Failure strain was not defined and thus fragmentation was not considered in this model. This is because the damage was not that severe according to the experimental reference.
Thank you very much for excellent tutorial to understand the usage of curve and table keyword as well as blast load. if you provide a tutorial for Johnson cook material model with the above strain rate effect. it will be very useful to the lsdyna beginners like me....
I consider Johnson cook a bit advanced and I would like to keep my tutorials very simple. But, I will keep you comment in mind and maybe in following tutorials will be included.
Hello Sir! Your videos are extremely informative and simple to understand. Thank you so much as always! Could you please make a video on simulating rock blasting using LS Dyna and also measurement of ground vibrations generated as the result of the blasting performed.
Super useful video Ameen. Thank you so much. However, as you spent quite some time defining the strain rate of the material at the beginning of the video, you did not clarify the effects of the strain rate on the results. Thanks again for your useful videos.
Completely agree @@AmeenTopa, but I have one question regarding the strain rate effect, did you use the full stress-strain curve from the beginning of the test or did you choose the data beyond the yield stress?
@@haidermraih2559 for MAT024, we only use the stress data after the yield point. Check this video for a comprehensive explanation about this model: ruclips.net/video/J5Qjj_9Sot0/видео.htmlsi=ovFSlVW0ZyWy1zYG
Like! I did not catch, does this method simulate the action of explosion products? If the charge is located close, then the products of the explosion have a significant effect along with the shock wave.
It depends on the scaled distance. Load blast enhanced is derived from empirical data and it is not suitable for very small values of scaled distance. For close distance detonations, you need to model the explosive explicitly. Check out my tutorial on TNT Blast on Composite Beam.
It depends on the application and situation. There is no method that is 'best' for everything. If you are interested in blast with SPH, check out this video here (don't forget to read the video description) ruclips.net/video/Xidr0p6EplQ/видео.html
Hi Ameen, Thanks for your sharing. Anyways, I have some questions related to this: 1. if the top plate and the core is connected by welding, is it enough by using the same nodes for the connected surface of elements or do we need to define contact surface? 2. if the load is a pressure-time history on the top plate, is it correct if I define segment set (SSID)of the top plate and curve of pressure-time (LCID) and then used it in *LOAD_SEGMENT_SET. I am new to LS-Prepost, hope you don't mind if my questions don't make any senses. Thank again for your sharing and looking forward for your help.
Dear Lam, 1 - For connection, you can merge the duplicate the nodes which is the easier option. For more advanced modelling, you can use Contacts Tiebreak. 2 - Yes, you can use that approach too. But using Load Blast Enhanced is more accurate because the load varies depends on the incident angle, and this is not possible with Load Segment Set. Sincerely,
Ameen Topa thanks for your response. I have one more question related to my question 2. We use *LOAD_SEGMENT_SET when the load is a pressure-time curve and *LOAD_NODE_SET when the load is a force-time curve, am I right? And for DEFINE_CURVE, we can use for both pressure or force-time history right? Or are there any other ways? Thanks.
Its great tutorial sir, i wonder to know how to simulate the slope stability (geotechnical for soil and rock mechanics) under blast load (stability of slope affectef by mining blasting activity)? Realy apreciate your help sir..
Dear Mr. Topa, thank you for your excellent tutorials for LS DYNA. This one is very useful for me, but I have a question related to the shape of the charge. In your video, you only define the distance of the center of the charge, assuming it was cylindrical. Is there a way to model the shape of the charge since the pressures and impulses around the charge strongly depend on the shape?
Hi Ameen, may I ask what is your software and hardware configuration that you use for making your videos? For example, which software do you use to record your videos?
Dear Ameen, I also ran the same case, acceleration is very high (unexpected), kindly check your resultant or z acceleration for this simulation. Apart from this, I have tried sandwich foam panel using "crushable foam" as a core and "Steel plate" as a face sheets, the resultant acceleration is upto 10^6-10^5 m/s^2 which is unexpected while displacement is showing satisfactory results. Can you explain this error.
Dear Patil, what do you mean by very high acceleration? This is blast simulation and acceleration is expected to be high. Good agreement is found when comparing the displacement with test data. Thus it is validated. It is very impractical to measure acceleration in experiment. May I know on what basis you say the acceleration is very high?
@@AmeenTopa Ya agree, you are correct with the test result. But measured acceleration is very high, have you seen acceleration in powers like 3.06 x 10^6 m/s^2 ??? My purpose is to measure resultant acceleration on the panel.
Dear Patil, we are talking about explosives here, right? I don't think it is fair to compare this case of high intensity load (which can deflect a 12 mm thick steel plate) to the case when the target is human body. 1 kg of TNT blasted from a distance of 10 cm, that's crazy amount of force which will shatter human flash into pieces.
Sorry, I don't have the time to make any video requests. You can learn how to create blast load from this video. Search on my channel and you will see videos on how to model concrete slab. Combine the steps from both videos and you will get what you want. With that being said, if you are interested in private consultation session, you can contact my team.
You mean cylindrical charge, not change, right? If you want to simulate the shape of the TNT, you must use another method such as ALE or SPH. Check my tutorial TNT Blast on Composite Beam
Hi sir, While giving the termination time you have to give in seconds right because in blast enhanced card the units are in kg,m, sec, newton. Please clarify ??
Dear Sir, thank you for the tutorial. I am trying to simulate a storage tank with 100m diameter and 22.5m height under 1500kg TNT blast load based on a paper, so I followed the steps in this video and replaced the plate with a cylinder shell. However, during the solving process, warning messages of "number of blast segment normals pointing away from blast origin = 2570" showed up, and my initial kinetic energy is zero. Can you kindly guide me on this issue? Thank you very much.
Dear Mr. Topa, I followed your steps on this video precisely only changing the TNT mass to 5kg, it runs smoothly however when I try to plot the Z-displacement graph it showed me just the graph but not any numbers. Can you tell me what's wrong? Thank you
This is just a visualization matter. You need to change the colour of the font or colour or background. You can do it from the setting tabs on the top left of the Prepost window.
You are welcome. If you are doing research and benefited from this tutorial, please consider citing my article which is given in the video description.
In Blast loading validation of RCC slab, I am defining everything, the unit is in g, mm, ms and MPa in blast load and In MAT I am not defining the unit but all input in LS PRE POST IS according to blast loading unit also the software gives result but the deflection result very small compared to the experiment can you help me? in which definition I missing?
How much small is it? You can try blast on steel plate or plain concrete slab to check if your units are correct. If this give good results, then it means the problem with how you model the RCC slab.
@@AmeenTopa I mean I have to make a structure of 3 materials in proportion of 40,30 and 30 is it possible to do that? Polypropylene,mica and rubber in diff proportions in 1 structure
Yes. It is all about the material properties. You need use simple shell or solid elements but you need advanced material model to allow for the anisotropic behavior of the material.
There are errors showing in the file after rechecking the model, they are regarding "load curves are not monotonically increasing, curve 5 is not reaching the same strain value as compared to others", etc. Which result in error termination instead of normal termination. Sir, could you suggest me how to overcome this?
It might be an mistake in defining the curve or in the solver (your software is very old version) To be honest, I have never faced the error you've mentioned above.
@@AmeenTopa Sir, While rechecking my keywords, this message pops up and I have chosen solid brick elements instead of shell. I recommend, please check your model, too.
@@Nick-gj9my Please check the following paper: www.dynamore.de/de/download/papers/2012-internationale-ls-dyna-users-conference/documents/blast-impact06-a.pdf
Yo tough guy, I fixed the link. Here you go, please don't beat me up 😝😝 drive.google.com/drive/mobile/folders/1i8Upn-Sa4K0I9Zjq-qEClwHahP-dFrbl?usp=drive_open
Thank you so much! Using your method I made the research of blast impacting bollards and building facades. Great work. I really appreciate it!
You are most welcome! Don't forget to mention my name in the acknowledgement section 😁😁😁
Also please share my videos and channel, help my channel grow (more followers) so I can make more good quality videos!
@@AmeenTopa Yes, I will do it! Waiting for other videos. Also it will be great, if you make a video of how to create a proper foundation in LS-DYNA.
Thankyou Sir. You are a lifesaver. Please make a video on nuclear blast load on a concrete wall.
Good job, are you consider fragmentation ? Thanks
Failure strain was not defined and thus fragmentation was not considered in this model. This is because the damage was not that severe according to the experimental reference.
Thank you very much for excellent tutorial to understand the usage of curve and table keyword as well as blast load. if you provide a tutorial for Johnson cook material model with the above strain rate effect. it will be very useful to the lsdyna beginners like me....
I consider Johnson cook a bit advanced and I would like to keep my tutorials very simple. But, I will keep you comment in mind and maybe in following tutorials will be included.
I would like to learn the basics as well as advances in CAE, Please give me test mail to my mail id selvamraj1@gmail.com
Hello Sir! Your videos are extremely informative and simple to understand. Thank you so much as always! Could you please make a video on simulating rock blasting using LS Dyna and also measurement of ground vibrations generated as the result of the blasting performed.
I already have a series of videos on this topic. You can search in my channel.
Super useful video Ameen. Thank you so much. However, as you spent quite some time defining the strain rate of the material at the beginning of the video, you did not clarify the effects of the strain rate on the results. Thanks again for your useful videos.
You may try the simulation without considering the strain rate effects and see the difference in the results yourself. 😁
Completely agree @@AmeenTopa, but I have one question regarding the strain rate effect, did you use the full stress-strain curve from the beginning of the test or did you choose the data beyond the yield stress?
@@haidermraih2559 for MAT024, we only use the stress data after the yield point. Check this video for a comprehensive explanation about this model: ruclips.net/video/J5Qjj_9Sot0/видео.htmlsi=ovFSlVW0ZyWy1zYG
Like! I did not catch, does this method simulate the action of explosion products? If the charge is located close, then the products of the explosion have a significant effect along with the shock wave.
It depends on the scaled distance. Load blast enhanced is derived from empirical data and it is not suitable for very small values of scaled distance.
For close distance detonations, you need to model the explosive explicitly. Check out my tutorial on TNT Blast on Composite Beam.
@@AmeenTopa Thanks! And I'm just trying to figure out the PARTICAL_BLAST method. I understand that it's the most suitable for this.
It depends on the application and situation. There is no method that is 'best' for everything.
If you are interested in blast with SPH, check out this video here (don't forget to read the video description)
ruclips.net/video/Xidr0p6EplQ/видео.html
Hi Ameen, Thanks for your sharing. Anyways, I have some questions related to this:
1. if the top plate and the core is connected by welding, is it enough by using the same nodes for the connected surface of elements or do we need to define contact surface?
2. if the load is a pressure-time history on the top plate, is it correct if I define segment set (SSID)of the top plate and curve of pressure-time (LCID) and then used it in *LOAD_SEGMENT_SET.
I am new to LS-Prepost, hope you don't mind if my questions don't make any senses. Thank again for your sharing and looking forward for your help.
Dear Lam,
1 - For connection, you can merge the duplicate the nodes which is the easier option. For more advanced modelling, you can use Contacts Tiebreak.
2 - Yes, you can use that approach too. But using Load Blast Enhanced is more accurate because the load varies depends on the incident angle, and this is not possible with Load Segment Set.
Sincerely,
Ameen Topa thanks for your response. I have one more question related to my question 2. We use *LOAD_SEGMENT_SET when the load is a pressure-time curve and *LOAD_NODE_SET when the load is a force-time curve, am I right? And for DEFINE_CURVE, we can use for both pressure or force-time history right? Or are there any other ways? Thanks.
@@lalinlamCambodia Yes, define curve for both, pressure vs time and force vs time curves.
Its great tutorial sir, i wonder to know how to simulate the slope stability (geotechnical for soil and rock mechanics) under blast load (stability of slope affectef by mining blasting activity)? Realy apreciate your help sir..
You can check my other tutorials about blast loads.
@@AmeenTopa where can i check sir? I searched in your youtube chanel its nothing about slope stability under blasting load..
Dear Mr. Topa, thank you for your excellent tutorials for LS DYNA. This one is very useful for me, but I have a question related to the shape of the charge. In your video, you only define the distance of the center of the charge, assuming it was cylindrical. Is there a way to model the shape of the charge since the pressures and impulses around the charge strongly depend on the shape?
To model the initial shape of the charge, you need to use ALE method.
@@AmeenTopa Thanks! Any suggestion about where to look for instructions?
Thanks...ur vdos are mostly useful and easy to practice fr beginers
Thanks a lot! make sure to like and share my videos so more can benefit!
Hi Ameen, may I ask what is your software and hardware configuration that you use for making your videos? For example, which software do you use to record your videos?
I use CAMTASIA software to record my videos. I use Windows 10, Intel (R) Core(TM) i57300HQ CPU with 12.0 GB
Dear Ameen, I also ran the same case, acceleration is very high (unexpected), kindly check your resultant or z acceleration for this simulation. Apart from this, I have tried sandwich foam panel using "crushable foam" as a core and "Steel plate" as a face sheets, the resultant acceleration is upto 10^6-10^5 m/s^2 which is unexpected while displacement is showing satisfactory results. Can you explain this error.
Dear Patil, what do you mean by very high acceleration? This is blast simulation and acceleration is expected to be high.
Good agreement is found when comparing the displacement with test data. Thus it is validated. It is very impractical to measure acceleration in experiment. May I know on what basis you say the acceleration is very high?
@@AmeenTopa Ya agree, you are correct with the test result. But measured acceleration is very high, have you seen acceleration in powers like 3.06 x 10^6 m/s^2 ??? My purpose is to measure resultant acceleration on the panel.
Dear Patil, we are talking about explosives here, right? I don't think it is fair to compare this case of high intensity load (which can deflect a 12 mm thick steel plate) to the case when the target is human body.
1 kg of TNT blasted from a distance of 10 cm, that's crazy amount of force which will shatter human flash into pieces.
Hello, sir. Would you please make a video about the explosion of reinforced concrete? If so, I would be grateful
Sorry, I don't have the time to make any video requests. You can learn how to create blast load from this video. Search on my channel and you will see videos on how to model concrete slab. Combine the steps from both videos and you will get what you want.
With that being said, if you are interested in private consultation session, you can contact my team.
@@AmeenTopa Well, sir, I'm very lucky to meet your video in this world
@@shiqizhang3532 Please share my videos so more people will learn from it!
@@AmeenTopa i will it's wonderful!
Hi Ameen: Is there way to provide cylinder change radius in LS DYNA? I can see you are simulating cylinder as sphere, right?
You mean cylindrical charge, not change, right?
If you want to simulate the shape of the TNT, you must use another method such as ALE or SPH. Check my tutorial TNT Blast on Composite Beam
@@AmeenTopa you are right, Thank you
Nice one brother.
Hi sir, While giving the termination time you have to give in seconds right because in blast enhanced card the units are in kg,m, sec, newton. Please clarify ??
Yes. I am using seconds. And from the unit of length, mass, and stress you can know this also.
www.dynasupport.com/howtos/general/consistent-units
Dear Sir, thank you for the tutorial. I am trying to simulate a storage tank with 100m diameter and 22.5m height under 1500kg TNT blast load based on a paper, so I followed the steps in this video and replaced the plate with a cylinder shell. However, during the solving process, warning messages of "number of blast segment normals pointing away from blast origin = 2570" showed up, and my initial kinetic energy is zero. Can you kindly guide me on this issue? Thank you very much.
My email is lojiahao@hotmail.co.uk if sir wished to contact me through email.
Dear Jia, please check your inbox.
I cannot tell if I don't know more details. You can try to reverse the normals of the segments.
Dear Mr. Topa, I followed your steps on this video precisely only changing the TNT mass to 5kg, it runs smoothly however when I try to plot the Z-displacement graph it showed me just the graph but not any numbers. Can you tell me what's wrong? Thank you
This is just a visualization matter. You need to change the colour of the font or colour or background. You can do it from the setting tabs on the top left of the Prepost window.
@@AmeenTopa The problem is solved, thank you very much. God bless you!
Anyway of obtaining blast reflected pressure from LS-DYNA?
Yes. You can use DATABASE BINARY BLSTFOR
Thank you! Great!
You are welcome. If you are doing research and benefited from this tutorial, please consider citing my article which is given in the video description.
In Blast loading validation of RCC slab, I am defining everything, the unit is in g, mm, ms and MPa in blast load and In MAT I am not defining the unit but all input in LS PRE POST IS according to blast loading unit also the software gives result but the deflection result very small compared to the experiment can you help me? in which definition I missing?
How much small is it?
You can try blast on steel plate or plain concrete slab to check if your units are correct. If this give good results, then it means the problem with how you model the RCC slab.
Excellent work, please keep this up!
https: //ruclips.net/video/GSFXtHi2eJ4/видео.html👍👍👍👍👍👍👍👍👍👍👍👍👍💐
thanks, please share my videos so more people can learn and benefit! :)
you are an education angel :) thanks for everything.
You are welcome
Hello sir, can you do a blast simulation in confined space
For blast in confined space, there will be reflections on the wall. So, you must use ALE method. Check my tutorial on TNT Blast on Composite Beam.
Link to download LS-DYNA:
getintopc.com/softwares/simulators/ls-dyna-free-download/
Can we have manual proportions of materials on this software?
Please help
Like 40% and 20%
Sorry I don't get what you mean.
@@AmeenTopa I mean I have to make a structure of 3 materials in proportion of 40,30 and 30 is it possible to do that?
Polypropylene,mica and rubber in diff proportions in 1 structure
Yes. It is all about the material properties. You need use simple shell or solid elements but you need advanced material model to allow for the anisotropic behavior of the material.
Am getting deflection of plate in same direction of blast load instead of opposite.
Check the normal location of the detonation point.
Can you please share the Excel sheet of stress-strain values for steel?
Please check the link in the video description.
There are errors showing in the file after rechecking the model, they are regarding "load curves are not monotonically increasing, curve 5 is not reaching the same strain value as compared to others", etc. Which result in error termination instead of normal termination. Sir, could you suggest me how to overcome this?
It might be an mistake in defining the curve or in the solver (your software is very old version)
To be honest, I have never faced the error you've mentioned above.
@@AmeenTopa Sir, While rechecking my keywords, this message pops up and I have chosen solid brick elements instead of shell. I recommend, please check your model, too.
@@vaibhavnmete Thank you for your notifiaction
@@AmeenTopa can you please provide your email id on sanj_2sure@yahoo.com or sanjeev222175@gmail.com
can you make the tutorial on blast loading by sph techinique
i need it
have you seen my SPH tutorial? Bird strike simulation.
@@AmeenTopa yes...but that was of impact..how to relate that with blast
@@Nick-gj9my Please check the following paper:
www.dynamore.de/de/download/papers/2012-internationale-ls-dyna-users-conference/documents/blast-impact06-a.pdf
Please send me the download link of ls-dyna full , thanks
Contact the provider of your region to get the license of LS DYNA. You can find more info in their website: www.lstc.com
Link to download LS-DYNA:
getintopc.com/softwares/simulators/ls-dyna-free-download/
hi ammen, could you please help me in the explicit analysis of high speed impact? can i get your mail id?
Write your email here and I will contact you.
bro, the google drive link isn't working
I will try to fix it. For the time being, try this video.
ruclips.net/video/B1vGRU2a5f0/видео.html
Yo tough guy, I fixed the link. Here you go, please don't beat me up 😝😝
drive.google.com/drive/mobile/folders/1i8Upn-Sa4K0I9Zjq-qEClwHahP-dFrbl?usp=drive_open
Link to download LS-DYNA:
getintopc.com/softwares/simulators/ls-dyna-free-download/