Drop_Test of ball

hari0811
hari0811 Altair Community Member
edited November 2020 in Community Q&A

I am trying to perform a simple drop test of ball on ground. (Both being Flexible and of same material (Steel)).
The initial gap between ball and ground is 5mm. but when i see the animation file, the ball bounces after ~4.72mm.
can some one please help me.

 

Unable to find an attachment - read this blog

Tagged:

Answers

  • hari0811
    hari0811 Altair Community Member
    edited November 2020
  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Change the material type to M2_PLAS JOHNS ZERIL (elasto plastic material) and run the analysis. Provide appropriate material properties so that a realistic behavior of the simulation can be achieved. 

  • hari0811
    hari0811 Altair Community Member
    edited June 2016

    ok I will launch using elasto plastic material and update you.
    But i am wondering how will that effect the physics of my problem. The ball should touch the other part and it should bounce back.
     

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Material properties plays a vital role in simulation.

    The input parameters will define the weight of the component. So input a reasonable value of E and rho.

    Please update after the run.

     

     

    <?xml version="1.0" encoding="UTF-8"?>cont.PNG

  • hari0811
    hari0811 Altair Community Member
    edited June 2016

    Hello George

    I have tried using  M2_PLAS JOHNS ZERIL  and i have same problem.
    can you send me the your model from the picture

    Thankyou

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Can you upload the model now

  • hari0811
    hari0811 Altair Community Member
    edited November 2020
  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Model the ground with elasto plastic material and run the analysis. Update it with the Plas Johns Zeril material.

    .

  • hari0811
    hari0811 Altair Community Member
    edited June 2016

    Hi George

    I have solved the problem, The problem was in GAPmin which was taking a default value because of which it was not coming into contact.

    Now i have a new problem which is drop in energy when the ball contacts with ground. ( My ground and Ball are flexible)

    Do you know why such thing happens ?

     

     

    <?xml version="1.0" encoding="UTF-8"?>Energy.png

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Please upload the deck file (0000.rad) and T01 file.

  • hari0811
    hari0811 Altair Community Member
    edited November 2020
  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited July 2016

    Hi Hari,

     

    Can you check if there is any change in the KE

    Usually if the collision is a plastic collision there will be considerable KE loss due to plastic deformation.

     

    Also, total energy doesn't account for hourglass energy. So you may also have to check hour glass and contact energies.

  • hari0811
    hari0811 Altair Community Member
    edited July 2016

    Hello Prakash

     

    I am using Elastic model hence plastic deformation is not the problem,
    I just checked the contact energy, it has some energy which is the drop in energy.

    Total Energy = sum of internal energy +  kinetic energy + external force work - Contact energy - hourglass energy - internal spring energy ?
     

    Is my understanding is correct ?

    <?xml version="1.0" encoding="UTF-8"?>KE.png