Questions tagged [mechanical]

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8
votes
3answers
3k views

Mechanical advantage of the 3-ring release system

I'm quite curious about the 3-ring release system used in parachutes, as described in this Wikipedia article: https://en.wikipedia.org/wiki/3-ring_release_system I wonder why is this system so ...
6
votes
1answer
135 views

Identify this bomb disposal equipment

A recent news item featured this photo of a WW2 bomb being prepared for detonation. Can anyone identify the purpose of the large widget sitting on the bomb? it's got a lot of cooling fins on it, and ...
3
votes
2answers
7k views

What is Saint Venant Principle?

I am having problem with the application of Saint Venant principle.I have heard that quite often we use that knowingly or unknowingly.I would be very greatful to anyone who would explain this very ...
3
votes
3answers
3k views

Moments of Fixed-Fixed Beam

I have a quick question related to the topic of mechanics of materials. If I were to have a beam that is fixed at both ends and has a central point force, do moments develop at the fixed supports? e....
3
votes
3answers
283 views

Torque and RPM calc

started by designing the gear meshing, and now I need to calculate some parameters to determinate if this meshing works for me. The system considers an electric motor, which technical parameters are: ...
3
votes
1answer
49 views

Clutch role in a micro hydropower

I've recently visited an old (about 60 years old) micro hydroelectric standalone installation. Total electric power is about 3 kW A/C. A local told me between generator + fly-wheel and turbine there ...
3
votes
2answers
935 views

Why do 2-stroke engines burn more oil?

Of course, most 2-stroke engines require oil to be mixed with the fuel (I appreciate there are 2-stroke engines that don't require this). Therefore, it makes sense to me that oil will be burnt during ...
3
votes
1answer
47 views

Scanning and modeling my personal vehicle for aerodynamic simulation

I have this pickup truck that I love dearly. I often change the aerodynamic configuration of the truck when I use my camper shell, or roof top tent, etc. Is there a reasonably easy way to create a ...
3
votes
1answer
399 views

4 Gears in a Circular Pattern - Calculating the Proper Distances for Meshing

I have recently been working on a gearbox for a robot. I have this pattern of 4 gears with each gear connected to its 2 neighbors. It looks like this: You will probably notice something though. ...
3
votes
1answer
332 views

Quick return mechanism for spring-loaded screw

Looking for a way to convert rotary motion to linear, but it should take less energy to get back to initial position than when going from initial position to the end position. Specifically, a screw ...
2
votes
3answers
75 views

What is this mechanical pump called?

I am unable to find it again but I once heard of a type of air pump that involved a pair of offset archimedes screws inside a cylinder. The point of the device was that as the screws would turn ...
2
votes
2answers
269 views

Explain tolerances in technical drawing

I'm not a mechanical engineer and am not used to looking at mechanical drawings. I'm trying to understand what these tolerance features mean. There is a positional tolerance feature, which ...
2
votes
4answers
703 views

When calculating a force, why do I get different result when I try to calculate via torque vs via sum of forces at an axis?

If I just do it by writing that the sum on y axis is 0 I get $100+x=200$ $x=100$ If I try torque around the top: $x*800=200*500$ $x=125$ So what am I doing wrong?
2
votes
1answer
205 views

Vehicle Train Towing [closed]

Why can I not tow 50,000 lbs (40,000 cargo and 10,000 Trailer bed) using multiple pickup truck each individually capable of towing 30,000 lbs? I was told that the towing capacity does not "Add up" ...
2
votes
1answer
51 views

Is there a way to convert a short throw in one direction into a long throw in two directions

I have a motor that I have created a simple adapter for; this lets us attach any parts we might design to solve the final problem: I would like to convert the motors motion to oscillating motion in ...
2
votes
2answers
165 views

How does a two dimensional elevator work?

If you watch this video, you can get a sense of how an elevator can operate in two dimensions. But, what I can't figure out is how it is driven. If you consider a conventional elevator, there is a ...
2
votes
1answer
120 views

How did the snifting valve in Newcomen's steam engine work?

Its function was to expel the air that came inside the cylinder along with the steam to prevent the engine to become "wind logged". Since the valve was non-return, how did Newcomen stopped steam from ...
2
votes
1answer
105 views

Latch Mechanics

I want to make a sprung latch mechanism which keeps a door in place until a certain force is applied to the door. In the diagram attached, the force the door must release at is Fd, and the latch ...
2
votes
3answers
544 views

One way/locking mechanism without springs or flexible members

There a few neat mechanisms that allows only one way motion without the use of a pawl or ratchet. This is one of them: https://www.instructables.com/id/LEGO-Technic-One-Way-Gear-Mechanism/ What I'm ...
2
votes
1answer
50 views

Hinge or similar that breaks at a certain change in acceleration?

Suppose I have a rope that is capable of lifting 100 Kg without breaking. But I would like the rope to break if it is exposed to a sudden change in acceleration (jerk). So if the rope was lifting 10 ...
2
votes
2answers
949 views

How to calculate the gear ratio of planetary gear?

I saw this picture today: They give an ratio of 5/352. I think this is not possible with a simple gear. Maybe the upper sides ratio is the cause for it. Which formula do I need to calculate the ...
2
votes
0answers
71 views

How is motor torque related to capstan equation?

I know that capstan equation relates $T_{in}$ and $T_{out}$ as $T_{out} = T_{in}e^{u \cdot F_c}$, where $u$ is friction coefficient and $F_c$ is wrap (slip) angle. In my situation, the capstan is ...
2
votes
0answers
14 views

Is inverse hall-petch relation valid crystals larger than nanocrystalline?

The image shown here is of ceramics, where they varied the grain size and measured the strength. For example, let's take Al2O3. There we observed that strength first increased from 3 μm to 95 μm. But ...
2
votes
0answers
149 views

How to calculate torque requirement for vehicle with Mecanum wheels?

What are the changes specific to mecanum wheels when calculating torque requirements for a vehicle. I have the data for the vehicles mass, top speed and top acceleration.
2
votes
0answers
39 views

Epoxy/Adhesive to bond solid wood and acrylic

I am trying to bond solid wood with with clear acrylic, with requirement to able to withstand shearing force, not more than 6kg over an area of 100 sq.cm. Have tried to bond with result of the ...
1
vote
5answers
297 views

What is a purpose of learning G-code?

I might be wrong here. The solid modeling done in CAD like Catia, NX, Solidworks,etc can be taken as input in CNC and the desired shape and size of piece can be obtained.The CAD itself convert the ...
1
vote
2answers
64 views

Professional threaded insert in plastic?

I'm getting some plastic parts (made with HDPE) CNC machined. A few of these parts require the addition of threaded inserts. I've printed the parts myself using a 3d printer and when I add the ...
1
vote
2answers
107 views

Which frame is optimal for children's bicycle trailers? tubular or rectangular frame and why? [closed]

I need to construct a 3D wooden bicycle trailer for Kids. The weight of bicycle trailers must also be light! The Frame should be made of wood. what criteria should I use to construct a Frame,Children'...
1
vote
1answer
62 views

Bending moment when there are no constraints

I faced this problem in an old book (Hall Allen S., Theory and Problems of Machine Design; 1961) The answer according to the book is 592 [in.lb], but I think the bending moment should be 0 because ...
1
vote
3answers
45 views

what to learn to design mechatronics device that move [closed]

I want to design an artificial leg for disabled people. The idea is design of a Device for patients with problems on one side of the leg from the knee down. This device first detects intent to move ...
1
vote
3answers
269 views

How much force/torque act on a wheel of a vehicle when vehicle moves a constant speed and suddenly got a bump or jerk?

I am working on disturbance rejection technique in a vehicle of a wheel. Suppose our vehicle moves with a constant speed 15 km/h. Since roads are uneven in nature, suddenly vehicle got a bump or jerk. ...
1
vote
2answers
59 views

Most efficient orientation of exhaust vents on top plate of chassis for air flow with regard to heatsink fins?

I'm looking for some advice from an ME or anyone who understands heat transfer,convection, etc. I'm currently laying out in Inkscape a top panel for an audio amplifier I'm building. Now, my question ...
1
vote
1answer
26 views

What are the characteristics of a motor that will generate current and is powered by a 30 cc, 2-stroke small engine?

Problem: I am trying to hobby-build a generator using a (old, working, throw-away gas, yard blower) 30 cc, 2-stroke engine. The 2-stroke engine will spin a motor and I want the motor to generate DC ...
1
vote
1answer
108 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 ...
1
vote
1answer
43 views

calculation of tension in curved chain for chain fountain (Mould effect)

https://royalsocietypublishing.org/doi/10.1098/rspa.2013.0689 A chain of some sort goes upwards, turns in a half circle (according to the drawn diagram), and goes back down. Focusing on the half ...
1
vote
1answer
27 views

How to constrain stepper motor inside case?

I have a stepper motor linear actuator assembly like this for example, but the stepper shaft seems able to move axially back and forth - hence when I change direction it has to do a few rotations, ...
1
vote
1answer
219 views

How do I find the vertical reaction forces?

The horizontal Force $A_x$ is easy but how did they get the vertical forces $A_y$ & $B_y$? I tried using similar triangles for the Force and length of the sides, somehow I can't manage to solve it....
1
vote
1answer
81 views

How to calculate the maximum starting traction force for a train with multiple carriages?

Suppose I have a convoy composed of the following elements: A locomotive with 4 driven wheelsets (2 wheels per wheelset and therefore 8 wheels). $n$ carriages with 2 wheelsets each. Assuming the ...
1
vote
1answer
26 views

Arrow on Activity (AOA) Network Diagram

I have question-related to industrial management, actually, it is a problem on arrow on activity network diagram. I tried to solve the question my self, below are the images. If I did any mistake ...
1
vote
1answer
62 views

What kind of magnetic water conditioner can industrial sinter plant use?

As you can see in the below shematic, the magnetic water conditioners can be used for the pipes of incoming process water on sinter plants to reduce surface tension of water and get fuel consumption ...
1
vote
1answer
109 views

Does turbulent river flow classify as uniform?

I found this meme in a facebook group on engineering concepts: I selected A (steady and uniform). In selecting A I assumed the width of the river to remain constant along its path and no parameters ...
1
vote
1answer
203 views

Locations of max stresses in a circular beam?

If a torque and axial force is applied to a beam with a circular cross section, where along the cross section of the circular beam is the location of the max shear stress, max bending moment, max ...
1
vote
2answers
100 views

Fusion 360 animation , contact sets

I was designing a whit-worth quick return mechanism, I have provided the contact sets but they fail when I try to animate. The contact set is defined for the crank and slotted link.
1
vote
2answers
156 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 ...
1
vote
1answer
158 views

Electric Motor Sizing : Understanding how much torque I need given Force

Physics has never been my strong point... I have a task to size a motor. The question is: Based on information below, how do I calculate required motor torque to accelerate a mass with the ...
1
vote
1answer
497 views

How to prevent an object doing a full rotation on a shaft

I basically need a block on a shaft to rotate between 90 degrees (vertical) and approximately 180 degrees (horizontal) counterclockwise on a shaft. I don't want the part to fall below 180 degrees. At ...
1
vote
2answers
118 views

Temperature dependent electricity consumption of HVAC System

I am trying to figure out if there is a decrease in electricity consumption of a cooling unit if the ambient temperature decreases from 35°C to 20°C. More detailed, a company is planning to install an ...
1
vote
1answer
53 views

Mechanical Engineering- Modeling contact in Abaqus

I have simulated a 2D model in Abaqus which indicates 2 main part, first a sector that represent as wheel and, second a rectangular that represent rail. the wheel and rail are in contact and wheel ...
1
vote
1answer
38 views

Planetary gearing

It is said when a planet gear revolves around a fixed sun wheel, the number of revolution it makes might be more than what appears to be logical. For example, if the planet and sun are fitted with 20 ...
1
vote
1answer
17 views

Looking for locking “lanyard” reel mechanism

I'm working on a system that requires a small cord (~3ft long) to retract up into a reel and lock in place so it cannot be pulled away from the reel. Sort of like a seatbelt mechanism after it's been ...