Questions tagged [friction]

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26 questions with no upvoted or accepted answers
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7
votes
1answer
335 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 ...
4
votes
2answers
846 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 ...
4
votes
0answers
128 views

Calculating a pull force between two pieces of plastic

I have an HDPE pin, 2 mm high, 2 mm diameter, that I impress into a flat plaque of hot HDPE. It is not hot enough to melt the pin, but still hot enough that the material will shrink 4% in 24 hours. ...
2
votes
3answers
100 views

Forces acting on a weightless member

A weightless bar is pinned at the top of a triangle with N weight. Both rests at the horizontal plane. There is a horizontal force F acting on the weightless bar, and a given coefficient of friction μ ...
2
votes
0answers
529 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 ...
2
votes
1answer
78 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" ...
2
votes
0answers
63 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 ...
2
votes
0answers
96 views

Torque needed to keep a wheel spinning at high RPM

I have a treaded wheel which is 16'' diameter and 4'' across (trailer wheel). If I want it to spin constantly at 2750 RPM, what amount of torque do I need to apply to combat friction and air ...
2
votes
0answers
59 views

how to calculate the speed ratio (Rotational speed to advancing speed) in friction stir welding

I am a student and I work in the friction stir welding of a hardened aluminium alloy 7075-T6, and I want to confirm about this information before I put it in the article. I found in the literature ...
1
vote
1answer
53 views

Pressure drop in a CFD simulation of an air flow too small

I am simulating a turbulent air flow through a rectangular channel with the goal to match measured velocity profiles and the static pressure at certain points. My problem is that the pressure drop in ...
1
vote
0answers
33 views

Force necessary to resist motion due to torque on a drum brake

A drum is subjected to a counterclockwise torque of 16 in-lb. What horizontal force is necessary to resist motion? Coefficient of friction = 0.40 Weight is neglected. I'm having a hard time on this ...
1
vote
2answers
65 views

Find frictional losses as box exits ramp

I have a box traveling on a ramp just before the ramp levels out. At this point all values are known: I want to calculate the frictional losses from this point to when the box is completely off the ...
1
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0answers
33 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 ...
1
vote
0answers
32 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 ...
1
vote
1answer
106 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 ...
1
vote
0answers
204 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 ...
1
vote
0answers
62 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 ...
1
vote
0answers
53 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 ...
1
vote
0answers
73 views

Spinning a balanced load with DC motor

Enclosed within a consumer electronic, I would like to spin a small balanced load. The device will be rotated relative to gravity, but no other direct forces will be applied to the load. A coreless ...
0
votes
3answers
45 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 ...
0
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0answers
52 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 ...
0
votes
1answer
51 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 ...
0
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0answers
34 views

Cases in finding the maximum weight of the block

I am dealing with this problem about belt and dry friction. I need to find the maximum allowable weight of block B to maintain static equilibrium. I have given value of weight of the block A. The line ...
0
votes
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 ...
0
votes
0answers
30 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 ...
0
votes
2answers
108 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 ...