Hello sir.Very glad that i came across this. It would be awesome if you shed some light on multi scale modelling of nano comp in upcoming vid.Thank you!!!
Though you had explained reference point for defining displacements, I have not understood the importance of it. At what position should the ref. point be fixed? And Could you suggest a source to learn finding effective mechanical properties of a woven fabric composite? Looking forward to hearing from you. Thanks, Shravan
Hello @Shravan Bhadoria, thanks for your interest in the channel. The reference point makes it easy for one to determine stress-strain plot on a model since you are only having to track parameters as force and displacement only in one point. The other way to do it is to use volume averaging where you have to write to history all properties for all elements in the model. If the model has a million elements, most student computers might not be able to handle that. To prevent that happening, you then use the constraint equation to tie the model (face) to a reference point anywhere in the model. It means that the behavioru of the reference point will be constrained to whatever is happening in the whole model. This way, you can conveniently track the history of that reference point as representative of the history of the whole model. It is the principle of Newton's third law of motion, where equal reaction initiates and equal force. So, the reference point is reacting to what is going on or the forces in the material. Provided the constraint equation exists, this is correct. On resource material for woven fabric composites, I have actually not done a video on this on the channel but plan to. I have though an online course that I have developed which can help you. If you are interested in ths, then join my CM Videos Insider Group via cmvig.cmvideos.org and you will be able to contact me directly and then I can share this resource with you.
Sorry Dr. Michael for the delayed response. More importantly thanks for the time and explanation on the reference point. I had joined that group mentioned above. Looking forward to learn more from you.
Thank you very much, Dr. Michael, for these good lectures. I have a question. How do I determine the volumetric fraction of two materials in the case of preparing a slide or layer consisting of polymeric material and fibers at rates of 30% and 70% in the Abaqus program? Is there an explanatory video available?
Hello, thanks for your comment. I am a bit unsure about what the question is about. If you want to determine the volume fraction of two materials (composites), you can do so by finding the weight contribution of each of the phases that make up the system. The weights of say E-glass fibre and the weight of the matrix, say Epoxy. With those weights, you define the weight fractions. You also need to know the densities of the constituents that make up the composite. If you want to see how to make the conversions, a quick google search will help you as you can see from here: sites.google.com/site/compositematerialsdesign/home/weight-and-volume-fractions. I am not sure if this is what you are looking for. Good luck with the research.
Again, this tutorial is out of this world. Dr.Michael, thanks once again. but I wonder how you calculated those effective mechanical properties(Effective modulus and effective strength)? appreciated!
Hello @PEEK CF, thanks for your kind comments. It was quite easy to calculate the effective properties. I have included in the description of the video downloadable resources (with the Spreadsheet I used) which shows you how to calculate it. I hope you found it helpful and if you have anymore questions, I will be happy to answer them.
you should put plastic properties of glass fibre and Von Mises stress is used for the metal and isotropic materials at most situations, which can not represent the stress state of composites with anisotropic properties.
Not sure I understand or agree. Von Mises stress works generally as it is an effective (average state of stress). The Glass fibre studies here is essentially isotropic and the matrix as well so for such RVE (micromechanical) modelling, it is okay to represent them as I have seen. If you are doing a laminate analysis, then you can incorporate the required anisotropic properties of the laminates. Maybe, I have not understood your comment properly.
@MichaelOkereke thanks for the excellent tutorial, i would like to try the same for the compression, in that case just reversing the magnitude is sufficient, else do we need to modify the constraint equations and RP
@MichaelOkereke in this tutorial, after the RVE modelling if I want to apply PBC for this, is it appropriate to create a set by selecting the surface nodes in XFront, Xback; YTop, YBase; ZFront,Zback and constraint that using the Equations?, I am trying to perform 1) 2D RVE-PBC compression 2) 3D RVE-PBC compression
Yes you can do what you suggested but it would be simply RVE Modelling but not PBC. For the later, it involves a different node to node *Equations. Cheers.
Dr.Michael, thanks for your video. I ran into a problem: I made the model following each step in the video, but after submitting the job, it showed: "too many attempts made for this increment." I wonder if you can help me find out why.
Hello @Ali Peei, thanks for your interest. It is difficult to know for sure what is the reason for this problem. It could be you need to check the input values you used in your material library. It could also be that your loading is too much and so the simulaiton is struggling to converge at those large loads. I can only know by looking into the specific model setup and try and see what is going on. Good luck with the research. If you are a member of my CM Videos Insider Group (cmvig.cmvideos.org), then you can contact me directly there.
Thanks for another wonderful video, Dr. Michael. I have one question, what kind of situation does this boundary conditions represent? I with 3 faces symmetric and 3 faces free.
Hello @Haowei Huang, this is a good question. It is the standard boundary condition to use when you are working with a representative volume element and you want to simulate a uniaxial case. Think about it like this, if you have the full specimen model, and you hold the back and pull the front, what will normally happen is that the system will be free to move uniaxially at the held points but in the centre of the model, since there is no constraint on it, it will start showing a necking/narrowing deformation. This means, not every part of the system is experiencing a uniaxial deformation. The solution (for a 2D case) is to then isolate the original model into four quadrants, then for one of the quadrant, impose the type of boundary condition I have shown here. This means you will ensure every part of the model under deformation is seeing a pure (true) uniaxial deformation. As such, you can then compare the model predictions directly with a macroscale/structural level experiment. I hope this makes sense.
Hello @Masfikun Mahim, I am not sure I understand the question. If you want to get the homogenized elastic properties of the RVE of this bidirectional composite, then I addressed this already from minute 35:00 of this videos. Once you generate the stress-strain plot, the elastic properites is the slope of the elastic region and similarly the effective strength (or yield stress), I have defined here as the global (absolute) maximum of the stress-strain plot. You can follow the discussion directly via this link: th-cam.com/video/zHUC0cVkdVM/w-d-xo.html If I have mistaken and you are looking for something else, then do then me. Good luck with the research.
Hello @Aslam Sajad, thanks for your interest in the channel. It is funny you ask because I am thinking of making this exact video. Please watch out for it in the next couple of videos that I will be making. Cheers!
The effective properties were calculated simply from the stress-strain plot. Young's Modulus is the slope (in linear region) of a stress-strain plot while the Strength is the first maximum for the stress data. If you download the excel file referenced, you can see how I did this for this simulation.
Hello @Masfikun, I am not sure about doing this at RVE modelling scale. It can be done from the principle of Direct Stiffness Method. I have an extensive discussion of this in my textbook (see Chapter 3) where you can learn about this. Here is a link to the textbook: link.springer.com/book/10.1007/978-3-319-67125-3
Hello, I have to Google-translate your comment to understand what you are asking about. Hope the google translation is the content of your comment? Thanks for your kind comments. I can do the suggested, by creating a mixed fibre or mixed particulate composite. If you can give me more description of the problem, then I will investigate.
"3D FEM simulation of mechanical property of composites reinforced by both particles and fibers" This is a very early literature on hybrid enhancement, I have a strong curiosity about his modeling process, and sincerely hope that you can help me. Unfortunately, this is a Chinese document, and I think you may need some translation software to understand it. It would be appreciated if you could help me. By the way, you are the best teacher I have ever met, in the past, I was not able to use this software because of the country, in our country idiom it is "see each other and hate to be late". Thank you very much for sharing your previous videos, you are a great person.@@MichaelOkereke
Hello, thanks for your kind comment. Unfortunately, I am not able to speak or understand Chinese but can as you said use google translate or some other software to read the paper. I will still want you to send me a copy of the paper if you have it. It seems the authors uploaded it to ResearchGate but there is no downloadable copy. Searching on Google Scholar, the paper exists but when I click the link, it says a firewall is blocking access. You might just email me a copy of the paper to my email which you can find in the About section on this channel or by subscribing to my newsletter on: cmvig.cmvideos.org I will like to read the paper and see if there is any way I can help.
Sorry, because I have some things to attend to lately, and I'm busy, so I just saw your reply. I am currently translating it into English and will be sending you the translated version shortly, thank you very much for your help, you are the most knowledgeable person I have ever met, and you have been of great help to me. @@MichaelOkereke
Dear Dr. Michael, is it possible to get the script , you mentioned in your tutorial it can be downloaded but there is no such information. Please, thank you so much!
Hello @Maths Plus CAE, I am sorry about this. That was the wrong link and I have now changed it. So, go tot he video description section and see the actual link or just click this: bit.ly/3p0M2RP I hope this works for you and apologies for the putting the wrong link.
I saw your RVE simulation for the bidirectional composite material, and it sparked my interest. I was also working on a composite material reinforced with plan wave fabric. It was extremely difficult for me to create the dry fiber fabric with Abaqus. However, I did it with TexGen software and meshed it with this software before exporting it as a stp file to simulate with Abaqus software. But I find it tough to simulate. And, once again, I imported the TexGen stp file into Abaqus and followed the steps in the video which you posted for the bidirectional laminated composite, but it is still not converged and message an error. How might you assist me with this? Can I provide you with the 3D drawing of the fabric and the matrix that I did for the RVE and can you help me if you see it? I hope you will solve my problem.
Hello @Endalkachew, thanks for this comment. It is definitely difficult making such models. I will hope to make some videos in future about woven composites. Good luck with the research.
Hello Vituko, thanks for your interest in the channel. The answer is sort of No, especially if you set it up as I did here. However, if you choose a different RVE, then yes. You have to come up with an RVE that has a beam geometry and adjust your boundary conditions accordingly. For your beam study, I do think you should do a microscale study first using the approach described here. It will give you properties that can serve as input to a higher length scale study which can be your macroscale beam model. This is the so called micro-macroscale modelling approach.
SIR, I am running a similar RVE simulation problem having 4% Vf of backing fibers in the tensile load direction and 50% Vf of fibers in trasnsverse direction to replicate GFRP NCF Composite.I am using PBCs with node to node implementation. Experimentally i got two slopes in Stress strain curve but computationally i am getting a straight line only. Can u please help me sir.
Hello @ME21D002, I am not sure why you are getting a single plot from your computational work. If you are combining two loads, then you should get two plots. It is a bit unclear what your question is. I will reply your email where you have provided more details. Thanks.
Hello @Hiten Singh, definitely, I could easily have done the case for 0/45/90 laminates but I didn't because this video was merely for a bidirectional composite. The case you cite here could be classed under an multidirectional composite. That could be a video idea for the future but the same principles in this video will also apply for that.
Hello Anitta, thanks for your interest in the channel. I apologize for missing out on uploading the python codes. I have now included it in the description section of the video, so please go and download it. Thanks.
Hello @Arpit Panwar, I did not use PBC here as the code for doing this is not available yet for viewers on this channel. I wanted to create a modelling approach that anyone can use. Ideally, a PBC-style solution will be better but we are not yet there in our journey in this channel. Once I have made the series of videos about PBCs in 3D and show how this can be done, I will be making further videos where I show how PBCs can be used for 3D domains for different materials and clearly this will be the case for this BD Composite. I will just ask that you keep watching till when those videos become available.
Hello Nag, thanks for your interest in the channel. I am really confused by your query, as I have a mesh on the model. Please can you explain more what your query is about?
Hello Dr Okereke! Really inspiring! very helpful video! I have some questions on a project I am currently working and I would really need to ask a few questions about a similar problem! Is it possible I can send you an email? Thanks in advance in any case! :)
Hello, thanks for your interest in the channel. Please you can get in touch via my CM Videos Insider Group through this link: cmvig.cmvideos.org/ You will be able to reach me from the welcome email.
I learned lots of useful information from this video as an engineer and academician. Thanks so much to share the video with us.
Glad it was helpful Mehmet.
Very interesting video thanks from Algeria.
Our pleasure!
Hello sir.Very glad that i came across this. It would be awesome if you shed some light on multi scale modelling of nano comp in upcoming vid.Thank you!!!
Hi Abdul, definitely would consider doing so in future videos. Thanks for your interest in the channel.
Thanks Dr. Michael.
Though you had explained reference point for defining displacements, I have not understood the importance of it. At what position should the ref. point be fixed? And Could you suggest a source to learn finding effective mechanical properties of a woven fabric composite?
Looking forward to hearing from you.
Thanks,
Shravan
Hello @Shravan Bhadoria, thanks for your interest in the channel. The reference point makes it easy for one to determine stress-strain plot on a model since you are only having to track parameters as force and displacement only in one point. The other way to do it is to use volume averaging where you have to write to history all properties for all elements in the model. If the model has a million elements, most student computers might not be able to handle that. To prevent that happening, you then use the constraint equation to tie the model (face) to a reference point anywhere in the model. It means that the behavioru of the reference point will be constrained to whatever is happening in the whole model. This way, you can conveniently track the history of that reference point as representative of the history of the whole model. It is the principle of Newton's third law of motion, where equal reaction initiates and equal force. So, the reference point is reacting to what is going on or the forces in the material. Provided the constraint equation exists, this is correct.
On resource material for woven fabric composites, I have actually not done a video on this on the channel but plan to. I have though an online course that I have developed which can help you. If you are interested in ths, then join my CM Videos Insider Group via cmvig.cmvideos.org and you will be able to contact me directly and then I can share this resource with you.
Sorry Dr. Michael for the delayed response. More importantly thanks for the time and explanation on the reference point.
I had joined that group mentioned above. Looking forward to learn more from you.
Thank you very much, Dr. Michael, for these good lectures. I have a question. How do I determine the volumetric fraction of two materials in the case of preparing a slide or layer consisting of polymeric material and fibers at rates of 30% and 70% in the Abaqus program? Is there an explanatory video available?
Hello, thanks for your comment. I am a bit unsure about what the question is about. If you want to determine the volume fraction of two materials (composites), you can do so by finding the weight contribution of each of the phases that make up the system. The weights of say E-glass fibre and the weight of the matrix, say Epoxy. With those weights, you define the weight fractions. You also need to know the densities of the constituents that make up the composite. If you want to see how to make the conversions, a quick google search will help you as you can see from here: sites.google.com/site/compositematerialsdesign/home/weight-and-volume-fractions. I am not sure if this is what you are looking for. Good luck with the research.
Again, this tutorial is out of this world. Dr.Michael, thanks once again. but I wonder how you calculated those effective mechanical properties(Effective modulus and effective strength)? appreciated!
Hello @PEEK CF, thanks for your kind comments. It was quite easy to calculate the effective properties. I have included in the description of the video downloadable resources (with the Spreadsheet I used) which shows you how to calculate it. I hope you found it helpful and if you have anymore questions, I will be happy to answer them.
you should put plastic properties of glass fibre
and Von Mises stress is used for the metal and isotropic materials at most situations, which can not represent the stress state of composites with anisotropic properties.
Not sure I understand or agree. Von Mises stress works generally as it is an effective (average state of stress). The Glass fibre studies here is essentially isotropic and the matrix as well so for such RVE (micromechanical) modelling, it is okay to represent them as I have seen. If you are doing a laminate analysis, then you can incorporate the required anisotropic properties of the laminates. Maybe, I have not understood your comment properly.
VERY insightful sir
Thanks Subrat... glad you liked it.
@MichaelOkereke thanks for the excellent tutorial, i would like to try the same for the compression, in that case just reversing the magnitude is sufficient, else do we need to modify the constraint equations and RP
Hello, normally yes, reversing the direction of the load is enough to get it in compression, except you want to do something fancy.
@MichaelOkereke in this tutorial, after the RVE modelling if I want to apply PBC for this, is it appropriate to create a set by selecting the surface nodes in XFront, Xback; YTop, YBase; ZFront,Zback and constraint that using the Equations?, I am trying to perform 1) 2D RVE-PBC compression 2) 3D RVE-PBC compression
Yes you can do what you suggested but it would be simply RVE Modelling but not PBC. For the later, it involves a different node to node *Equations. Cheers.
Dr.Michael, thanks for your video. I ran into a problem: I made the model following each step in the video, but after submitting the job, it showed: "too many attempts made for this increment." I wonder if you can help me find out why.
Hello @Ali Peei, thanks for your interest. It is difficult to know for sure what is the reason for this problem. It could be you need to check the input values you used in your material library. It could also be that your loading is too much and so the simulaiton is struggling to converge at those large loads. I can only know by looking into the specific model setup and try and see what is going on. Good luck with the research. If you are a member of my CM Videos Insider Group (cmvig.cmvideos.org), then you can contact me directly there.
Thanks for another wonderful video, Dr. Michael. I have one question, what kind of situation does this boundary conditions represent? I with 3 faces symmetric and 3 faces free.
Hello @Haowei Huang, this is a good question. It is the standard boundary condition to use when you are working with a representative volume element and you want to simulate a uniaxial case. Think about it like this, if you have the full specimen model, and you hold the back and pull the front, what will normally happen is that the system will be free to move uniaxially at the held points but in the centre of the model, since there is no constraint on it, it will start showing a necking/narrowing deformation. This means, not every part of the system is experiencing a uniaxial deformation.
The solution (for a 2D case) is to then isolate the original model into four quadrants, then for one of the quadrant, impose the type of boundary condition I have shown here. This means you will ensure every part of the model under deformation is seeing a pure (true) uniaxial deformation. As such, you can then compare the model predictions directly with a macroscale/structural level experiment. I hope this makes sense.
I have fibre epoxy perameter & matrix perameter how can i generate elastic propertics from rve modeling. I tried easy PBC. But can’t get the solution
Hello @Masfikun Mahim, I am not sure I understand the question. If you want to get the homogenized elastic properties of the RVE of this bidirectional composite, then I addressed this already from minute 35:00 of this videos. Once you generate the stress-strain plot, the elastic properites is the slope of the elastic region and similarly the effective strength (or yield stress), I have defined here as the global (absolute) maximum of the stress-strain plot. You can follow the discussion directly via this link: th-cam.com/video/zHUC0cVkdVM/w-d-xo.html
If I have mistaken and you are looking for something else, then do then me. Good luck with the research.
Thanks a lot sir🤗, can you do a video on non-straight fibers...it would be really helpful..
Hello @Aslam Sajad, thanks for your interest in the channel. It is funny you ask because I am thinking of making this exact video. Please watch out for it in the next couple of videos that I will be making. Cheers!
How did you calculate effective properties
The effective properties were calculated simply from the stress-strain plot. Young's Modulus is the slope (in linear region) of a stress-strain plot while the Strength is the first maximum for the stress data. If you download the excel file referenced, you can see how I did this for this simulation.
how to find stiffness matrix of a structure (preferably in RVE modelling) in Abaqus?
Hello @Masfikun, I am not sure about doing this at RVE modelling scale. It can be done from the principle of Direct Stiffness Method. I have an extensive discussion of this in my textbook (see Chapter 3) where you can learn about this. Here is a link to the textbook: link.springer.com/book/10.1007/978-3-319-67125-3
Sir, request you to please make one video on how to find the fibers cordinates by using Monte Carlo simulation.
Hello Nag I will think about it... and in future see if I can make a video about it.
非常感谢您的分享，您的视频在中国非常受欢迎，我想问一下您是否会在不久的将来更新带有混合纤维和颗粒的RVE模型上的视频
Hello, I have to Google-translate your comment to understand what you are asking about. Hope the google translation is the content of your comment?
Thanks for your kind comments. I can do the suggested, by creating a mixed fibre or mixed particulate composite. If you can give me more description of the problem, then I will investigate.
"3D FEM simulation of mechanical property of composites reinforced by both particles and fibers" This is a very early literature on hybrid enhancement, I have a strong curiosity about his modeling process, and sincerely hope that you can help me. Unfortunately, this is a Chinese document, and I think you may need some translation software to understand it. It would be appreciated if you could help me. By the way, you are the best teacher I have ever met, in the past, I was not able to use this software because of the country, in our country idiom it is "see each other and hate to be late". Thank you very much for sharing your previous videos, you are a great person.@@MichaelOkereke
Hello, thanks for your kind comment. Unfortunately, I am not able to speak or understand Chinese but can as you said use google translate or some other software to read the paper. I will still want you to send me a copy of the paper if you have it. It seems the authors uploaded it to ResearchGate but there is no downloadable copy. Searching on Google Scholar, the paper exists but when I click the link, it says a firewall is blocking access.
You might just email me a copy of the paper to my email which you can find in the About section on this channel or by subscribing to my newsletter on: cmvig.cmvideos.org
I will like to read the paper and see if there is any way I can help.
Sorry, because I have some things to attend to lately, and I'm busy, so I just saw your reply. I am currently translating it into English and will be sending you the translated version shortly, thank you very much for your help, you are the most knowledgeable person I have ever met, and you have been of great help to me.
@@MichaelOkereke
Dear Dr. Michael, is it possible to get the script , you mentioned in your tutorial it can be downloaded but there is no such information. Please, thank you so much!
Hello @Maths Plus CAE, I am sorry about this. That was the wrong link and I have now changed it. So, go tot he video description section and see the actual link or just click this: bit.ly/3p0M2RP
I hope this works for you and apologies for the putting the wrong link.
I saw your RVE simulation for the bidirectional composite material, and it sparked my interest. I was also working on a composite material reinforced with plan wave fabric. It was extremely difficult for me to create the dry fiber fabric with Abaqus. However, I did it with TexGen software and meshed it with this software before exporting it as a stp file to simulate with Abaqus software. But I find it tough to simulate. And, once again, I imported the TexGen stp file into Abaqus and followed the steps in the video which you posted for the bidirectional laminated composite, but it is still not converged and message an error. How might you assist me with this? Can I provide you with the 3D drawing of the fabric and the matrix that I did for the RVE and can you help me if you see it? I hope you will solve my problem.
Hello @Endalkachew, thanks for this comment. It is definitely difficult making such models. I will hope to make some videos in future about woven composites. Good luck with the research.
@@MichaelOkereke Thanks, Dr. Michael. hopefully, you will do it.
Hello sir, is it possible to perform compression and hardness test on MMCs using ABAQUS?
Hello Whis, definitely you can do those tests. You have to set it up properly.
Hello Dr. Michael, is it possible to use the RVE to model the properties of a whole beam?
Hello Vituko, thanks for your interest in the channel. The answer is sort of No, especially if you set it up as I did here. However, if you choose a different RVE, then yes. You have to come up with an RVE that has a beam geometry and adjust your boundary conditions accordingly.
For your beam study, I do think you should do a microscale study first using the approach described here. It will give you properties that can serve as input to a higher length scale study which can be your macroscale beam model.
This is the so called micro-macroscale modelling approach.
SIR, I am running a similar RVE simulation problem having 4% Vf of backing fibers in the tensile load direction and 50% Vf of fibers in trasnsverse direction to replicate GFRP NCF Composite.I am using PBCs with node to node implementation. Experimentally i got two slopes in Stress strain curve but computationally i am getting a straight line only. Can u please help me sir.
Sir, i will be waiting for your reply
Hello @ME21D002, I am not sure why you are getting a single plot from your computational work. If you are combining two loads, then you should get two plots. It is a bit unclear what your question is. I will reply your email where you have provided more details. Thanks.
Nice video thank you professor but I want to know for fibre reinforced laminates is it possible to make 0,45 and 90degree instead of 0/90/90/0 ??
Hello @Hiten Singh, definitely, I could easily have done the case for 0/45/90 laminates but I didn't because this video was merely for a bidirectional composite. The case you cite here could be classed under an multidirectional composite. That could be a video idea for the future but the same principles in this video will also apply for that.
Thank you professor.
Hello Dr. Okereke, where can find the python code for the models?
Hello Anitta, thanks for your interest in the channel. I apologize for missing out on uploading the python codes. I have now included it in the description section of the video, so please go and download it. Thanks.
@@MichaelOkereke Thank you very much Dr. Okereke!
Sir, Why did we not apply PBC in this model?
Hello @Arpit Panwar, I did not use PBC here as the code for doing this is not available yet for viewers on this channel. I wanted to create a modelling approach that anyone can use. Ideally, a PBC-style solution will be better but we are not yet there in our journey in this channel. Once I have made the series of videos about PBCs in 3D and show how this can be done, I will be making further videos where I show how PBCs can be used for 3D domains for different materials and clearly this will be the case for this BD Composite. I will just ask that you keep watching till when those videos become available.
Sir please also add mesh in this bidirectional RVE modeling.
Hello Nag, thanks for your interest in the channel. I am really confused by your query, as I have a mesh on the model. Please can you explain more what your query is about?
Sir, please take the woven fiber as a layer in the same problem. 🙏
Hello Nag, does your query relate to woven composites?
@@MichaelOkereke yes sir
Hello Dr Okereke! Really inspiring! very helpful video! I have some questions on a project I am currently working and I would really need to ask a few questions about a similar problem! Is it possible I can send you an email? Thanks in advance in any case! :)
Hello, thanks for your interest in the channel. Please you can get in touch via my CM Videos Insider Group through this link: cmvig.cmvideos.org/
You will be able to reach me from the welcome email.
@@MichaelOkereke thank you very much for your answer Dr! Looking forward to discuss further!