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Mechanical Engineering


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DrD last won the day on March 16

DrD had the most liked content!

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  • Gender
  • Location
    Iowa, USA
  • Interests
    Kinematics, dynamics, mechanics of materials, Theory of Machines, machine design, vibrations
  • Present Company
    Machinery Dynamics Research
  • Highest Qualification
  • Engineering Qualification
    Registered Professional Engineer, TX, WI (Ret'd)

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  • Achievement /recognition/ Certifications
    Consulting work for a variety of industries, particularly in the IC engine related area (Torsional vibration analysis, shaking force analysis, engine cam design, system simulation).

    Author of several books, including one widely used textbook for Theory of Machines.

    Life Member ASME
    Member SAE
    Member SNAME

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  1. Dear Dudley, It would be a real reach for me to "love CFD," but I will agree that those are rather nice simulations. DrD
  2. Dear John, Well, it is really all pretty simple, but only if you know what you are doing. As you evidently believe this is true, it is clear that you do not know. Or, perhaps you do know, and simply wish to scam folks. Either way, keep working on your miraculous inventions and leave real engineering to those who do know what they are about. DrD (Yes, I really do have a PhD in mechanics.)
  3. While this looks like a fairly simply problem on the surface, it has the potential to be quite complex. The fact that the shaft is vertical complicates the situation because it does not offer the stabilizing force of gravity. What you are asking for is professional work, well beyond the scope of the Q&A here at the ME Forum. You should contact a competent Professional Engineer for this assistance. You can send me a PM if you want further help. DrD
  4. You are welcome to disagree, but I will stick by my statement. Numbers may influence emotions, but ultimately it is emotions that drive decisions. DrD
  5. It does not look to me like the red screw will significant change the belt tension which is the source of the brake torque. How do you envision applying/releasing this "brake"? DrD
  6. Unless you are a fully funded research organization, forget the idea of building a rail gun. It is exceedingly dangerous and expensive. That said, why would you want to use such an expensive material for the rails? Are you aware that electrical erosion is a major problem in the rails of a rail gun. A typical rail gun some years back (about 2006) needed new rails about every other shot. Also, while we are at it, what will you use for power? It takes a vast amount of current to drive a rail gun. Force varies with the square of current, but the multiplier is quite low. In the early 2000s, when I was working in this area, we were looking at around 6 mega-amps peak to get a exit velocity of 6 km/s, as I recall. If you can't do better than that, you will be way behind the times. DrD
  7. OK, got it. Now, you need to draw a free body diagram (FBD) for each mass. Show only real forces acting on the masses, no mass x acceleration terms. Do you understand that the force through a dash pot if proportional to the relative velocity of the end points? Once you have the FBDs, you should be able to write the sum of forces on each mass. DrD
  8. This is a strange situation. Why did you stick around to finish an ME degree if none if it interested you? Does that reason, whatever it may be, give you a hint as to what you should do with your life? DrD
  9. You have not given us a system diagram, so we have no way to know how the springs/dampers are connected to the masses (which masses connected to which spring or damper). This is essential information. Please provide it, and we may be able to help you. DrD
  10. Take a look at Post #25 (Feb,, 2016) on the Mechanics Corner blog at this site. You will find a somewhat similar problem worked in some detail. If that is insufficient, send me a message. DrD
  11. Sure, it is certainly possible to find many things regarding this mechanism. But what are b and d? Is it intended that the spring element is perpendicular to the lever? If not, then a better figure would show that it is clearly not perpendicular. This is important. DrD
  12. DrD


    There is a retired SR-71 on display at Eglin AFB, Florida. I was able to walk right up to it and touch the wings; it was pretty scary, even when sitting entirely still. Those of us that never flew still have some appreciation for the astounding engineering that went into these planes. Thanks for your comment, Dudley. DrD
  13. I think you are a bit confused one one of your engineering types. Specifically, I question whether it is appropriate to speak of a "financial engineer." I think that is nonsense. Finance is based on emotions and psychology at least as much as it is on hard science. I also have to ask, why did you make this video? What is the point? I must be missing something. I really did not learn much (other than about the "financial engineer"!) DrD
  14. Dudley, you wrote your "rant" back before the recent catastrophe in Texas and the rest of the south central USA. That even just reinforces what you said about the inadequacy of wind power. It is all "feel good" and not engineering at all. The same can be said of solar. We messed up (IMHO) back in the late '70s (or was it '80s?) when we walked away from nuclear power. By now, it is quite likely we would have solved the waste disposal problem, if we had continued to pursue it. As things stand, we are still on square one. This was a good post. Thanks, Dudley. DrD
  15. And this addresses the question how? DrD
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