Undesired initial displacement?

Carlos Fondevila
Carlos Fondevila Altair Community Member
edited September 19 in Community Q&A

Hi colleges,

I'm working with a movement of a part, using the next Expression: `STEP5(TIME,0,0,0.1,80)+STEP5(TIME,0.2,80,0.3,0)`

And the part, at the start has a initial displacement of 80mm:

image

 

I don't understand where comes this initial displacement, any mistake in the Expression?

I attached the complet file.

Thanks!

 

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Best Answer

  • Ganesh Shanmugam
    Ganesh Shanmugam
    Altair Employee
    edited September 19 Answer ✓

    Hi Carlos,

    The second part of your expression STEP5(TIME,0.2,80,0.3,0) means at time 0.2 and less than 0,2 the step5 function will return 80. So use -80, STEP5(TIME,0.2,0,0.3,-80) to bring back the 80 of first step5 to zero.
    `STEP5(TIME,0,0,0.1,80)+STEP5(TIME,0.2,0,0.3,-80)`

    Regards,
    S. Ganesh

Answers

  • Ganesh Shanmugam
    Ganesh Shanmugam
    Altair Employee
    edited September 19 Answer ✓

    Hi Carlos,

    The second part of your expression STEP5(TIME,0.2,80,0.3,0) means at time 0.2 and less than 0,2 the step5 function will return 80. So use -80, STEP5(TIME,0.2,0,0.3,-80) to bring back the 80 of first step5 to zero.
    `STEP5(TIME,0,0,0.1,80)+STEP5(TIME,0.2,0,0.3,-80)`

    Regards,
    S. Ganesh

  • Carlos Fondevila
    Carlos Fondevila Altair Community Member
    edited September 19
    Ganesh Shanmugam said:

    Hi Carlos,

    The second part of your expression STEP5(TIME,0.2,80,0.3,0) means at time 0.2 and less than 0,2 the step5 function will return 80. So use -80, STEP5(TIME,0.2,0,0.3,-80) to bring back the 80 of first step5 to zero.
    `STEP5(TIME,0,0,0.1,80)+STEP5(TIME,0.2,0,0.3,-80)`

    Regards,
    S. Ganesh

    Hi Ganesh,

    You have reason, this Expression uses realtives movements, not absolute as I thought.

    Thanks!

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