How to NUMERICALLY determine Poisson Ratios in

[@sameterkan3892]

Hello Professor, It is a real lecture ! Unfortunately, this information is not conveyed in any school. Thank you for your efforts. Greetings from Turkey

[@MichaelOkereke]

Thanks

[@zainsaeed147]

Very interesting video Dr Okereke

[@MichaelOkereke]

Thanks

[@subratkumarmaharana213]

this is great to see you in camera sir

[@MichaelOkereke]

@Subrat, thanks for your continued interest. I am experimenting with including camera view in my content and lets see how it goes. Cheers!😀

[@joonabil]

Very interesting video

[@MichaelOkereke]

Glad you like it John.

[@dhavalpatel4120]

Hello Micheal how can we download abaqus

[@MichaelOkereke]

Hello @Dhaval, it is not easy to download the full version. You'd need to get a license from 3DS Simulia but this can be very expensive. You'd best get your academic institution to arrange an institution license if that does not exist. However, there is a student license Abaqus for only students enrolled in higher education institution. This is a limited license allowing for only 1000 nodes descretization and it is free. You just search in Google for "Abaqus student license" and you'd be directed to a site to download it. Hope this helps.

[@nanivignesh5194]

Hello Sir, I'm trying to calculate Poisson's ratio for 3D lattice structure (Applied Compression load in Y-axis of 7mm displacement). Bit confused which nodes to be selected for extracting longitudinal and transverse strains. Need your valuable suggestion

[@MichaelOkereke]

Hello @Nani, good question. I will see if I can make a quick video to show this.

[@MichaelOkereke]

Here is the video that can help with this query: kzbin.info/www/bejne/qp6pg2WFnrd-mNk

[@ashfakursalehinlemon]

Suppose, I take two materials in powder form to make a composite consisting of 60% Al2O3 and 40% MgO. How can we calculate the Elastic modulus & Poisson Ratio of the composite in Abaqus? Consider, there is no impurities into Al2O3 and MgO. They are exactly in same size & shape and their operating temperature is also same. Here, Individual Elastic Modulus for MgO= 249 Gpa and individual Elastic Modulus for Al2O3= 7× 10^10 Pa. And Poisson ratio for Mgo=0.35 and Al2O3= 0.22 (for 96% alumina). If it’s not possible to determine in Abaqus, then how can I calculate these two values?

[@MichaelOkereke]

Hello @Ashfakur, I think there are two approaches to doing this; 1. Analytical approach: Here, once you have the volume fraction and properties of each constituent, you can use various mathematical models to determine the effective properties of the composite. These models include rule of mixtures, shear lag model, and Mori-Tanaka model. I will start witht he rule of mixtures and this is for the inverese rule of mixtures appraoch. Of course that will not be as accurate as the Mori-Tanaka models. 2. Computational homogenization method: At times if your constituents are of diverse diameters and distributions, the analytical methods might not be adequate. A computational method would work. You can follow my videos here where I show how to undertake this sort of work. kzbin.info/www/bejne/n3_Hd6JrrdyGqqs&si=EnSIkaIECMiOmarE. At the end, you generate stress-strain plot and from there generate the effective properties based on that. You can use the same model to generate numerically poisson ratio as i showed in this particular video.

[@TM-uf5yv]

Hi Sir, May I know what is the rationale for choosing those 2 nodes for U1 and U2? Thanks!

[@MichaelOkereke]

Hello @TM, thanks for your interest in the channel. I used the periodic boundary conditions on the models of the short fibre composite. As such, only the corner nodes (four in total) can be used to prescribe loading and extract history outputs from the model. So, since I wanted to extract transverse and longitudinal strains, it makes sense to use same nodes to extract the displacement histories in x-axis (U1) and y-axis (U2) directions. So, the data plotted in the video are from those two reference nodes. I hope this explanation makes sense.

[@ichirag_agarwal]

Hello sir! All your videos are amazing and helpful. Currently, I am working on a project where I need to determine the homogenised mechanical prop. of textile weave model exported from TEXGEN software with the use of PBC. I am using ABAQUS for this, can you please make a video on this topic? Also, if you know some reference resources for this, please help. Thank you again for all these tutorials & videos.

[@MichaelOkereke]

Hello Chirag, thanks for your interest in the channel. I am not working yet on textile composites but I do understand the problem you describe. I have some exposure to Texgen but due to certain difficulties with the code, I got my PhD student to develop a different geometry generator and that is the way we have been going. This might be a videos I will come to make in future but for now, I am sorry I am unable to help you with your current query.

[@ichirag_agarwal]

@@MichaelOkereke Okay sir, thank you for the reply. If you know any source or paper where I could find similar analyses, it would be helpful.

[@MichaelOkereke]

Hello Chirag, here is a link to the paper Ambrose (my former PhD student) published on the topic. As part of his work, Ambrose developed a MATLAB-based software for doing similar tasks as Texgen but this is better suited for integration within ABAQUS and subsequent homogenization efforts. You can contact him directly for more insights on this problem. The link to the paper is given here: www.sciencedirect.com/science/article/pii/S0263822319324730 Good luck with your research.