank you for your kind words. Please share this tutorial so more can learn!!
how on earth did u learn all this?!
Thanks for passing by. Please subscribe to support my channel.
I only covered 1% of what this software can do. I need 10 lifetimes in order to learn all its capabilities!
@@AmeenTopa Definitely subbed. Your tutorials are a blessing. My life has been nothing but this software past few days.
I'm doing my FYP on combined blast-impact load on RC beam using LS-Dyna but my lecturer is not familiar with it. Now just trying to figure out how to model reinforcement in concrete.
@@Randomkloud lol, if your supervisor is not familiar with the software, then he should give you a different topic that uses a different software.
Let me guess, from a Malaysian university, right? 😌🙃🙃
@@AmeenTopa haha, you guessed it right brother, I'm Malaysian studying in local uni. My lecturer knows etabs but most of the recent literature on my topic is using ls dyna. Understandably the papers don't go into full detail of how they set up the software. My priority now is just to verify a model with a paper's experimental result so I know I'm not just putting garbage in ls dyna 🤣
@@Randomkloud you are not alone, many students come to me with the same problem, that is, their supervisors cannot help them.
Going back to your question, check out my Tutorial Reinforced Concrete Slab and Wrecking Ball.
Excellent! THX!
You're welcome! Please share my videos so it can benefit more people! :)
@@AmeenTopa Of course, I have already recommended this video to my colleagues. BTW, are you familiar with stress initialization? I met some headache problems in dynamic relaxation, can you leave your email for a further discussion? Thank you so much!
Thank you. For dynamic relaxation, I don't have a tutorial but you can check this video here:
th-cam.com/video/ATMq_fi35Uk/w-d-xo.html
If you still got doubts, leave your email here and I will follow up in my free time.
@@AmeenTopa Thanks for sharing the video, but it can't solve my problem, my email is houge0087@gmail.com, thanks in advance!
please send me the download link of ls-dyna, thanks
www.lstc.com/download/ls-dyna
Link to download LS-DYNA:
getintopc.com/softwares/simulators/ls-dyna-free-download/
Salam alykoum ameen, i really like your work masha'allah but if i can ask you something. ireally need your help since im doing my internship about explosions and i'll be gratefull if you can send me the K.File of the simulation with greater Air domain, thank you very much !
WaAlaikumussalam. I am glad you found my work useful. Unfortunately, I don't have the k file anymore.
All the steps are clearly explained in this video. So you can try and do it yourself.
thank you for the answer, but i was reffering to the k file of the last simulation you did (with the finer mesh and bigger air domain) i could do the simulation you showed and i followed all the steps but i just wanted to see the k.file where you used a finer mesh and a bigger air domain.
i added you on Linkdin if it doesnt bother you to tell you about the subject of the internship.
@@Lotfiaeb Noted and thanks for the clarification. But I do not have that model either.