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Questions tagged [friction]

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Why do engines with cylinder offset not suffer from increased frictional losses on the compression and exhaust strokes?

I recently watched the D4A YouTube video on cylinder offset, and for the most part it makes sense. Longer power and intake strokes, lower frictional losses on the power and intake strokes, greater ...
Ryan W.'s user avatar
1 vote
0 answers
20 views

If building a DIY screw jack, would it be beneficial to add a gimbal to the jack nut, and/or to the screw attachment?

The screw jack will be used twice daily. It will be made out of M24 8.8 grade threaded rod and nut. The nut will travel 300mm, to raise a weight of 50kg by 800m, via a pivoting lever arm. The parts ...
Russel Walker's user avatar
3 votes
1 answer
67 views

Friction force between two wheels at constant rpm

I have two tangent wheels pinned at their centers /which coincide with the center of mass/ and torque is applied to one of them (both roll without slipping). I want to find what force would they exert ...
Statisticool's user avatar
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60 views

Belt conveyor roller spring

I wanted to know if anyone could help in this area. I want to create an inclined conveyor belt where, when a cargo box reaches the top of the conveyor belt, the rollers sequentially move down (maybe ...
ramine khadem's user avatar
0 votes
1 answer
54 views

How does the mechanics of left-handed scissors differ from right-handed/standard scissors?

So I've read that my right hand with a left-handed scissor "pushes the blades apart" (same with my left hand with right-handed/standard scissors), but I couldn't find out why this happens or ...
damacc's user avatar
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1 vote
3 answers
144 views

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 ...
Bob Flinn's user avatar
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0 answers
28 views

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, ...
ShelleyG's user avatar
1 vote
1 answer
64 views

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 ...
Oliver Walters's user avatar
0 votes
1 answer
139 views

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 ...
Mattman944's user avatar
0 votes
2 answers
62 views

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 ...
Bruno Fernandes's user avatar
1 vote
1 answer
60 views

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 ...
Benjamin Wang's user avatar
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1 answer
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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 ...
Radar32's user avatar
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0 answers
40 views

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 ...
user10264746's user avatar
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0 answers
62 views

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 ...
Suryakant Thakur's user avatar
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2 answers
115 views

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 ...
Wossname's user avatar
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2 answers
58 views

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 :
robin's user avatar
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1 answer
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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 ...
Babu's user avatar
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1 answer
69 views

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 ...
user57467's user avatar
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0 votes
1 answer
116 views

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) ...
Kendrick Lee's user avatar
0 votes
0 answers
80 views

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 ...
Jonathan Ciccarone's user avatar
1 vote
2 answers
105 views

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 ...
Sam7919's user avatar
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1 vote
2 answers
251 views

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 \...
Nil's user avatar
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3 votes
1 answer
85 views

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 ...
Sam7919's user avatar
  • 441
0 votes
2 answers
140 views

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 ...
Nix's user avatar
  • 1
0 votes
1 answer
101 views

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 ...
Mattman944's user avatar
0 votes
2 answers
31 views

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 ...
Ali Sheikhpour's user avatar
0 votes
1 answer
117 views

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 ...
Khushal Badhan's user avatar
0 votes
2 answers
121 views

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 ...
Trioxidane's user avatar
0 votes
1 answer
32 views

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 ...
itsazzad's user avatar
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1 vote
2 answers
94 views

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). ...
MehranJ's user avatar
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0 answers
41 views

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 ...
el_maxx's user avatar
-1 votes
2 answers
156 views

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 ...
bacon_is_good's user avatar
0 votes
2 answers
81 views

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 ...
Zeno's user avatar
  • 1
2 votes
1 answer
253 views

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 ...
Aminos's user avatar
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0 votes
0 answers
569 views

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 ...
Emma's user avatar
  • 1
0 votes
2 answers
2k views

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 ...
Kaushik's user avatar
  • 51
0 votes
1 answer
224 views

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 ...
Prithvi Boinpally's user avatar
0 votes
3 answers
147 views

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 ...
Grega's user avatar
  • 35
1 vote
1 answer
2k views

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 ...
J. Choi's user avatar
  • 121
0 votes
4 answers
1k views

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 ...
S.M.T's user avatar
  • 679
1 vote
1 answer
43 views

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 ...
Rishi Chauhan's user avatar
2 votes
3 answers
89 views

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 ...
James Orr's user avatar
  • 121
0 votes
3 answers
113 views

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 ...
greatoak763's user avatar
1 vote
1 answer
203 views

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 ...
Ben Booth's user avatar
0 votes
1 answer
63 views

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 ...
Gregory Kornblum's user avatar
2 votes
3 answers
84 views

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?
Francis L.'s user avatar
4 votes
3 answers
455 views

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 ...
M. Martin's user avatar
  • 143
0 votes
0 answers
86 views

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 ...
Ehryk's user avatar
  • 101
0 votes
1 answer
276 views

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 ...
Bailey's user avatar
  • 1
0 votes
1 answer
52 views

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 ...
KevInSol's user avatar
  • 117