8
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Can epoxy bond two Aluminum alloy beams?
It does nothing for aerodynamics, the cavity makes the thing bigger and hence producing more drag (a very hypothetical reduction of Cd cannot change that). The point is simply the weight.
Perhaps it ...
7
votes
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How to add friction to a rope without using abrasion
You need to separate the braking from the winding / unwinding. Have a look at a ship's capstan. You want a miniature version with very high friction between it and your rope so there is no sliding and ...
- 11.1k
7
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How friction between stator and rotor is dealt with in an electric engine/motor
... there's no space between the rotor and the stator.
There is always an air gap between the rotor and stator.
Iron has a permeability of about 1000 times that of air so the trick for maximum ...
- 11.1k
6
votes
Does a washer really increase static friction force?
No it doesn't, and it isn't meant for that either. A standard flat washer, that is. It's meant to give the nuts and bolts a better support, and it protects the material against the nut which may ...
- 1,204
6
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Refute my assumption: Bearings Don't Improve Efficiency
Your initial assumption is a bit flawed. You can not just draw the conclusion that all friction is the same. It is like saying all birds i know of can fly thus all birds can fly. Which is obviously ...
- 3,684
6
votes
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Why is the friction factor in laminar flow independent of pipe roughness?
In laminar flow, you assume a fuild layer near the pipe wall with flow velocity = 0, and progressivly faster flowing layers towards the middle of the pipe. That's why it's called laminar. Because ...
- 4,791
5
votes
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Ideal funnel design for powders
The problem you have is more complicated than you think. Any industry that deals with the storage and movement of granulated/powdered materials has to deal with this and most have unique solutions.
...
- 9,752
5
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What is the exact concept of bearings?
If that is true, then would not be better off just to remove the whole setup and have the axis of rotation free from bearings ...
Ball bearings change a system from sliding friction (as in a journal ...
- 11.1k
5
votes
Wheelbarrow minimize wear
Assuming the same material and tolerance, I pick the right-hand detail.
Due to having a larger resistance arm against shimmying and lateral shock when the wheel falls into an unsymmetrical pot-hole ...
- 22.8k
4
votes
How to find required clamping force of bolts to prevent flange faces from twising due to torque?
The simplest way by far is to select a prospective bolt, calculate the clamping force this creates when it is torqued to rated torque, and use the bolt circle as an approximation of the moment arm. ...
- 5,105
4
votes
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Need help regarding working of drum brakes
... then how is it stopping the vehicle's car, that is bringing it instantly to rest.
It's probably an error in your writing but brakes don't bring a vehicle instantly to rest. They decelerate the ...
- 11.1k
4
votes
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Disc Brakes - Swept Area , why is larger better?
Brakes primarily convert kinetic energy to heat energy. So a large area can absorb more heat lowering the peak temperatures ;of course this is strongly affected by the thickness/mass of the discs and ...
- 6,182
4
votes
How to add friction to a rope without using abrasion
I've loaded a winch with Spectra line, not quite as abrasive as Kevlar, but similar in strength and size. The key factor in such problems is to load the spool while the line is under tension. I used a ...
- 7,307
4
votes
Derivation of static & kinetic friction formula
Coulomb friction is an empirical law. It was observed that the force required to move an object was proportional to its weight.
Regarding static and kinetic friction it is possible to use graphs like ...
- 24.3k
3
votes
Refute my assumption: Bearings Don't Improve Efficiency
Bearing have rolling elements specifically designed to insulate the two moving surfaces from coming into contact with each other and let the move freely (almost).
There are many types of bearings, ...
- 22.8k
3
votes
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Applications with combination of high friction and low wear?
As mentioned in the comments you don't actually want high friction between gear teeth, the tooth profiles are designed to roll over each other indeed the ideal is to minimise any sliding friction ...
- 15.3k
3
votes
Is there any material that has a higher kinetic friction than static friction?
The numbers for static and kinetic friction in aluminum-on-aluminum interactions, cited by @albseb back in 2016, are unreliable. Strangely though, they're the only published values.
I'm a physics ...
- 31
3
votes
Why is the friction factor in laminar flow independent of pipe roughness?
The explanation is due to the fundamental physics of momentum transfer. In all cases of continuum flow, including laminar, transition, and turbulent flow, the zero (no-slip) boundary condition ...
- 417
3
votes
Calculating Bending Force on a Fixed Metal Plate
In my view, you are attacking this from the wrong angle. The pipe will expand by about 150 mm. You need to give your pipe run the required space to do so.
Look if you can use existing bends (this is ...
- 4,791
3
votes
A quantity to measure whether brakes should be repaired
Indicators to warn that brakes need repair do exist.
They are on many cars, but not all and are called pad wear indicators.
These are small (usually copper or brass) metal studs held in an insulator ...
- 16k
3
votes
Accepted
Find minimum horizontal force required to keep the block and wedge stationary?
What you are learning here is the effect of the "inertia force" due to motion.
In order for both blocks to move together, we can simply write the equation, $F = (M + m)*a$, by the law of ...
- 8,232
3
votes
Accepted
Inconsistant load cell readings - (static) fiction perhaps?
When you are raising the plate you are also raising the bearings and since they need to roll there is the frictional component pulling down on the bearings and pulling down on the plate.
When you ...
- 496
3
votes
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Equivalent viscous damper for friction damping
In general this is impossible, because for a given value of $F_e$, the friction damper dissipates a fixed amount of energy per cycle of vibration independent of the vibration frequency.
This is (...
- 12.6k
3
votes
Is there a positive displacement pump that experiences only rolling resistance?
Rolling diphragms have been around for many years now. See...
https://www.diacom.com/rolling-diaphragm-theory
With or without the spring.
(With enough vacuum in the top you can get the membrane to ...
- 496
3
votes
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Examples of Materials with a Coefficient of Kinetic Friction Very Close to or Equal to Coefficient of Static Friction?
Steel/Teflon - $\mu_s = \mu_k = 0.27$
Glass/Teflon - $\mu_s = \mu_k = 0.1$
Ice/Ice - $\mu_s = \mu_k = 0.01$
See table here.
- 8,232
3
votes
Accepted
Why is the open-front bike stem design so widespread despite that it may be inferior to the closed-front design?
For starters, I think you have to differentiate between "theoretically inferior" and "practically inferior". Judging by the hundreds of thousands of bikes with open-faced stems out ...
- 162
3
votes
Accepted
Will this pulley system work?
Yes.
If the motor moves to the right by distance $x$ then the inner left pulley most move the same distance.
This will increase the length of the fixed end by $x$ and the length of the top left ...
- 11.1k
2
votes
Good material for friction disk for a torque hinge?
Gem Products friction hinges use a sandwich of different metal washers, for example, phosphor bronze, stainless steel, and phosphor bronze. Their patent says:
The washers 135 of the present ...
- 51
2
votes
Accepted
Recreating Focaults Pendulum
There are two simple options for the bearing
The first is to suspend the bob from a flexible cord passing through a fairly tight grommet so it will maintain a constant point of contact in all ...
- 15.3k
2
votes
Brake pad materials for use against an aluminium surface
Just remember that "soft" materials wear "hard" ones : brake pads on cars wear the steel discs... So, the aluminium will wear as it is friction based.
Edit : What about a water dynamometer? Ie ...
- 16k
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