Hyperelastic Material Not Deforming Much

hariprakashhariprakash Member Posts: 2
edited October 2020 in Materials


Hi everyone,

I am currently trying to model a single flexible robot arm. The arm deforms as pressure is being applied but even if more pressure is applied, the bending is the same. Below attach are my settings as well as my geometry as well as the end product I want to achieve.

P/S: I am using ANSYS Academic Student 2020 R2

I have been trying for a week and still couldnt get the result. I would be really grateful if you could help me out.


Thank you in advance


Sorry for the wrong end product. Below is the end result I want to achieve.


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Answers

  • peteroznewmanpeteroznewman Posts: 11,546Member

    @hariprakash

    You included a zip file with the image of the Final Result.

    But you have a structure that doesn't have these side pockets that create the structure.

    How do you expect to get the final result when the geometry doesn't have the features needed to create the final result?

  • hariprakashhariprakash Posts: 18Member

    I am sorry for including the wrong image. The post is updated with a new photo. What am trying to achieve is to bend my arm the way the image is shown. For now its bending but even if I increase the pressure, its not bending more

  • peteroznewmanpeteroznewman Posts: 11,546Member
    edited October 2020

    @hariprakash You can't update the post with a new photo. In this new Forum, you can only edit for 1 hour, then the post is frozen. Attach the new photos in a new comment below.

  • hariprakashhariprakash Posts: 18Member

    here is the photo as requested. The problem i'm facing is that is bending the directing im applying pressure to. But the angle of curvature remains the same even more pressure is applied.

  • peteroznewmanpeteroznewman Posts: 11,546Member

    @hariprakash

    The cross-section geometry doesn't look like the photo. Next time you take a photo, try using a dark background. White on white is not easy to see.

  • hariprakashhariprakash Posts: 18Member

    @peteroznewman

    I am sorry for the late reply Peter. I redid my simulation and almost got my answer but I would like to know if I can bridge pressure and joint rotation together. Below are the settings ive made. Properties i am using are

    • Density - 1190kg/m^3
    • Hyperelastic - Yeoh model

    a. Contacts

    b. Joints

    c. Pressure

    d. Joint rotation

    e. Analysis settings

    f. Result 1

    g. Result 2


    As you can see there are 3 chambers within the main chamber. My goal is to inflate one of the internal chamber with pressure and where size of inflation should be proportional to the amount of pressure fed and the arm should bend accordingly. As you can see from Result 1, there is bending but no inflation but when I suppress Joint in analysis settings, I get my inflation as in Result 2. How do i combine both where the bending is affected by the pressure applied in of the internal chambers.


    Thank you in advance @peteroznewman.

  • hariprakashhariprakash Posts: 18Member

    Thank you Peter. I understand now. Guess ill check the real model and then try out.

  • hariprakashhariprakash Posts: 18Member

    Hi Peter @peteroznewman ,

    Hope you are doing well. I am doing another new geometry using hyper elastic material. Single chamber, 2 chambers and 3 chambers. The bending of the 1 and 2 chambers are what i expected but for the 3 chambers, the model isnt solving. I just added extra one chamber for the 2 chamber model. The settings are the same just but still i couldnt get ANSYS to solve. As you can see, the bending isnt what im getting from 3 chambers. After all, i just added one more chamber from the 2 chamber model

    1 chamber

    2 chambers


    3 chambers



    Thank you in advance Peter.

  • hariprakashhariprakash Posts: 18Member

    hi @peteroznewman

    Hope you are doing well. i tried again but still fail to solve in ANSYS.

    Below are the images.

    The difference between the two images are that the first one has no pressure in the last chamber (Chamber 3) and the second image has pressure in the last chamber (chamber 3). When there is no pressure, ANSYS able to solve it but when i include pressure in the 3rd chamber, ANSYS couldn't solve it. The error displayed was.

    "The solver engine was unable to converge on a solution for the nonlinear problem as constrained"

    The ANSYS i am using is ANSYS 2020R2 student version.


    Thank you in advance @peteroznewman .I really appreciate your help


    Hari Prakash Thanabalan

  • hariprakashhariprakash Posts: 18Member

    hi @peteroznewman

    is it possible to get the bending angle in ansys for my structure?


    Thank you in advance

  • hariprakashhariprakash Posts: 18Member

    @peteroznewman

    Hi Peter. Hope you are fine. I am having a slight problem with my data.

    Im just wondering, why is the position of my node in either X, Y or Z axis is extremely small. it starts with like e-06 m. How do i start my point from 0 and then displays the coordinates from there.


    Thank you Peter

  • hariprakashhariprakash Posts: 18Member

    hi @peteroznewman

    Hope you're doing ok. Just want to ask you. What is the min, max and average column in total deformation? where can detailed information about it?


    Thank you in advance

  • hariprakashhariprakash Posts: 18Member

    hi @peteroznewman

    Hope you are alright. Just wanna ask. How do i specify a node on a specific location? For example, my cylinder height is .065m. Now i wanna specify a node at the top of the cylinder at (0, .065, 0). That way, i can get the mid point at the end effector of my robot.


    Thank you in advance peter.

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