Recent content by JBA

  1. J

    Torsion Spring Reaction Force

    We need to see a side view of the assembly to understand how and where the two walls are supported along their lengths.
  2. J

    Basic Compression Spring Theory

    @hutchphd Thanks for that. I was only dealing with the required hole depth and failed to look at the solid height of the spring. Edit: So bottom line, he can't use the new spring.
  3. J

    Basic Compression Spring Theory

    @helpinghand : Ignoring all posts after @hutchphd post #8, if the two compressed lengths hutchpad gives in his post are correct and your original hole depth is 15 mm then: the difference in the installed height is: 22.75 mm - 17.3 mm = 5.45 mm and the hole depth for the new spring = 15 mm -...
  4. J

    Basic Compression Spring Theory

    If the compression and force for the the new spring are the same as the old one then the pocket depth does not change.
  5. J

    Basic Compression Spring Theory

    Take the required compressed height of the new spring for the same load as the current spring and subtract the desired exposed height and the result is the required depth of the hole for the new spring.
  6. J

    Is this still an equivalent force?

    For a drop test, the basic formula is PE = mgh (where PE changes linearly with h) and assuming you lift the weight to the same height for every test then the h will automatically be shorter and the resulting KE will be less for the shorter rope by the ratio of the two rope lengths.
  7. J

    Easy tool to see a cross section?

    You need to be more specific and give a sketch of the tube and the direction of flow relative the tube and angled end cut orientation
  8. J

    PF Photo Contest - Panorama (12/29-1/3)

    Inca Ceremonial Sacred Valley above Cusco, Peru which is (barely) seen in the far distance in the left end of the photo
  9. J

    Understanding the Value of the Second Moment Of Area

    I apologize, I misunderstood the issue of your confusion. Your diagram and equation results are fully correct for the two cases. The Ix' for the y = h case is a derivative of the central axis Ix case done by applying the "parallel axis theorem": Ix' = Ix+Ad^2, where d is distance of Ix' from...
  10. J

    Understanding the Value of the Second Moment Of Area

    You are using the wrong formula. The one you used is for the case where y=d. The correct formula for a neutral axis at y = 1/2 d, as shown in your figure, is: bd^3/12 = 85.75.
  11. J

    PF Photo Contest - I Want To Go Back! (12/21-12/27)

    This one is really tough to choose while taking into consideration both great photo technique and amazing scenes combined.
  12. J

    Calculating the spring displacement response from an acceleration input

    To start you need to determine actual dynamic displacement of your mass vs the static load displacement amplitude Xdyn/Xstatic ; and. for that you must first determine the β ratio between the natural frequency of your spring and the input frequency of your shock profile. The equation for the...
  13. J

    Fluid flow resistance

    How much inlet pressure does it need to resist? PS The Tesla valve has a very high backflow to forward flow resistance but does not fully stop backflow.
  14. J

    Electrical Load center terminal screws - where to buy?

    As stated above, terminal strips come with their appropriate screws so your best bet would be to simply buy a terminal strip with the number of screws you require. As per the below...
  15. J

    Bistable spring mechanism with a different transition point?

    You can show the positions of each element of the assembly in a sequence of diagrams without using animation. The the current figure is to ambiguous to be of help.
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