9 votes

What is Saint Venant Principle?

The intuitive meaning of Saint Venant's principle is that "if two different sets of applied loads are statically equivalent, then the differences between the two stress patterns they create are only ...
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8 votes

What is Saint Venant Principle?

To add to @alephzero's answer, here's an layman's explanation of Saint-Venant's Principle: far enough away from the load's point of application, equivalent loads can be treated as identical. For ...
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6 votes
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What is this object?

Figure 1. Silicone steel stamped lamination, stator and rotor. Image source:HS Magnets Figure 2. On their way to becoming motors.
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  • 7,479
6 votes

Why/when do we use a transition fit?

A transition fit actually makes the end product more consistent than the clearance fit. In transition fit clearance (if occurring) is less compared to the clearance fit. Also, if interference occurs, ...
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  • 124
5 votes

Mechanical advantage of the 3-ring release system

I can't address all the questions you've posed, but at least one of the answers comes directly from the inventor, Bill Booth, as noted in the wiki. He holds the patent for the device (held?) and I had ...
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5 votes
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A latch that’s easy to open under lateral pressure

How about a levered latch like this (very rough sketch) showing the catching tooth above the self latching spring and the pivot point.
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5 votes
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Moments of Fixed-Fixed Beam

When trying to figure out whether or not a given reaction will exist at a given support, it's worth remembering what a reaction actually is. A reaction is the means by which the support resists the ...
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5 votes

Inverting motor polarities automatically to close and open a door

If I am not mistaken, you can use an H-Bridge for that. If you are using an arduino for example, there are a few motor drivers like L298N which do exactly that job (control the direction and speed of ...
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4 votes
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Scanning and modeling my personal vehicle for aerodynamic simulation

What you seek is called 3D photogrammetry and is a relatively exciting segment of 3D modeling. You can use those terms to search with your favorite search engine and be overwhelmed with options. I ...
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4 votes

Moments of Fixed-Fixed Beam

This is a statically indeterminate problem. I don't know what exactly you mean by moments develop at the fixed supports But I guess you mean if there exist any non-zero components of moment at the ...
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4 votes

Clutch role in a micro hydropower

The clutch provides an instant disconnect either for scheduled maintenance or in an emergency. If the water flow is stopped instantly, then the energy of that moving pipeful of water has to be ...
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4 votes
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What is a purpose of learning G-code?

Because some programs for some operations can be written quicker than the time it takes to produce the equivalent CAD file. Also use of variables makes the program more useful ie a program to ...
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4 votes
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Shape of the shaft of knurling device

Yes, it would be easier to drill the hole but there are other reasons. It's makes the shaft the same width as the red bearing also clamped by the green sides. The shaft will experience torque when ...
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4 votes

What is this mechanical pump called?

Figure 1. A scroll compressor. Image credit: Cacycle.
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4 votes

How can a mechanical pocket watch wind itself from movement, and does it really get damaged if wound "too much"?

I expect it works the same as a wrist watch type ; There is a weighted wheel , that is one side is substantially heavier than the other side . When the watch is moved , the heavy side of the wheel ...
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3 votes
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convection query

You have the right general approach, and the numbers look reasonable. Your airspeed isn't very fast, so I'm not surprised that the convection coefficient you calculate is less than 10 W m-2 K-1. Note,...
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3 votes

Why are there rivets on the drum case of a band brake

The circled portions of the image provided are not rivets. They are locking adjustment screws. According to information provided in an answer (number 2) on the bicycles stack exchange, the primary ...
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  • 6,022
3 votes

Vehicle Train Towing

In your example the pickup trucks are not load bearing because the weight of the trailer is resting on the trailer wheels. As such the drive wheels of the pickup trucks are likely to skid. The goose ...
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3 votes

Which frame is optimal for children's bicycle trailers? tubular or rectangular frame and why?

I assume that you are talking about a steel frame with a wooden body mounted on it. In general round tube is more efficient, but if the loading is primarily bending in one direction rectangular ...
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3 votes

Explain tolerances in technical drawing

It says the flats shall be within 0.100 units of radial dimension positioned with reference to 'A'. i.e. if you were to make the rim which is a perfect circle, then mill the flats at the three ...
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3 votes

Explain tolerances in technical drawing

I believe this is a related mating envelope related to datum A for the three plates, per ASME Y14.5-2009.
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3 votes

How to derive deformation gradient or displacement gradient?

From a theoretical standpoint, the displacement gradient is equivalent to strain (assuming a structural problem). Numerically, you can obtain the derivate of a quantity through multiplication with ...
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3 votes

Force limits for gear rack and pinion gear

The life time of gears (which a rack and pinion mechanism basically is) is limited by teeth failure, wear, and pitting. So the answer to your question not only depends on the force acting on the rack, ...
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3 votes
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4 Gears in a Circular Pattern - Calculating the Proper Distances for Meshing

Let’s consider gears as being represented by a pitch circle on which lie several equally spaced dots with a number equal to the number of teeth. These dots can either represent the teeth or the gaps ...
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3 votes

What is the name and purpose of this Instrumentation / Mechanical fitting

I'd call the blue part the transmitter housing. This usually contains electronics for sensor signal conversion, which converts the sensor (or probe) low level ...
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  • 51
3 votes

When calculating a force, why do I get different result when I try to calculate via torque vs via sum of forces at an axis?

Essentially, the problem is poorly conditioned. As drawn, it cannot be in static equilibrium, which is why the equations of equilibrium are returning inconsistent solutions. We can confirm this by ...
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3 votes

Regarding design of a compressed air delivery system based on a screw air compressor

That is on the high pressure end of normal pneumatic conveying blowers, but they are out there. See the notice at the bottom of the attached chart. http://www.hsiblowers.com/products/high-speed-turbo-...
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  • 3,371
3 votes

Bending moment when there are no constraints

The impulse causes lateral acceleration of the rod and rotation of the rod. $$ P=m\frac{dv}{dt} \quad \text{for lateral acceleration}$$ $$ P=I\frac{d\omega}{dt} \quad \text{for rotational acceleration}...
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3 votes
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What is this mechanical pump called?

If the screws look like a pair of thick and long interlocking archimedes screws, then the device is called a rotary screw compressor. You can think of it as a special case of a roots blower, where the ...
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3 votes

How can a mechanical pocket watch wind itself from movement, and does it really get damaged if wound "too much"?

First of all, this is very much depended upon the implementation. Having said that, the chances that damage occurs during self winding are minimal. It would take a pretty bad design to do that, and ...
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