Mechanical Engineering

# DrD

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DrD had the most liked content!

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## Profile Information

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

• 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
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1. ## Mine Hoist Problem, Hint #2

Mechanics Corner A Journal of Mechanics & Mathematics by Dr.D, #54 B Mine Hoist Problem, Hint #2 Introduction The original Mine Hoist Problem was posted 25 August 2020, and the first Hint was given on 8 September. We are now almost one month into this problem, and thus far no one has sent me even so much as a question other than Tim Dennison's request for a video. I'm not quite sure how to understand this. I see two basic possibilities: 1.The problem is so dull and uninteresting that no one could possibly
2. ## Rack and pinion lift

Sounds like you are narrowing your question to friction losses in the rack and pinion only, exclusive of the guide mechanism. This depends upon the details of the tooth design (arc of approach/arc of recess) and upon the lubrication. If done well, these will probably be small relative to the friction in the guides. DrD
3. ## Rack and pinion lift

Friction will be a major problem, and it all depends upon how you guide the moving member. What do you plan to use as a guide? There is simple sliding contact, various ball or roller guides, etc. A lot depends upon your budget, but the better the guide quality, the easier your system will work. DrD
4. ## Hint for Mine Hoist Problem, #54

It appears that only a very few folks are even attempting these problems, but it also appears that no one has sent me a solution. For that reason, a small hint seems to be in order. Hint: Turn the picture upside down. For most of us, it is conceptually easier to think about the problem if the X-axis goes to the right and the Y-axis is upward. Of course, if you do this, you must recall that gravity then acts up, not down. Don't be shy; give it a try!!
5. ## Defense products

Was there supposed to be a question or a comment hidden in there? DrD
6. ## motor model

You question is not very specific, and after three tries, no one has answered you. Please be more specific. DrD
7. ## College paper

Do some internet searches on impact absorption, collision absorption, energy dissipation in metal foams. DrD
8. ## Mine Hoist Problem, #54

And just how would I do that, Timothy? 1)Do you want a video of the system (which only exists on paper at this time) and is therefore impossible to do? or 2) Do you want a video of me talking about the problem? What would be the point of that? the written words "hold still" and can be read and re-read as many times as necessary. What do you have in mind, Timothy? DrD
9. ## Mine Hoist Problem, #54

Well, here we are on 31 August with 151 views (presumable this first page only), and only 4 downloads (necessary to really see what the problem is). That is just slightly more than 2.5% of people bothering to actually look at the problem. How could this group be more lacking in curiosity? DrD
10. ## Mine Hoist Problem, #54

Mechanics Corner A Journal of Applied Mechanics and Mathematics by DrD, # 54 © 25 August, 2020 Mine Hoist Problem Introduction As we saw in the previous problem (A Hoisting Problem for Engineers, #53), hoisting problems can be fun. This has gotten me to thinking about some other hoist related problems, and here I present three variations on a new problem. The problem is much the same in all three cases, with only small changes in the geometry. These changes do appear to significantly modify the system resp
11. ## How can we make this website one of the best knowledge network for mechanical engineers

James , You have identified in your own statement why no one is interested. You said, "one way is to do my project to make speed and torque increase that will violate a law of engineering and open many new doors for millions for all of history." No doubt many folks would like to open new doors and make history, but when you talk about violating the laws of engineering (physics), you are asking for the impossible. The laws of physics are not man-made laws that can easily be replaced with other man-made laws. Rather the laws of physics are the distillation of observed truth in the natu

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13. ## Binomial and Taylor expansion of differential Equations

Dear Bruce, As you well know, that's how things go at times. Better luck next time! DrD
14. ## Can I help anyone to publish a paper or research?

Perhaps you might start on a research problem, and when you think you have something publishable, look for a "sponsor" to co-author with you? This "sponsor" might be a faculty member or a working engineer, but someone who already has some publications and knows the process. As I read your original request, you are asking another person to identify a promising research problem and then let you do a part of the work to get your name on the paper. The big problem with that, as I see it, is the very limited value of your contribution. Suppose for example that I propose a problem that I'm
15. ## Can I help anyone to publish a paper or research?

You say that you are a ME student working on a bachelor's degree. If you are already in college, why are you seeking a scholarship? Are you trying to change universities? DrD
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