Problem with setting of IMPVEL

Unknown
edited October 2020 in Community Q&A

Hello, I have some problem with setting of IMPVEL.

 

I need to procedure a repeated drop test analysis, so I created some floor.

for example, in the figure the blue floor is No.1 , and the red is No.2

In First step, I expect the ball drop to the blue floor and the red floor is move with the ball in a Zero relative velocity.

Therefor I created a Frame base on the ball, and set some IMPVEL load with the red floor and the Frame.

But actually the red floor is static.

Can anyone tell me what's wrong?

 

#attached is my input file and result.

 

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Answers

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited October 2020

    Hi,

     

    Is there a reason to add complexity with frames and imposed displacements?  The gravity load also on floor 2 and its rigid body nodes will result in a zero relative velocity with respect to the ball. 

     

    An example of imposed velocity through frame can be found:

    https://community.altair.com/community?id=community_question&sys_id=ff76483a1b2bd0908017dc61ec4bcbc6

     

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  • Unknown
    edited January 2020

    Hi @Simon Križnik thank your reply

    The attached file indeed make that floor in a zero relative velocity with respect to the ball.

    But actually I have added a card (INIV/Axis) in the engine file.

    If the card is added, the relative velocity condition seem to disappeared.

     

    All my setting includes Skew, Frame, gravity load , INIV, and IMPVEL is followed by the attached PDF file and input file.

    I want to reproduce the process for a repeated drop test analysis.

    One of steps is that control those inactivate floors to move with the phone.

    In detail, I need to give different initial velocity in several engine file, and make sure those inactivate floors is moved with my product.  

    I was trying to obey the guide but seem something is wrong.

     

     

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  • Simon Križnik
    Simon Križnik Altair Community Member
    edited February 2020

    Hi,

     

    there were some issues with frames and the solution is to recreate them from scratch.

     

    Note: In the method from the attached document, each floor has its own gravity acting sequentially (defined by a function). In your model there is only one gravity with respect to floor 1.

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