Questions tagged [friction]

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2answers
172 views

How to add friction to a rope without using abrasion

I have a pay-out winch. It is a spool of rope that has a disk brake attached to it, so I can control the torque required to rotate the spool. When the torque is very large, however, the rope begins ...
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1answer
51 views

Calculating Bending Force on a Fixed Metal Plate

At work we've had a steel pipe support break on us, and I can't for the life of me figure out what happened. Here's some background info: A long (125m) steel heating pipe (ø51mm) is suspended, resting ...
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2answers
36 views

Disc Brakes - Swept Area , why is larger better?

I am trying to understand why a bigger swept area on disc brakes provides higher braking force for the same force being exerted on the brake lever/pedal by the rider. If we use the same exact brake ...
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3answers
156 views

Why is the friction factor in laminar flow independent of pipe roughness?

The Darcy friction factor is defined as: $$f_D =\frac{64}{Re}$$ with $Re$ I mean Reynolds number (global). I was wondering why Darcy in laminaire flow is independent of pipe roughness (wall roughness)?...
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2answers
50 views

Acceleration of spool on conveyor belt

A spool has a mass of 500 kg and a giration radius of $k_G = 1.30m$. The spool lies on the surface of a conveyor belt, the static coefficient of friction is $\mu_S=0.5$. The spool is not moving at ...
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0answers
26 views

Where do I learn about jewel bearings?

I would like to take a deep dive into the world of jewel sourced watchmaking components (including, but not limited to, bearings) but I am having trouble finding any textbooks on the subject. Are ...
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1answer
31 views

How is forward motion initiated in this case?

Source:byjus.com Do these forces cancel out each other? If yes, how is forward motion initiated? Also, in this situation, since friction between the road and the wheels is enabling motion, which ...
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1answer
39 views

How does the friction on the front and rear wheels of a car vary?

Consider a Rear-Wheel Driven car. The questions refer to friction between the wheels and the road. 1.Direction of friction on the front and rear wheels when car accelerates? Is it static or kinetic? ...
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3answers
36 views

Need help regarding working of drum brakes

I was learning about the working of drum brakes, and I came to know, that each of the two brake linings of drum brake apply horizontal force in opposite directions. That confused me, because, if ...
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1answer
37 views

Why Does Particle Size Matter For Bridge Pillars here?

I was watching this engineering video here and it talks about a technique used to prevent the pillars of a bridge from falling over in an earthquake. The pillars of the bridge are partially submerged ...
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1answer
22 views

clamp force or torque for non-steel screws - brass or aluminum

It is common for screw tightening to have the relationship between torque and clamp force defined by: $$T=kFD$$ However, all the calculators seem to assume the screw is steel. How can this be ...
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0answers
20 views

Train decelerations in no power condition

Suppose a train is running at 30kmph and suddenly the power is switched off. How do we calculate the reducing velocity at intervals and what factors will affect the change in it?. Further how much ...
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0answers
17 views

Bevel gear friction and inertia calculation

I want to calculate the friction and inertia between 2 bevel gears with straight teeth. I know how to calculate those parameters between regular gears with straight teeth. Is there any difference for ...
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1answer
28 views

Inertia and friction between gears

I have a question regarding inertia and friction between gears. I have a gear which is connected to the rod at one end and an electric motor which is connected to the other end. I know the torque of ...
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1answer
69 views

Hydraulic Brakes - Why motorcycle brakes more powerful than bicycle brakes?

I was wondering why motorcycle brakes have so much more stopping power than bicycle hydraulic brakes (Than can be found on mountain bikes for example). The rotor has a bigger size which gives better ...
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1answer
155 views

Calculate max deceleration without front wheel slipping (bicycle)

I am trying to calculate the maximum braking force/deceleration for a bicycle. Note: the question assumes only the front brake is used Free body diagram: For dry tarmac where I know there is enough ...
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1answer
19 views

Formula for finding the optimal weight for a given torque and vice versa

Whenever i see videos of two trucks pitting with each other to see who has a stronger, i always see comments that sounds like: If you load the other truck more it would beat the other one That truck ...
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1answer
35 views

What is the average energy loss due to rolling friction in contemporary motor vehicles?

Around what percent of energy provided by gasoline is lost as heat due to rolling friction in vehicles? Is this number higher for larger vehicles likes trucks than smaller vehicles like bikes? ...
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1answer
28 views

What is the minimum frictional force required for a vehicle to operate smoothly, retain traction, and prevent any skids?

I am not looking for a specific number of course. I know that it may perhaps vary with different vehicles. However, I'm trying to figure out how to theoretically calculate the minimum necessary ...
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2answers
168 views

What is the exact concept of bearings?

Mechanics books always highlight that the main advantage of bearings is to reduce friction, especially when we talk about them in rotational motion applications. The example of ball bearings is always ...
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1answer
70 views

Calculating optimal angle on a rolling pulley wheel, which holds weight, on a horizontal cable

The 40 kg load on the rope accelerates from 0 to 50km / h in 6 seconds. The rope is tightened with a force of 500kg while the whole assembly is on it. The middle pulley is driven by a dc motor. I ...
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0answers
171 views

how to calculate required torque and rpm to through a 160 gram cricket ball horizontally at 160km/h velocity?

I am going to design a bowling machine. In this design, I'm going to use two motors that are being placed vertically and their shaft are attached with two horizontal identical wheels with a space of ...
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2answers
64 views

Faster car drifting (motorsport) when using limited slip vs welded differential

I have been drifting RWD (rear wheel drive) cars for some years now. I tend to think about every engineering solution that other drivers use and how does it work before applying it to my car. What ...
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3answers
185 views

Why is the Bush of a motor not replaced with a ball bearing?

Ball bearing reduces friction to a large extent than sliding friction. Motors use a metal ring called bush which slides against the shaft when the shaft is rotating. If a force is exerted on the shaft ...
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0answers
28 views

What type of bearing should I use to allow a ring to rotate around a fixed axle

What type of bearing should I use to allow a ring to rotate around a fixed axle. Axle is horizontal. The rings inner diameter can be flush with the stationary rod or have a gap as needed. What type ...
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1answer
82 views

Friction factor for wormgear design materials

I'm working on a database which involves geometric design parameters, forces analysis and efficiency and losses for wormgear reduction design systems. To determine the tangential and axial forces ...
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2answers
50 views

How to calculate traction force w.r.t. rotational speed of a shaft mounted at a certain angle on a surface?

I am designing a new mobile robot platform and i need a generic solution for the robot in order to establish a proper mathematical modeling. My question is about calculation of the traction force of ...
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3answers
158 views

Dead mans brake on a hand-pushed wheelchair

Would it be possible to install a dead-mans brake on a wheelchair? I have been calling around and wheelchairs do not seem to come with a dead-mans brake. With that i mean the brake found on airport ...
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1answer
68 views

Pacejka “Magic Formula” tire models origin of the name

It might be a little off topic but I'm trying to find source for why is that model called magic formula? I read that it's a simple function of commonplace functions, a data fitting. Is it simply an ...
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2answers
115 views

Refute my assumption: Bearings Don't Improve Efficiency

If two surfaces rub together with a normal force between them, friction is generated. You could add lubrication between those two surfaces and reduce that friction. Bearings essentially consist of ...
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2answers
47 views

How to keep lighting “barn doors” open

I have two alum plates (45cm x 20cm x 1mm) that are hinged on the long side with two 30 x 80 hinges (30 x 40 each tang) in the middle, and "L" bracket / 20mm brace at the ends secured with a M4 loc ...
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1answer
76 views

What are fluids or “goos” called, that increase friction?

I have a shaft inside a bushing, the shaft has a gear on one end that is supposed to provide resistance to other gears it is driven with. I'm having a hard time finding the correct term for the sort ...
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2answers
65 views

Which design to maximize friction for a device standing on concrete?

I have a device 4cm X 5cm X 15cm that stands on asphalt/concrete/road. So, the device is taller than its base which makes contact with the asphalt. I want to maximize the friction so that the device ...
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1answer
53 views

Effect of friction (or horizontal motion) on vertical surface deformation

I am trying to model the dynamics of some system. In summary, the system consists of one horizontal linear actuator that drives an object along a planar surface and one vertical actuator that brings ...
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1answer
49 views

How do you calculate the chain tension required when compressing bulk material over a conveyor?

Bulk material is conveyed over a slat conveyor, and the material is leveled with overhead rollers while being transported in the conveyor to maintain an even material height. Most of these "levelers" ...
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1answer
97 views

Minimum required rolling friction between pulley and the rope

The 40 kg weight accelerates and runs on a rope from 0 to 50 km/h in 10 seconds. I want to calculate the minimum required rolling friction that I need (acceleration without slipping) to achieve ...
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0answers
42 views

Regarding the ITTC Guidelines for Ship CFD applications

I was reading through the ITTC – Recommended Procedures and Guidelines - Practical Guidelines for Ship CFD Applications (https://ittc.info/media/4196/75-03-02-03.pdf) document and this little thing ...
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1answer
229 views

Material with strongest grip on Aluminium 6061

Attached is an example picture of a clamp that will be attached to a pipe made of Aluminium 6061-T4. The clamp should have very tight grip on the pipe and prevent it from slipping or rotating but the ...
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0answers
148 views

statics exam question about friction

In a statics exam I had the question in the picture attacehd and I had some trouble understanding it. The question is so Under the effect of torque Mo rotates a wheel (radius r) with constant ...
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1answer
121 views

Ideal funnel design for powders

I'm designing a funnel/bottle for a powder. My goal is to have all of the bottle's powder contents come out when inverted. However, the powder has a tendency to stick to itself (like flour or brown ...
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0answers
47 views

Why increasing the coefficient of friction results in evenly distributed load in rolling machines?

I'm designing a rolling machine for reduction of steel ingots of $5 mm$ to $1.96 mm$ thick. I can convince myself using equations why increasing the coefficient of friction (in case of lubrication ...
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1answer
1k views

How to find required clamping force of bolts to prevent flange faces from twising due to torque?

I have a gearbox adapter that bolts onto a flange and I need to work out how much clamping force is needed to prevent the faces from slipping and keep the bolts in tension rather than shear when ...
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2answers
187 views

Does a washer really increase static friction force?

Suppose I have a bolt that goes through a hole in a plate and is under tension. If I place a washer between the bolt head and the plate, does static frictional force (torque actually) really double? I'...
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2answers
326 views

Materials to use for a low friction cable-pull

I'm posting this question on this stack-exchange site, because it appeared to be the one made for this kind of questions. If this happens to not be the case, I'm sorry, I didn't know better. Also ...
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0answers
460 views

How Can You Calculate Force to Overcome Friction From an O-Ring Seal?

I essentially have a piston in a tube that is sealed with an O-Ring and actuated with a solenoid. The friction of the O-Ring however, is higher than estimated (guessed as far as I can tell) by the ...
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1answer
202 views

Pan and tilt mechanism

this is my first project that i am working on. I want to make a IR sensor mount using stepper motors. I seen this on youtube and would like to make a similar design. I plan on using aluminium ...
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0answers
40 views

How to make machined plastic part slippery for small dry particles

We have a plastic part that is a receptacle for small ( < 1mm ) particles. It is a disk with a shallow cone shaped indent made using a drill. When a particle is placed in the receptacle it should ...
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2answers
287 views

Mechanical device that creates friction when rotating?

I am designing a mock-up aircraft throttle, like one of these: In an airplane, it it slides forward and backward to control the thrust of the engines. The problem is, I am not sure how to go about ...
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2answers
246 views

Multilayered Bearing Spinner

I have a few questions relating to a multiple layered spinner that uses ball bearings to reduce friction, kind of similar to a fidget spinner. The image below is an example of the multilayered bearing ...
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1answer
261 views

Deriving the amplitude of a coulomb (dry friction) damped spring

This is my first time posting anything, but I could not figure out the derivation of the amplitude of the spring for the 4 first oscillations. I am not acquainted with the effect and calculations of ...