LS-DYNA TUTORIAL 13: Reinforced Concrete and Wrecking Ball

[@Mannabhai_MBBS]

Hello Ameen, you are my inspiration. Because of you, I managed to complete few projects. Please keep up the good work. Your tutorials are really helpful for students like me.

[@AmeenTopa]

Thanks. Please share my videos if you find them useful. :D

[@auliamuhardiarifin8427]

Hello Ameen, i have a question brother, 1. At 08:34, when you defined concrete material in imperial units, i saw that there is an input for units that we can use either MPa, GPa, or Psi (Here you used number 3 for Psi units). My question is,when defining Plastic Kinematic material, why there is no input for units like when defining concrete material? How does LS Dyna understand the unit we want? In my case, i have modeled parts in SI units (milimeters) , and i want to define plastic kinematic material in SI Units too. I know that we should be consistent in units, but i got confused when there is an option for unit input in CSCM concrete material and not in other materials like plastic kinematic. 2. When you defined curve at 21:04 for gravity, how does LS Dyna know that A1 input is time input ? what if i want it otherwise: time input is in O1 and gravity force in is in A1? Is it possible ? Thanks before Amen, your videos are amazing and really helpful !!

[@AmeenTopa]

1. Only few material models have this option. This is because these models are based on empirical data, not constitutive equations. So, software need to know the conversion factor. You need to read and understand about the unit consistency in LS-DYNA. You can look it up in the dynasupport website. 2. The software will understand the curves as follows: x is the time, y is the value of the function which can be velocity, displacement, gravity constant, etc...

[@auliamuhardiarifin8427]

@@AmeenTopa thank you very much !

[@shiqizhang3532]

dear Ameen it's a wonderful video that give me some good idea to finish my work .And hope you get more sim in concrete area!

[@AmeenTopa]

Dear Shiqi, I am glad my videos are helpful. Please share my channel so more people will learn from it. P.S. Don't forget to mention me in the acknowledgement section of your report. :) I have two more examples where I used concrete modelling, you can find them in LS-DYNA BASIC TUTORIALS playlist.

[@shiqizhang3532]

@@AmeenTopa it‘s fine i will give a great thank for you in my master paper or other report if my collage promise thanks again

[@shubhamsharma8867]

The density calculation part of hollow ball is not correct @17:31

[@AmeenTopa]

What's the correct value?

[@덕씨의하루]

Hello my teacher, I made a reinforced concrete model with a TNT explosion, but how do I know if the x-axis time of the curve graph I put in is msec or sec? If there is no fixed unit and the unit I set is SI, do I have to fill in the numbers of all cards in SI units?

[@AmeenTopa]

If all your input in SI units, meaning, if you input the density, mass, stress in SI units, then the time should be in sec, which is the SI unit for time. Take note that your dimensions should be in meters, not millimeters.

[@chetanshenoy941]

Hi Ameen, I am new to LS Dyna.. I am working on a stiffness analysis of a plastic part when it is pushed by a rigid body of 50 mm diameter and 50N force.This analysis I have done in abaqus. Now we have requirement to do the same in LS Dyna and compare with abaqus. Can you please tell me which of your video I can refer to execute in LS Dyna. Or can you tell me which keywords I should use for execution. Thanks.

[@AmeenTopa]

Hi, you can refer to the following tutorial: kzbin.info/www/bejne/oHq4lISua72NaKc But I would recommend you to check the first two tutorials to get used to the user interface of the software.

[@chetanshenoy941]

@@AmeenTopa Hello Ameen, thanks for the reply.. I will go through your videos.. these videos are really helpful..

[@Akash015]

Best video on concrete model! Thanks! Amazing.

[@AmeenTopa]

You are welcome, please share my videos so more people can benefit :)

[@mahaboobsubhani]

Can you do a video on Low-velocity impact on composite materials.

[@AmeenTopa]

Hi Mahboob, yes sure will do in the future. It is in my list of to do vidoes. In the meanwhile, please support this channel and share it to your circles. 😀😀

[@mahaboobsubhani]

@@AmeenTopa Sure, I'll do that.

[@Akash015]

@@AmeenTopa Please do that! Could you do one with confined concrete specimen? Thanks!

[@AmeenTopa]

@@Akash015 Dear Arafat, you can watch my video on compression test. Use SPC SET to apply constraints for the confinement.

[@TấnĐạtPhan-s7c]

Dear Ameen, If I want to model the reinforcement in the remaining direction, should I separate the two layers of reinforcement by shifting them apart?

[@AmeenTopa]

@@TấnĐạtPhan-s7c I don't understand what you mean by "remaining direction". Anyhow, you can follow the same steps (Translate + Copy) to make more reinforcements.

[@TấnĐạtPhan-s7c]

​@@AmeenTopa In this tutorial, you model the Z-direction rebars at a distance of 0.75mm from the surface. If I want to add the X-direction rebars, can I create these rebars at 0.75mm from the surface as well, or should they be at a different distance? Thanks in advance!

[@Perf.kisulsa]

I am now using LS DYNA to analyze the explosion of concrete structures. If you use CONSTRAINED LAGRANGE IN SOLID and put 2 in CTYPE, an error that the node point cannot be shared will occur. I have tried different attempts for a long time without knowing the cause, but I couldn't find the answer. Is there any way to solve this? Can I leave a mail?

[@AmeenTopa]

Leave your email here and I will follow up. In my tutorial, when I first made the reinforcement bars, I translate them and I deleted the original. This is because the original have shared nodes with the concrete. If this is the case, CONSTRAINED LAGRANGE IN SOLID will not work and it is not needed actually. If the nodes are shared between the beams and the solid, that will act like coupling between the two.

[@AmeenTopa]

@@Perf.kisulsa I have sent am email. Kindly check your inbox.

[@shriyaverma2565]

How can we find depth of crack? I have used MAT_072R3 concrete and applied erosion criterion

[@AmeenTopa]

It's not possible to find the depth of crack, unless you use a super fine mesh size.

[@sahilll7694]

Hello sir is there any need to attach beam to sphere because we just want free fall so no need of beam?

[@AmeenTopa]

Yes, because of physics. If there is no beam. Then the ball will fall just straight down and won't hit the beam.

[@yashchordiya5963]

Hey Ameen, thanks for making the video. I have a general question, if I have to check for maximum value of an entity let's say for example displacement. Is there a way to obtain the location of the node as well where the maximum value is actually attained. Because to obtain the maximum value we need to select by part and then the LS-post gives the maximum value in the part, irrespective of the location of node.

[@AmeenTopa]

You can plot the displacement of all the nodes, and from there you can see the maximum displacement. Maximum displacement usually occurs at the midpoint if the supports are at the sides and occurs at the free end in case of a cantilever beam type of boundary conditions.

[@FrankJSun]

Hi, Ameen. Your video is really helpful, thank you for your effort. I have a question about the stress and strain of steel reinforcements. I can obtain the axial force of results from the results, but the stress and strain cannot be output directly. Could you please enlighten me on how to get this information directly from LS-DYNA? Thank you!

[@AmeenTopa]

Hi Frank, first you need to go to Fringe, Beam.

[@shiqizhang3532]

Sir, I used the model of this video and the explosion parameters of that beam. The time display is very long, and I saw through the d3plot file that there are more than ten frames of animation, but no deformation. Is there a problem.

[@AmeenTopa]

Check the unit system in both videos. They must be consistent.

[@shiqizhang3532]

@@AmeenTopa thanks for your solution！

[@shiqizhang3532]

@@AmeenTopa I'm sorry, sir. I gave up the idea of using beam element to simulate reinforcement, because it has never been successful. I plan to use solid element to simulate, so I want to ask, do I need to reserve space for reinforcement in the concrete? If necessary, what method is better? Thank you very much, sir

[@AmeenTopa]

@@shiqizhang3532 If you are not modelling cable/rebar pull out, then it is better to use beam elements. Using solid elements, yes you need to have space inside the concrete to get better results. For slabs or column reinforcement, it is recommended to use CONTRAINED LAGRANGE IN SOLID or CONSTRAINED BEAM IN SOLID. If it didn't work with you, it means you didn't use it correctly.

[@shiqizhang3532]

@@AmeenTopa i got it.i will have a try

[@jinbokchoi3755]

Thank you for your good simulation results. One simple question. How did you find out that it will take 0.4 sec for the ball to hit the wall? Did you calculate it by hands?

[@AmeenTopa]

It is a simple pendulum motion under gravity load. So there is analytical solutions for that.

[@condeo92]

Dear Ameen, Thank you so much for posting these videos especially this one. I have a question in term of modelling the steel rebar. I noticed that you used a plastic kinematic for when you define the rebar. If I wanna see the steel rebar fracture, what would your recommendation be for that material?

[@AmeenTopa]

You may use plastic kinematic and introduce the failure strain as the criteria for fracture.

[@zeinabafshani5577]

Dear Ameen, Thanks a lot for this helpful tutorial. If we use d3crack with mat_CSCM as concrete material, we can see cracks after analysis too, is that ok? or we have use just winfrith model to see cracks correctly?

[@AmeenTopa]

Dear Zeinab, as far as I know, d3crack works only with Winfrith material model.

[@zeinabafshani5577]

Thank you for reply. I tried and it worked on CSCM but just with rigid dropweight. I used mat add erosion on winfrith too, but the result is wrong. actually the ball go through the slab's inner element. do you know how can I solve this?

[@AmeenTopa]

Good to know that, thanks for sharing this info. With regards to your problem, you need to change the contact. I have mentioned about this in this video. kzbin.info/www/bejne/aoezgol5oJp5aaM

[@AmeenTopa]

@CivilAcademia check out this paper www.researchgate.net/publication/331298974_Investigation_of_concrete_material_models_for_analysis_of_seismic_behavior_of_reinforced_concrete_under_reversed_cyclic_load

[@muhammedosman5666]

hi Ameen, I would ask you about composite column. if I want design reinforcement and put steel I-section in a column. how can i contact all elements while there will be an overlap among steel I-section , reinforcement and concrete.

[@AmeenTopa]

Hi Osman, you can try CONSTRAINED LAGRANGE IN SOLID. However, I would recommend that there you make a hollow section in the beam, then apply tiebreak contact or just surface to surface contact with high friction. For the reinforcement bars or stirrups, you can just use the same approach as in this video.

[@muhammedosman5666]

@@AmeenTopa Actually, I'm a master degree student, and my research topic on a composite column with ls dyna software. Is there any chance of having your email address for asking some questions in ls dyna? This is my email (([e-mail])). Thanks for your time and help, you reached me a lot with your videos. I recommended you to my friends and one of them had a talk with you yesterday.

[@Drlutheo]

It is a wonderful example. However, when I tried to represent the model, I found that the rebars are moving out the concrete. I don't know why. I checked the constraints and it is the same with the video. Could you please give me some hints? thank you！

[@AmeenTopa]

You need to fix the end points of the rebars as well. Not only the sides of the slab.

[@Drlutheo]

@@AmeenTopa thank you, I will try your method.

[@Drlutheo]

@@AmeenTopa A little difference in selecting the end nodes makes a great mistake, cool!

[@Drlutheo]

Still, there is another problem. If the rebars are embedded inside the concrete which has no nodes on the side surface of the concrete, should the ends of the rebars be fixed also?

[@AmeenTopa]

@@Drlutheo this problem of rebar falling only happens because I am using DEFORMABLE TO RIGID keyword. If this one is not used, then no need to fix the rebars with SPC SET, the coupling with CONSTRAINED LAGRANGE IN SOLID should be sufficient.

[@sun-yk2mf]

Hello, Mr. Engineer, can you help me with the phenomenon of high speed impact in FML

[@AmeenTopa]

Please reach out to my team via email ([e-mail]) or message me directly on Facebook or LinkedIn.

[@jhumadebnath5836]

Hello, Ameen. Could you please make a video on RC column or beam subjected to blast loading using the MM-ALE method. It should be really really helpful. I am using prepost v.3.2. So, running the new version results in the processor is not possible.

[@AmeenTopa]

You can download and install latest version of the Prepost. It is free. I have already made a tutorial about blast with TNT on composite beam. Please check it in my channel.

[@constructionsite8407]

Dear can you make a video about u shaped brick masonry wall under dynamic loading.

[@AmeenTopa]

Unfortunately, I don't have time to make video requests anymore. This is due to my tight schedule.. With that being said, if you need consultation service, I am available to create the models that you require.

[@Mecharena188]

Hi ameen , how to plot graphs velocity vs time and force vs displacement

[@AmeenTopa]

Check my tutorials: - "How to plot FD diagram" - "Post processing ls pre post "

[@Mecharena188]

@@AmeenTopa thank you sir

[@prashantnanda6680]

Thank you very much for the upload

[@AmeenTopa]

You are welcome! Don't forget to hit the like button and share the video with your circles. :D

[@Mecharena188]

Hi sir , the gravity that you defined is for both or only for ball

[@AmeenTopa]

To define the gravity on all parts in the model, use *LOAD BODY Z (assuming the height is in z direction). If you want the gravity to be for certain parts only, you need to add the keyword *LOAD BODY PARTS and input the part set that will be subjected to gravity in this keyword.

[@Mecharena188]

While applying LOAD BODY Z do we have to change scale factor to -1 or 1?

[@AmeenTopa]

@@Mecharena188 If the height is increasing in your model with the Z axis (meaning: bigger z coordinate = higher location), then you use LOAD BODY Z, and DEFINE CURVE with the gravity constant 9.81 m/s2 as a POSITIVE value.

[@Mecharena188]

Thank you

[@zafertoral5840]

Hello Ameen Topa, I created this model on my computer like same your model. wrecking ball hitted at time 0.4 second and returned. my concrete slab ande rebar had no deformation. ı think, ı mistaked deformable channel but ı controlled and see like your doing.

[@zafertoral5840]

ı solved my problem, ı am sorry for take your time. ı notice my value of R2D=0 :(

[@AmeenTopa]

Great, all the best learning LS-DYNA!!

[@tanishashrestha7053]

Great Content! Thankyou!

[@AmeenTopa]

You are welcome. Please share my videos so that more people can learn 🙂

[@topendraoli9530]

Is it possible to define stress-strain curve on MAT159_CSCM_CONCRETE?. I didn't find any option.

[@AmeenTopa]

I don't think so. MAT159 is a very basic model for concrete. You can use MAT84 to define 8 points of stress strain (pressure vs volumetric strain)

[@topendraoli9530]

Ameen Topa thank you for your quick reply and suggestion

[@AmeenTopa]

You are welcome

[@sabbirsiddique7013]

MAT159_CSCM_CONCRETE has been developed to minimize the input. Other parameters are calculated based on the unit weight and unconfined compressive strength. However, one can customize different parameter as per his/her own requirement in MAT_159_CSCM. The result of such input is actually some sort of stress-strain curve.

[@덕씨의하루]

thank Ameen, entered the concrete density as 2.246e-04, what would be the unit for this? If the original concrete unit is set to kg/mm³, it would be 2.4*10^6 kg/mm³. Did they multiply all card values by *10^2? Was the rebar density also multiplied by *10^2, resulting in 7.2e-04? If I’m correct, why do they apply *10^2 instead of using the original kg/mm³ unit? Ameen, you are my savior. Please, I’m begging you. 😭

[@AmeenTopa]

@@덕씨의하루 in this example, I also used imperial unit system (pound, inch, PSI), and I use that only for demonstration because I never used imperial unit system in any other video.

[@clarababy6872]

Dear Ameen, I tried applying this gravity load in z direction by applying it in Body Z, because that's the direction I wanted the the ball to fall in. But it didnt make any difference to the ball. Then I applied it in Y (Body y) direction and it worked. Can you explain what happened/did you understand my situation?

[@AmeenTopa]

Are you following the same tutorial? The ball might be constrained in the other directions, that's why it won't go except in the direct which we allow it to move.

[@clarababy6872]

@@AmeenTopa I was appying gravity, to another model. But other time I tried it worked. Kind of confused now what happened. But now its working. Thank you so much.

[@AmeenTopa]

Glad you figure it out.

[@msc.str.engineermohammedad4269]

@@clarababy6872 please would you mind if you give me your email in order to ask you about my case which is like your

[@ethiofunentertainment6006]

hi Amen thank u for the video. can u please send me keywords how to rollover

[@AmeenTopa]

Sorry, it was a very old file. I don't have it anymore.

[@keoagilekerileng663]

Dear Amee, Thank you for this valuable Tutorial, I tried to help someone with the skills acquired from here, How do I solve the issue of this error message "Material 159 part number 1 failure curve parameters are inconsistent,alpha should be greater than gamma" I used MAT_159 CSCM CONCRETE, and please can you clarify the difference this current and MAT_159 CSCM

[@AmeenTopa]

You can read right? The error says alpha should be bigger than gamma. So, it means you defined gamma bigger than alpha. MAT159 CSCM is more advanced than MAT159 CSCM CONCRETE. They use the same constitutive equations, but in MAT159 CSCM CONCRETE, all the properties are automatically generated.

[@keoagilekerileng663]

@@AmeenTopa Thank you very much. I couldn't find alpha and gamma are in MAT159 CSCM CONCRETE I only saw in MAT159 CSCM

[@keoagilekerileng663]

Where exactly this parameters are situated

[@VivekKumar-mh3zh]

Sir, please make or share a video on Steel Structures.

[@AmeenTopa]

I have a video on Blast on steel plate. Check that one out!

[@dhaferb]

hv you link for download sftwr plz , thnak s

[@AmeenTopa]

No.

[@덕씨의하루]

You said q=d3crack, but could you tell me how to do it with the current version instead of the old version? Please, I am a self-taught student in Korea😂

[@AmeenTopa]

@@덕씨의하루 do you mean you use LS-RUN? If so, then you can add this command in the expression line.

[@덕씨의하루]

I typed "$SOVER" i=$INPUT ncpu=$NCPU memory=$MEMORY Q=d3crack, and the d3crack file size is 0. What should I do, teacher😢

[@AmeenTopa]

@@덕씨의하루 have you defined DATABASE BINARY D3CRACK? Also, this crack file is supported only with MAT WINFRITH.

[@quoctobao3057]

Dear Ameen The model don't have any problems when used 072R3-CONCRETE DAMAGE REL3 Material. When I change to become 159 CSCM Concrete or 084 WINFRITH CONCRETE REINFORCEMENT , The model have errors that can not completely run. Could you give me your email?

[@AmeenTopa]

Dear Quoc, 084 WINFRITH CONCRETE REINFORCEMENT material model should be used with 084 WINFRITH CONCRETE. It is a method to model the reinforcement without having to create the rebars. Put your email here and I will follow up in my free time.

[@quoctobao3057]

@@AmeenTopa this is my email: [e-mail] I hope to receive your email. Thank you so much.

[@constructionsite8407]

brother make video for brickwall modeling..

[@AmeenTopa]

I am working on a paper in that topic. Once the publication is done, I will make one video

[@constructionsite8407]

@@AmeenTopa Sir , when will paper be published

[@AmeenTopa]

@@constructionsite8407 It is not up to me. I have to wait for the reviewers. :D

[@constructionsite8407]

@@AmeenTopa It means work is done..Best of luck

[@liwang8792]

8.35

[@AmeenTopa]

8.35?

[@Jimmy-qt7gc]

Nice video sir .. Can i hv ur email?

[@AmeenTopa]

Drop your email here and I will follow up.

[@Jimmy-qt7gc]

@@AmeenTopa [e-mail]