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Mechanical Engineering


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DrD last won the day on February 15

DrD had the most liked content!

About DrD

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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. 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
  2. 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
  3. And this addresses the question how? DrD
  4. DrD

    Mine Hoist Problem, #54

    Dear Mark, After thinking further about your response, I finally decided that I should tell you more about the situation. The load to be lifted out of the shaft is a massive blob of pure gold, studded with 50 carat diamonds. Your team has been searching for it for months, and now it has been found. Now, do you use the primitive lift described in the problem, or do you place an order for the modern equipment you recommended? Oh, I should also add a couple of other factors that may influence your choice. The action all occurs at a very high altitude (22,000 ft above sea level
  5. It is far better for you to read the book. I have not done such problems since I taught a course where they were included in the Fall semester, 1969. My memory is a bit fuzzy, and I'd probably mislead you. DrD
  6. DrD

    Mine Hoist Problem, #54

    Thanks for your comments, Mark. If we complicated the problem as you recommend, it would be fa beyond the likelihood of anyone working it. As it is, I am unaware of anyone having work the problem. One of the big points that you evidently missed is the kinematic aspect. I am well aware that slopes that follow exactly parabolic form are exceedingly rare. It was never intended to represent any actual mine, but rather a hypothetical situation intended as an exercise for folks to develop their skills. DrD
  7. Dear Dudley, I'm quite familiar with the soap bubble problem, but there the quantity minimized is the surface energy which is proportional to surface area. I fail to see the connection to the cooling tower problem. Would you elaborate, please? DrD
  8. There is lots of discussion of problems of this sort in Den Hartog's Advance Strength book. DrD
  9. Dudley, I'm still very much here. I'm in the maximum risk group for WuFlu since I'm 80+, but I'm firmly convinced it is just a political fantasy. I never get flu shots, and I don't expect to get the WuFlu either. I have not had a land line for some years now. If you need to reach me for some reason, send me a message through the ME Forum message system. Were you reading TMR? I had no idea anyone was, so I abandoned it after some medical issues slowed me down pretty badly. DrD
  10. If the hands-on stuff is what you are good at and enjoy, why bother with engineering? Become a mechanic (a machine repairman). Engineering is about design, much more than about hands-on operations. It is certainly true that some engineers work more directly with machines in such roles as planning and supervising repairs, but there again, it is more of a guiding role than a hands-on role. DrD
  11. Your hand written work is much too difficult to read. Can you put this into a computer written format, please? DrD
  12. I have never seen such a machine, but it does not look too difficult. Would you not be able to accomplish this with a simple hinge? Imagine a tube running front to back on the machine. It is secured unable to rotate on the rear unit, but allowed to rotate in bearing through some angle on the front unit. Wouldn't this do the e job? I think so. As to fatigue life, that depends upon the specific design details, specifically the loadings and resulting stresses.
  13. It is conceivable, but if will likely be horribly expensive due to the special materials required. Why would you want to do so? Can the cost be justified?
  14. To really get any help, you are going to have to be more specific. In particular, 1) Looks like you are showing your 50 lb load as being on wheels. What sort of wheels and how much rolling resistance is there? 2) Why do you show the connecting cable as inclined? Is this an essential feature? 3) Do you want o both pull the load towards the motor and then push it away, or is it one direction only? How far does the load need to move? I strongly suggest you tell us more about the purpose for th is device. That will clear up a lot of issues. DrD
  15. I suggest that you start with some FBDs for the movable elements. You will also need a constraint equation expressing the constant length of the belt. It is an interesting problem. Good Luck! DrD
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