What is the compatibility equation

  • I am not entirely sure of the compatibility conditions. looks like this for me.
    deltal1 + cos (alpha) deltal2 = 0

    could someone tell me if that makes sense or is wrong? thanks

  • Do you assume that delta_L (right bar) = delta-horizontal_L (left bar)?

    If so: I tried that at the beginning and the result was wrong for me ...
    But now I cannot say with absolute certainty whether the assumption is fundamentally wrong ... maybe I just made a mistake somewhere.

    The gods made heavy metal - and they saw that was good.
    They said to play it louder than Hell, we promised that we would!
    ~ Manowar ~

  • moment equilibrium was wrong with me ...
    ... just recorded true to scale and then discovered the stupid mistake

  • Moment equilibrium should look like this, shouldn't it?
    F * a + N2 * (sin (arctan (d / e)) * a) = N * c
    am I wrong there?
    if that is correct then it is definitely due to my compatibility equation

  • "F * a + N2 * (sin (arctan (d / e)) * a) = N * c"
    so for me it looks like this:
    F * a + N2 * (sin (arctan (d / e)) * b) = N * b
    but it could be because the names of the distances are a little different for everyone.
    However, all of them are the same length for me, except for the vertical part of the left bar

  • Did that work for you?
    what kind of compatibility condition do you have?
    ED: you're right ... copied it wrongly

  • I also have momentary equilibrium like this:

    F * a + N2 * (sin (arctan (d / e)) * b) = N * b

    Compatibility condition:

    delta_L (right bar) + delta-horizontal_L (left bar) = 0

    but can't get the right result ?!

  • looks like we have the same problem

  • I have the same with the compatibility. But also (probably) not true.

    I would like to know if anyone has a correct result at all.

  • Hello,

    if 1 is the right stick and 2 is the left, then the compatibility is:
    delta l2 = - delta l1 * d / sqrt (5 ^ 2 + e ^ 2)

    and the MomentsGGW around A:
    -S2 * d / sqrt (5 ^ 2 + e ^ 2) * b + S1 * b = F * a

    typed it in and it fits.

  • with d / sqrt (5^ 2 + e ^ 2) do you mean generally d / sqrt (d^ 2 + e ^ 2) or?

  • you only took the horizontal part for S2 at moment equilibrium (with my formula the same had to come out)
    in principle, your motto is the same

  • The equilibrium of moments is clear, but how do you come up with the compatibility condition?

  • Original from AndiBar

    if 1 is the right stick and 2 is the left, then the compatibility is:
    delta l2 = - delta l1 * d / sqrt (d ^ 2 + e ^ 2)

    Thanks!! If the right stick lengthened and the left shortened, I should already write "* d / sqrt (d ^ 2 + e ^ 2)" on the right side .. omg

  • Thanks !! Had the same mistake
    Ed: here also a program for the solution


  • How do you approach the compatibility condition?
    About a difference in height between the corner points, similar to the ZÜ? Or a twist?

  • The change in length from the right bar must be equal to the horizontal change from the left bar

  • ChristianL:
    but it has to be d / sqrt (d^ 2 + e ^ 2) instead of d / sqrt (e^ 2 + e ^ 2) called or?

  • Yes of course. Sry, I guess I got it wrong.

  • what a shit .... sin (arctan (d / e)) was on the wrong side the whole time too ....

    "I'll sign and polish bowling balls !! Show me a machine that can do this !!" - Arthur Spooner - KoQ