Search results

  1. S

    Mechanical device to lower a raised weight

    Try an escarpment mechanism like that of a clock or lighthouse motor maybe.
  2. S

    Need help designing a dumpling machine

    Neat, Are you a chef? What's the difference between a dumpling and a potsticker? I've not seen that type in the frozen food aisle but have seen the potstickers, almost the same just folded over like a taco and then crimped. Ditto on pantaz: a sphincter type machine (but don't put that on...
  3. S

    Design of a reinforced concrete beam

    Mashleyek, You might be better off going to someone in person for a bit of tutoring or a textbook. Short of that you might try narrowing your question(s) down to a principle or a more specific point that you are hung up on. S
  4. S

    Force required to pull a threaded tube from its socket

    If your thread length is at all generous your bolt will twist off or fail in tension before the threads shear off. You have two other checks, tension on the net area, and shear due to torque on the net area, one of these two typically governs. S
  5. S

    How To Check A Simple Structure Design?

    Abrogard, There are programs that will give you simple answers, vendor programs, try something like this, all this is from just one website: http://www.ilevel.com/services/ Forte™ Software Javelin® Software Comparis® Software TJ-Beam® Software Those are for wood I joists and...
  6. S

    Flight of rocks thrown through the air

    I've skipped a lot a rocks in my time. The point is to throw a rock (flatter the better) with spin along the surface of the lake or river and get it to bounce as many times as possible off the water. Over the years I've come across a lot of different rocks and have seen a lot of odd...
  7. S

    Vertical Wind Turbine Sail Boat Concept

    I don't beleive that 10-15 hp is enough for a 40 foot boat, but that's my opinion. There is software that can help you determine the power needed for various speeds. Might be worth a look for free software.
  8. S

    Vertical Wind Turbine Sail Boat Concept

    You probably want to do a couple of calculations to see a) how much power you can get from various sources b) how much power you need To move a 30 foot boat at reasonable speed you probably need around 20 hp to 40 hp maybe, that's around 1.5 to 3.0 kW. Can your turbine and solar panels...
  9. S

    How To Check A Simple Structure Design?

    Google: structural analysis software free download. You can get a trial copy and have at it. Many will even apply code prescibed loads. Use the help feature and examples to learn it. Looking forward to seeing the next Golden Gate (be sure to check the harmonics so it's not the next Tacoma...
  10. S

    Vertical Wind Turbine Sail Boat Concept

    Not well versed on electronics myself, maybe in the electrical engineering section you'd get some response. Wind turbines seem to be very popular right now, you may find everything you need on a vendors website, or compare a few. Speaking of against the grain, can you sail this hypothetical...
  11. S

    Vertical Wind Turbine Sail Boat Concept

    Interesting concept. You ask whether it is feasible, that depends on what your measure of feasibility is. Could it work and propel itself via wind and solar? I'd say yes. Would it be a profitable venture to design, build and sell? Doubtful. My guess is that a sail would work better for...
  12. S

    Pvc pipe compression strength

    That is interesting dr. I vaguely recall Captain Kangaroo too, hah. If ever I go to Texas I will try to remember the foam house. S
  13. S

    Need help with foundation design spreadsheet

    That helps. So for x number of bolts you want the lowest value of I/cA (inches). I think there is just two calculations to do for each, one with the axis through a bolt and one with the axis half way between two bolts. So set up spreadsheet to do both and then take the lowest value.
  14. S

    Need help with foundation design spreadsheet

    Ryan, can you make a sketch? That's easier than guessing.
  15. S

    2 screws orthogonal to each other -> compression

    Yes, the force vectors are parallel, colinear preferably. Which bones are you screwing together Seb? I know little about bones just what I gleen from gnawing on them (not human bones), and from pictures and TV. Seems they are often hollow, or at least the marrow is soft. My dog (incidently...
  16. S

    Why do we still need real world experiments?

    Babies and children learn from real world experience, they learn simple physics the hard way, falling, dropping, biting, etc. Can they learn it another way? It would be a different experience to be sure. Extrapolate?
  17. S

    Pvc pipe compression strength

    No pics? Any particular reason for a plastic and foam house? If it's really light uplift in high winds may be worth checking.
  18. S

    2 screws orthogonal to each other -> compression

    I concur with that phrak. Sebastian, you might google free body diagram too, there is also free software for simple animation but I've not used it. The sum of the pressure times the area of contact (not constant, increases closer to each screw) equals the sum of the force from the three...
  19. S

    Need help with foundation design spreadsheet

    I'm not a mcpainter but attached a rough sketch.
  20. S

    Need help with foundation design spreadsheet

    I think you'll find that the neutral axis will be parallel to a line drawn between two adjacent bolts.
  21. S

    2 screws orthogonal to each other -> compression

    What about them? There is friction (ouch).
  22. S

    2 screws orthogonal to each other -> compression

    I'm not sure either. The screws can apply compression if, when installed they, are put into tension, that should occur along the narrower, unthreaded part of the screw presumably nearest the screw head. The screw head has to seat such that the compressing force is applied at that point (where...
  23. S

    Need help with foundation design spreadsheet

    Maybe focus on one thing at a time. The bolt pattern is the easiest to solve. The lowest value for St will result using an axis perpendicular to a line bisecting the angle between two adjacent bolts. Odd number of bolts or not. (St=I/c tension side) 360 / (2 * number of bolts) = angle...
  24. S

    2 screws orthogonal to each other -> compression

    Sebastian, I don't really understand what you are doing, what is the purpose of the device, what do the screws do? Does it involve bones?
  25. S

    2 screws orthogonal to each other -> compression

    Google Poisson's ratio, that might help. How do you measure the compression? A load cell?
  26. S

    Resistor power rating

    Q, If you put too much current through your resistor it will get too hot. There are different resistor types intended for different degrees of power they need to dissipate. Maybe P=I^2 * R, so it's a current limiting rating.
  27. S

    Pvc pipe compression strength

    Dr, How about some photo's, it sounds like an interesting house. You can find an approximate number for it's buckling load using formula from Euler. Buckling force F = pi^2 * E * I / L^2 I=3 in^4 E=400000 lbs / in^2 L = 120 in You get 822 lbs, that's the buckling load. You'll...
  28. S

    Need help with foundation design spreadsheet

    Finding the bolt embedment is a project in itself, will just have to plow through it. You should be able to come up with factors for patterns with low numbers of bolts, it can be independent of bolt diameter and bolt circle radius. Plow through that. For larger numbers of bolts you can...
  29. S

    Moment of inertia (structural shapes)

    famine, you are picking up what I am laying down, yes between an L4x4x5/8 and an L4x4x3/4. That's unrestrained and in bending, again, do not know what your example is with the limited info provided. S
  30. S

    Moment of inertia (structural shapes)

    For stiffness comparing the moment of inertia is correct. Not sure what it's for but I agree with caleb, the torsional properties are quite different, and they are usually important. For example your steel angle will naturally twist when in bending and will eventually provide only it's lowest...
Top