Huge vibrations at impact analysis

User1357
User1357 Altair Community Member
edited August 12 in Community Q&A

Hello,

i simulate an impact analysis on a wheel carrier. The bumper is supposed to move in y-direction against the wheel of the carrier. The carrier ist locked at the back except for rotation along x-axis. 

The Problem: The wheel, and also the whole carrier are oscillating/vibrating extremly, although the material is steel and the parts are thick.

I would expect that the whole carrier is rotating along x-axis and the gravity slows it down. Normally the bumper is supposed to move with a speed of 25 km/h and just bump the wheel for a very short moment.

I already reduced the velocity of the bumper too have less inertia, but it didnt help alot.

 

Can somebody help me with that? I attach the .rad-file and the hm-file.

 

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Answers

  • User1357
    User1357 Altair Community Member
    edited August 6

    I changed the settings: There is an imposed displacement on the wheel (where normally the bumper would cause the impact) with 10mm within 10 miliseconds. After the 10 miliseconds gravity is activated with 9810 mm/s^2 for the remaining 90 miliseconds. So i have in total 0.1 seconds run time. 

    But why is the model shaking like that. I would expect, that after the 10 mm of displacement the whole carrier starts to move down again, since gravity is activated. I created a spring between the two holes with only free rotation along x-axis. Every component is deforming extremly, which problem could that be?

    I attached a video of the animation and the .rad file, i hope somebody can help me here.

     

     

  • AdrienR
    AdrienR
    Altair Employee
    edited August 8

    Hi,

    The results you obtained seem reasonable to me. Your materials are fully elastic, so the structure is vibrating after the release of the imposed displacement.

    The imposed displacement also created a global upward motion of the structure, and gravity will take time to bring it back to the ground.

    Thanks.

  • User1357
    User1357 Altair Community Member
    edited August 12
    Adrien Robert_22249 said:

    Hi,

    The results you obtained seem reasonable to me. Your materials are fully elastic, so the structure is vibrating after the release of the imposed displacement.

    The imposed displacement also created a global upward motion of the structure, and gravity will take time to bring it back to the ground.

    Thanks.

    Thanks for your answer. 

    I also used M2 Elastoplastic material, but the shaft is still deforming extremly and the wheel is moving quickly upwards and downwards.

    But why is the shaft where the rim is connect deforming that much? All the Materials are steel. Since the rotation along x-axis is free i expect that the whole carrier rotates/moves along x axis. 

    What can i do to stop having such vibrations and big deformations?

    image

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