LS Dyna

LS Dyna

Thermal aspects during Turning operation

    • MAMIN219
      Subscriber

      @peteroznewman Sir I have searched so many times for accepted answer but I didn't get it. once again sorry for that I have also tried @Rob sir's approach but still not finding yet. May be I have started with new discussion so may be this is not occurring now, I am trying here my doubt as Ask a Question according to @Kremella sir's guidance.


      @peteroznewman Sir i have tried with 12 mm tool travel nut still my tool is not travelling

      and actually distance between that two vertex is 6.8 mm which you have mentioned in last discussion.

    • Kp_9079
      Subscriber
      Sir ni saw file , in that if the tool was moving then why there is no removal of material from the workpiece ( chip formation) ? n
    • peteroznewman
      Subscriber
      @MAMIN219,  The tool did travel 2 mm.nI already answered this question in your other post. Look at the last post I made on Page 1.n

      After your suggestions I am stating new discussion here,Respected sir @peteroznewman Thank you for your wonderful suggestion on 'PTC Mathcad Prime',1)Sir actually we are trying to shift the tool 0.7mm towards the workpiece so that we don't have to give the depth of cut (that is the x -component ) , but we could not make it . So if possible can you shift the tool 0.7mm and send us back the file by making the changes . Sir these is my final file with appropriate boundary condition That is depth of cut =0.7 mm Feed = 0.4 mm per revolution Rpm = 350 Workpiece dia = 23 mm End time = 1.364 as per your previous calculation Similarly cutting velocity = as per your calculationAngular velocity = as per your calculationSince we need to have 50 revolution which means 50*360 = 18000 ( please check that it is right )  NOTE: Please check my Remote displacement all data and also check global coordinate along with all the selection of faces which i have selected in below ansys 2020 R1.So sir please take a look at my file and let me know if i have made any mistake soo that i can finally start with my simulation as soon as possible https://us.v-cdn.net/6032193/uploads/WO5RUUJQ7GV5/image.pnghttps://drive.google.com/file/d/1wCKeaeudjwGROy7uAYgOVcsqCFu_hjDQ/view?usp=drive_webhttps://forum.ansys.com/discussion/20942/regarding-previous-turning-operation-and-checking-of-parameter-in-ansys-2020-r1-file

      The problem is the tool is 6,802.3 mm wide in Mechanical. That is 1,000 times larger than it is in SolidWorks. Clearly there is a scale error in importing the geometry, so moving 2 mm is not easy to see.n @Kp_9079, The size of the element is enormous compared with 2 mm so there is not enough penetration to remove any material.n You can measure the distance between vertices and the measurement shows up on the bottom of the window.n
    • MAMIN219
      Subscriber
      Respected sir ArraynWell , sorry for disturbing you number of times ,nHowever I am trying these simulation from the past 1 month and following your proper guidance , still i am not able to achieve the movement of the tool , and consequently chip formation .nSo sir please can you guide me where I am making mistake , so that i can successfully achieve my target.nI have also performed this data in ANSYS 2020 R2 but Here I am sending ANSYS 2019 file so please check this file and send feedback with us so we can get clear idea about it and also this simulation is too much time taking so what can i do for reduce time .nI have applied automatic mass scaling option 'Yes nplease guide me and simulate this file if any mistake . so that I can understand where i am mistaking in My simulation. Once again Thank you ArraySir nArrayfor always replying my post with clear clarification.nGive regards,nMihir Aminn
    • MAMIN219
      Subscriber
      Respected sir ,nPlease Give answer,nWhat can I do to simulate this result as fast as possible nRefer my previous file and Question and please answer me as soon as possiblennGive regards, nMihir Aminn
    • peteroznewman
      Subscriber
      I can't run your model in ANSYS 19.2 because it exceeds the Student License limit.nI'm about to start running your model in ANSYS 2020 R1. I would then see how it looks after 24 hours.nThe zip file was attached two days ago. Please reply with your results after 48 hours of compute time.nYou ask how to get the results as fast as possible. I told you before to check Characteristic Length. Did you plot the Characteristic Length for your mesh? nThe minimum Characteristic Length is 0.025 mmnThe most of the elements you will be cutting initially have a CL of about 0.125 mm.nCan you see how it would be possible to make a mesh where the minimum CL was 0.125 mm instead of 0.025 mm? That would mean the maximum time step could be 5 times larger, cutting the solution time by a factor of 5.nUnder Analysis Settings, Output Controls, you set Result Number of Points to 20. That number is too small to see a good animation of the model. Set it to 2000.n
    • peteroznewman
      Subscriber
      By modifying the geometry, I can increase the minimum CL length to 0.1 mm, which is 4 times faster than what you had.nOne mistake in your model is that the Angular Velocity and the Remote Displacement rotation are both positive, but the correct direction of the tool is to have these be negative.nOne problem with your model is the workpiece material is a linear elastic material. If you don't use an Explicit Dynamics material with some failure criteria, then you should add a Plasticity material model so the material can flow and fail by meeting the Total Strain criterion.n
    • MAMIN219
      Subscriber
      Thank you so much for perfect clarification of my doubt. nI am really thankful for your valuable comments and feedback as well as motivation with projects by giving Valuable answer.I have also tried plot but didn't understand properly that's why I have asked regarding that. Now I have clear clarifications on that. n Right now I didn't have any research license or cloud facility son Can you please send file after 7 days if possible. nOr send me that updated file then I will try to simulate any other place. nPlease explain logic behind opposite direction of angular velocity and remote displacement. I didn't understand that yet so please elaborate for better understandnAnd please send that simulated file if possiblenOnce again Thank you so much for always giving great feedback and helping us.Give Regards, nMihir Aminn
    • peteroznewman
      Subscriber
      nWhich direction do you understand the workpiece rotates, the blue arrow or the orange arrow?n
    • MAMIN219
      Subscriber
      In your above picture nArrow with blue colour which is direction of workpiece. Tool travel is -z direction according to coordinate system. nIf any wrong concept please highlight this and give your feedback with reason for better understand. n If you have cloud facility with you and possible then run this simulation so that i can understand properly temperatures effect in this simulation which main aim of my simulation.Otherwise send me your updated file for better understand which will take very less time consumption. So that i will try to simulate as soon as possible. n
    • peteroznewman
      Subscriber
      nYou intended to rotate the workpiece in the blue direction and that is what you did in your model.nAll the metal turning literature I have read shows cutting by rotation of the workpiece in the orange direction against the flat face with a small rake angle. I don't believe you have the correct understanding of metal turning practices.nI don't have access to a cloud facility to run this model, just a simple 4-core computer.nI'm not finished with my simulation yet, and I may not be happy with the result, so don't wait for anything from me, because I won't attach any archive I am not completely satisfied with. I can't change it after I attach it. I advise you to make your own mesh with a larger CL.n
    • MAMIN219
      Subscriber
      Thank you so much for your brief explanation and clarification of all doubt. nI will check CL and all things related to direction which you have guided me me and also I will change explicit material with failure criteria.With Regards, nMihir Aminn
    • peteroznewman
      Subscriber
      nI suppressed the tool and had only a cylindrical tube with an initial rotational velocity in rad/s, and a remote displacement scoped to the ID with an angular displacement in degrees. When I divide the angle by the end time, it is equal to the initial rotational velocity. I ran that simulation just to see the workpiece rotate at about 350 RPM.nI was disappointed to see the workpiece develop a huge strain over the simulation until elements were eroded away as they reached the 50% strain value I had set.nThis is an unexpected result.nI wonder if it has anything to do with the fact that the axis of the cylinder is a large distance from a global axis. I intend to edit the geometry and move the cylinder to be on a global axis and see if I get a different result.n
    • peteroznewman
      Subscriber
      Completed the test with the tube on a global axis, the elements were eroded by excessive shear strain. Something is very wrong with the model. I only expect a small amount of strain due to the centripetal forces, which are not very large because the diameter is small and the rotational velocity is small. I think a New Question is worth posting on this topic and I will do that soon.n
    • MAMIN219
      Subscriber
      yes sir sure. Thank you for always giving your valuable feedback and motivate us?n
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