Questions tagged [friction]
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Self Locking Brake Question
I've been staring at this problem for statics for quite a while now and I just don't understand it. The question states:
"The brake is to be designed to be self locking, that is, it will not ...
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Friction coating aluminum parts in lieu of anodizing
I have an application, 6061-T6 aluminum cylinder, and piston - approx 6" dia for both, O-ring on position. The piston is under 80-100 psi, room temp and stroke are a couple of inches.
Typically, ...
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Will this pulley system work?
I want a system to move something in the opposite direction to the driven thing, but twice the distance. I'm thinking the below system of pulleys. I just wonder if it will actually work or will it ...
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Pivot Point with Low Friction
Inspired by this question, I am looking for a low-friction pivot for a clock pendulum. The design uses magnetic repulsion to keep the pendulum going. A magnet is attached to the bottom of the pendulum ...
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What would be the Force Balance on this situation:
I'm struggling to find the correct Force balance in the following situation:
The black parts are hard stopers.
The blue part is moving perfectly aligned with the Y-axis in the negative direction.
The ...
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Why is friction problematic on small mechanisms with multiple parts?
This recent video concerns scaling down a nerf gun. Apparently a major problem (mentioned at 2:46) is the fact that friction "multiplies exponentially". Can someone explain more precisely ...
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Minimum power required to drive a vehicle with a Swedish type omni wheels
I'm trying to find the minimal power needed to drive an omidirectional 3-wheeled robot. I already asked in Robotics Stack Exchange and they didn't respond yet.
From the equation $P=Fv$ I know I need ...
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How can I reduce noise from pushrods in an assembly without using grease/oil?
I have an assembly which consists of a row of vertically-oriented nylon pushrods (each 5/16" in diameter, colored green in the attached pictures), and two black pieces of laser cut delrin ...
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Why carrom coins have the circular profiles on them?
Why do carrom coins have these circular profiles on them? At first I thought that this will reduce the friction as area reduces, but quickly recalled that friction for solids don't really depend that ...
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How can I reduce static friction in a small rotary encoder?
-- Note: I've flagged this as unlikely to be a quality question. I've refined it and rephrased it as a Mathematics SE focused one instead. Find it here.
I am using a rotary encoder as a pivot point ...
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Why robotic Lawn mowers are curved body structured?
Why robotic Lawn mowers are curved body structured as shown in image ? Is the curved body structure called aerodynamic ? What's the technical reason for it ?
For reference image :
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Modelling friction and its application to generalised forces in the Euler Lagrange equations in a 2D Unicycle model
I am in progress of building a simplistic 2D model of an electric unicycle with the intention of creating a stabilizing controller. The EUC can be modeled as an elaborate inverted pendulum and the ...
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Unwinding a spool that does not slip on a conveyor belt
thank you for taking a look at this problem, as I do not want to plagiarize the textbook I am using I will break down the problem, state the textbook's final solution values, and my question about ...
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How to stop a leg from sliding?
One of the legs of a bed is bent (I believe it buckled). The bent can be corrected to be straight, however under the application of load to the bed, the leg will slowly return to the bent position. My ...
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What would be an ideal material to use for O-rings on a canister in a lubricant-less, high-velocity pneumatic tube system?
I am interested in building an experimental lubricant-less pneumatic tube system in which the canister will be propelled up to a high-velocity, reaching a peak velocity of approximately 100 m/s before ...
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Where would I place a bearing between 2 surfaces?
I'm a high-school engineering student, and for my final project I wanted to make a robotic arm.
However, I'm stuck on how to minimize friction between 2 surfaces (both made out of aluminum 6061-T6) ...
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Calculate pipe size and friction loss for an agricultural project's water system?
I'm in the process of designing a water system for our regenerative agricultural project in the Horn of Africa.
I'm looking to install a ≈1000L water tank on a 3 meter stand which will gravity supply ...
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Can epoxy bond two Aluminum alloy beams?
The bicycle component manufacturer Shimano makes crankarms named "Hollowtech".
Hollowtech crankarms are meant to be both strong and light. As the diagram below (source: Shimano) shows, the ...
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Dynamic forces in Simulink
I have the equation of motion:
$a = \frac{1}{m} \left( F_1 - F_2 -F_{fric} \right)$
where a is the acceleration and m is the mass of an object. $F_{fric}$ is the friction calculated as:
$F_{fric} = B \...
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Why is the open-front bike stem design so widespread despite that it may be inferior to the closed-front design?
Context
Even major bicycle corporations have the occasional
product recall on handlebars.
It's easy to see why. The bike itself is a gentle, light, and nimble ~10 kg (for a road bike) object, whereas ...
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Smallest possible rolling resistance
So, question is how to achieve the lowest possible friction in a scenario where there is a steel bar rotating AGAINST the circular frame at high rpm. Now, when it comes to sliding friction lowest ...
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Force Required to Keep Ball Rolling
I am attempting to recreate a demonstration that someone told me about. A hollow steel ball rolls around in a non-metalic bowl, electromagnets keep it going. I obtained a steel ball and a glass ...
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Collecting a released rope with a proper speed
To simplify the problem, I liken the problem to a ship approaching the shore and a device wants to collect the rope in such a way that the rope is neither stretched too much nor released to the extent ...
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Can you explain mathematical and mechanics formulation of equation in Junker 1969 paper on self-loosening of fastener by vibration?
Can you help me to understand how the first equation in the paper 'New Criteria for Self-Loosening of Fasteners Under Vibration' by GH Junker, 1969 is derived? I'm not able to understand the ...
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Most efficient electricity generation in a wide flow of water
I'm wondering what the best method is for generating electricity in a wide river. The assumptions here is that it's a strong flowing river. It is very wide and we're allowed to put an electricity ...
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Can Friction Pendulum Bearing/System (FPB/FPS) suppresses the effect of an earthquake from every direction or only from one direction?
Can Friction Pendulum Bearing (FPB) AKA. Friction Pendulum System (FPS) suppresses the effect of an earthquake from every direction or only from one direction?
Please take a look at the tests which ...
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Passive magnetic bearing coefficient of friction
Imagine two axially-magnetized ring-shaped permanent magnets in a repulsive configuration where one is levitating on top of the other (and somehow radially constrained so the PMs remain ~concentric). ...
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Do asperity junctions break every time a machine starts to rotate?
After reading CONTROL OF MACHINES WITH FRICTION by Brian Armstrong-Helouvry, some questions rised.
The main question I ask you is:
Suppose two metal surfaces in relative motion first in static ...
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How to create a friction-based cable exercise machine?
What would be the best mechanism to create a friction based cable machine? The point of this machine to only have resistance to movement not when the cable's stationary and without the momentum of ...
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To reduce friction losses, is it better to have one single large ratio stage, or multiple smaller stages for worm gear?
If I wanted to have a 49:1 total reduction, would there be less friction losses with a single stage of a 49:1 or two stages of 7:1 and 7:1?
Google has not been much help. My gut says that I should use ...
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How friction between stator and rotor is dealt with in an electric engine/motor
This YouTube video https://www.youtube.com/watch?v=nlG2dsYRagI shows how an electric engine is made but I don't understand how friction between the stator and rotor is dealt with.
At 3:50, we see the ...
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One way locking mechanism linear movement
Sorry for the English in advance, it is not my native language :)
I am working on a design which involves moving two steel plates in a horizontal linear motion together to clamp around a box. After ...
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How to calculate press load for an interference fit with no friction coefficient between the materials (shaft & hub)
Press-fit load calculation always takes friction into consideration and gives you the load expression as follows,
$$F = µ\cdot PA$$
where µ is the friction coefficient, P (Interference Pressure) is ...
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Examples of Materials with a Coefficient of Kinetic Friction Very Close to or Equal to Coefficient of Static Friction?
I'm looking for examples of frictional materials that have a coefficient of kinetic friction that is as close to equal to their coefficient of static friction as possible.
What is an example of that ...
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Rack on rack vertical force
I have a locking mechanism in mind, that is made with two racks.
Rack 1 is fixed and then we push down rack 2 to lock something. After that a horizontal force is applied to rack 2. I calculated the ...
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Head loss coefficient for a valve with respect to both the open position and flow rate
This question talks about the head loss coefficient for a valve, i.e., $K_{L}$ for $h_{L} = K_{L} V^{2} / 2g$ where $h_{L}$ is head loss.
First, head loss coefficient for a valve with respect to the ...
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Derivation of static & kinetic friction formula
We know formula of static friction & kinetic friction = μsN and μkN.
I have searched online a lot about them.
I do know what is the formula & how to use it but I couldn’t find any article ...
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On Which Side Will The Tyre Wear Out More?
Whilst watching a F1 race recently I noticed the commentators talk about how all the cars on that race day started observing more/faster wearing down of the tyres on the front left of the car relative ...
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Eliminate cat ear and nose shocks during the dry season
My cat, George Valentine, really enjoys being pet. However, when the air here in Canada gets very dry (mid-fall), this activity creates static charges. Once the petting starts giving him relentless ...
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Which of these two cases will have the most friction?
I have a structure colored in blue which we are looking directly downwards on (birdsview). Its high up in the air, and the only thing keeping it from falling down is the friction surface (red) between ...
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What rubber to use to grip stainless steel?
I need to secure a plastic bobbin on a 316SS shaft so it can be wound in a winding machine. There is a potential for undesirable axial and rotational drift that I need to prevent.
My initial thought ...
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Water dynamics in aluminum pipeline for dummies
This topic is totally alien to me, so I may be asking something very obvious.
I am designing a cooling system. In the bulk of aluminum, I drill 3mm holes and then I connect them one to another to ...
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Is there a positive displacement pump that experiences only rolling resistance?
Is there a positive displacement pump that experiences only rolling resistance? One with no sliding friction and diaphragm stretching?
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Equivalent viscous damper for friction damping
I have a friction damping system which is exited by a harmonic force FE (depicted on the left side).
Is there a way to convert the friction damper to a linear or nonlinear damper, such that the ...
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How much actual performance is lost with extreme negative camber / "stanced" vehicles?
I recently had a discussion with a friend, who's intuition is that "stanced" cars with extreme negative camber angles are losing a huge fraction of their performance, such that a 5.0L V8 ...
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Rover Steering Torque
I would like to calculate the required motor torque to turn a rover wheel whilst the rover is stationary. I have modelled the friction force as a distributed force acting equally along the width of ...
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Inconsistant load cell readings - (static) fiction perhaps?
First off I'm not an engineer so please excuse the simple language I use to explain my question!
I have an arrangement whereby I have a steel plate suspended from basically a bridge. The plate is free ...
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Friction in Wedges: finding the mass of the block C on the verge of slipping
I need to solve for the mass of block C that is in the verge of slipping. All surfaces have a coefficient of static friction of 0.11. The cable connecting the wedge B and C is parallel with the ...
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Determine the minimum horizontal force to disturb the equilibrium
Three blocks of 1N 2N and 3N are placed one over the other respectively. If the friction between the topmost 1N and the middle 2N block is twice the friction between the lowest 3N and floor then ...
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How to guess direction of friction in any case
Here , in case of a death well situation as an example.
Q How is direction of friction going to be opposite to mg or in upwards direction ?
Why not:
In case of like circular turning , direction of ...
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