# Questions tagged [mechanical-engineering]

Questions within the problem domain of mechanical engineering. Mechanical Engineering can be a broad field; consider choosing more specific tags if they apply.

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### What are the change in forces with a ribbon under tension is twisted?

Consider pallet strapping. It has width W. When the strap is flat, it has some maximum breaking strength B. Now, let's put one twist in it over X feet. Mentally we have a VERY skinny isoceles ...
1 vote
174 views

### Orthographic Projection to Isometric Projection

How to construct this orthographic projection into an isometric projection? I really don't get the picture on how this orthographic projection turn into isometric projection. There's also some missing ...
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### Will hot object near ceiling vent create more draft?

As in the picture, we have a room with vents at the bottom to let cold air in and at the top to let hot air out. Normally the air flow is limited by the temperature gradient (correct me if I'm wrong). ...
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### Does a nut exist which is able to travel half the pitch (lead) of a screw for a full rotation of the screw

Say you have a lead screw rotating at a constant angular velocity. Without being able to adjust the lead screw pitch or angular velocity. Is it possible to use a nut which will only travel half the ...
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### How to fluidize sand inside a 55gal Steel Barrel?

Looking for recommendations on how to make a fluidized sand bed inside of a 55 gal steel barrel. I've seen many examples of it done with pipes but I am worried about the evenness of the fluidization. ...
30 views

### Examples of conversion from bidirectional to unidirectional torques/forces and vice versa

I am looking for examples in which bidirectional torques or forces are converted or could be converted to unidirectional torques or forces. The torques/forces can also be mixed (e.g. a unidirectional ...
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### How can I make sure that my outflow is the same as my inflow?

I have a basin that is 110 mm wide, 200 mm long, and 15 mm deep. The walls are 2 mm thick. It has water being pumped into it at a rate of 0.1078 gpm from one side. In order to ensure that this pan ...
• 1
45 views

### Deploying an Recording Instrument in a 3 - 5 m hole

I am trying to think of the best way to deploy an instrument in a 3 - 5 m posthole. The instrument is approximately 15 kg, and it shouldn't be dropped into the hole. The tricky bit is that the ...
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42 views

### Specifying Pump Max RPM

I am reviewing specifications that indicate: "Pump Maximum Speed, RPM (Estimated, manufacturer to recommend): 187". Another paragraph later on indicates the following: "Rotative speed ...
62 views

### Automated steering system for crash testing vehicles

To test crash barriers, we crash cars into them at a specific speed and angle. The car must hit a designated impact point within plus or minus X inches. I'm wondering if it is possible to build a ...
39 views

### Characteristics of a smooth belt

I want to replace a cylindrical pulley, so I came across a component called a smooth belt. Now this thing came with many differenent variations, from 2.00" up ...
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### Japan's Maglev Train propulsion and guidance system

Above image is taken from Japan's Maglev Train youtube video by Lesics at here. If the electromagnets along the two walls used for guidance of the train (So that it does not hit the walls) is made up ...
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### How do I complete this tolerancing problem? Can someone walk me through Part 1?

I have been trying to solve this using rules of Basic hole and Basic shaft calculations but I keep getting it wrong
1 vote
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### Controlled oscillation of a piano string by electromagnetic, mechanical, or other means

What would be a good way to actively control the loudness of an acoustic piano note over time after the note has already been struck by the hammer, such as by actively changing the amplitude of a ...
62 views

### Making a basic sprung mechanism that can withstand moderate percussive force

I'm making a game where you have to hit targets, kind of like whack-a-mole except the targets aren't actively actuated. I'd still like an element of mechanical "feel" to it, so I'm aiming to ...
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### Not able to make enclosure in DesignModeller

I have a Fusion 360 model that I imported into ANSYS Workbench Fluent as a .step file. I want to make an enclosure around it but it is giving me an error. The error doesn't occur if I choose just any ...
61 views

### Alternatives of rubber sealant cement for finalizing patch-plug repair on car tyre?

I am doing a patch-plug repair for a 2mm puncture injury on my car tire: I have two questions: 1.) The minimum I got at local stores (in India) is a 6mm patch-plug. Do I need to drill/cut the injury ...
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### Inverted pendulum PID: controller causes cart to move at constant velocity?

I am trying to understand the PID controller of an inverted pendulum on cart system through this MATLAB article: https://ctms.engin.umich.edu/CTMS/index.php?example=InvertedPendulum&section=...
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258 views

### Drafting - Specifying multiple hole quantities

First post in this stack but curious on if there is a 'right' answer (within Australian or ISO standard) for how to quantify numerous holes of same size/properties on a drawing. In the past I've seen (...
52 views

### Transportation and storage of atomic weapons

I’ve been reading into the ministry of defence recently, and my question in general is this: Considering that the UK and US have so many nuclear weapons, how do they: store the nuclear weapons (isn’t ...
100 views

### Unable to validate hypersonic flatplate case in DSMC SPARTA

I'm trying to learn a software called DSMC SPARTA. I'm validating the hypersonic flatplate case mentioned in one of the tutorials on the website (Page 17). This was my test case: ...
1 vote
663 views

### Braking system for a miniature ‘Drop tower’ rollercoaster

The tower itself is only max 400mm. Designing the lifting system isn’t the problem but slowing down the gondola is posing a slight problem, any suggestions? I have looked into using magnets but I can’...
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63 views

### modal analysis of a wind turbine

I have to do a vibration mechanics project for university and I was thinking of doing the modal analysis of a wind turbine, only I don't know how to evaluate the results I get. With what I should ...
1 vote
62 views

### Modeling of Wheel Rolling Resistance

I have been working on longitudinal tire model for a while and constantly encounter problems with the formulation of rolling resistance. Consider one wheel model coming down from a damp. It is a 2DOF ...
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1 vote
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### Extension of a cantilever beam composed of unbonded layers

The question of the magnitude of the vertical deflection of a cantilever beam composed of unbonded layers has been posted here, but I was wondering if there is an analytical way to solve for the end ...
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I'm in the process of building a simple led moving head like This ADJ Pocket Pro, my POC will be much simpler but you get the direction I'm going. Electronics are working, now I just need a proper way ...
23 views

### Would it be feasible to use the water vapor produced from hydrogen internal combustion engines to power a steam generator in a car?

In a standard internal combustion engine, exhaust temperatures typically approach 400-500 degrees Celsius for standard applications. If we consider that the primary exhaust gas of hydrogen engines is ...
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### Accelerate an object in a current-carrying coil

I'm currently trying to come up with some concept ideas for a physics game / riddle. The player has to get an object from one side of a horizontal, current-carrying coil to the other end of the coil ...
18 views

### How can I know the linearity/nonlinearity from the FRF result?

It's a FRF of neat PA 11 obtained by vibration test. (Mind that g is not a gram but the acceleration) Explanation says that for the excitation level of 5g, the FRF is strongly modified and the peak's ...
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### How to determine whether a threaded rod will rotate under load

A part of a structure I am designing incorporates a large threaded rod (1") diameter mounted vertically both for structural strength and for the potential to adjust the height of the top mounted ...
40 views

### Frames and Statics Question

this is an image describing an exam question I have to practice on, and I am so stuck.
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1 vote
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### Nuclear weapon doubts

Sorry I am not an Engineering professional or student. But I had a question regarding US Nuclear weapons. Specifically, is it possible that Nuclear weapons we created in the 50s still work? The major ...
35 views

### Will the COP of 10 stage cascaded refrigeration / AC system be high?

Consider a cascaded refrigeration/AC system that has ten stages, with each stage cooling by only 5°C/9°F. For example: Cooling takes place from 40°C to -10°C over ten stages. Each stage has a high ...
46 views

### Bolt tensile load through an "intermediary"?

Following up on this question, does it change anything if the bolted arm is an intermediate arm (e.g. some sort of mating interface like below)? That is, the arm receiving the load is connected to the ...
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### Would there be a flame front in this case of combustion

Suppose a piston enclosing an amount of air-fuel mixture and then this piston compresses the mixture to the point of auto ignition, if every part of the mixture ignite simultaneously is it safe to say ...
14 views

### Plumbing - Existing Building Water Fixtures Supply Units and Operational Demand

If you have an existing building that is several stories, I would like to know the best way for assessing the water supply fixture units demand. If you upfit one of the floors, the new fixture demand ...
40 views

### Can I use water flow meter for measuring flow of glycol accurately. Why yes/no?

I have water flow meter and I was wandering if i could reuse it in new project for glycol.
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### How to check if the tubing of a portable split air conditioner is twisted

Last year I bought this portable split air conditioner, Trotec PAC 4600. The people who delivered it made an awful mess: they put it upside down in the box(!). Unfortunately I did not know that, they ...
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75 views

### Building Equations of Motion

The following figures represent a model of a building, can someone help me, extract the newton equations of motion and determine the degrees of freedom.
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### Motivation behind contraints on virtual displacements

Consider a body with displacement $(u,v,w)$, where $w$ is assumed to satisfy $w=w(x,y)$ (that is, the vertical displacement does not vary along the $z$ axis). Why exactly should the virtual ...
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### NPT pipe thread. $L_3$ vs. $L_2-L_1$

The standard "ASME B1.20.1 Pipe threads, general purpose", NPT thread section includes these two lengths: $L_3$ = length of thread beyond $L_1$ (which is the length of hand-tight engagement ...
81 views

### Failing engine A-Mount (bad design by the automotive manufacturer?)

I currently own a Tata Nexon Petrol car (in India) where I have seen (on facebook, Telegram, WhatsApp owner groups and youtube) that the A-Mount on the engine has suffered multiple failures for some ...
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103 views

### How is flow energy different from kinetic energy of a flowing fluid in a control volume?

While I am studying about Mass and Energy analysis in Control volumes in Cengel and Boles I came a across a term called flow energy. The textbook definition that was given is as follows - "The ...
319 views

What is the meaning of L2 = "Length of Effective Thread" for NPT threads, mentioned in standard "ASME B1.20.1 Pipe threads, general purpose"? Note: the standard includes formula L2 ...
29 views

### Magnitude of F given the u component magnitude and 2 angles

My task is to determine the magnitude of F. My guess is that there is some obscure concept that I have yet to learn from class to solve for F, but at the time of me posting this, I do not know what ...
20 views

### Drone Geometrical Shape

Drone Can Drones be designed with geometrical shapes viz Kite, Cylinder, Sphere etc?
49 views

### Material suited for fixing leakage in liquid nitrogen dewar

I need to fix a leak on the inside of a liquid nitrogen dewar which acts as the coolant tank for a spectroscopy CCD camera. Due to the design of the camera, I unfortunately can only access the inside ...
54 views

### Viability of bladeless wind power generation

I have recently thought of two designs for bladeless wind power generation; And They both essentially ionizes the incoming wind which then passes through a coil, the flow of charged wind particles ...
78 views

### If I'm making an engineering drawing for a machinist, how do I define the undercut of a gear?

The drawing is of a small gear with an involute curve turning into a trochoid root causing an undercut. How do I define the undercut of this gear for a machinist?
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### Atomic weapon design book [closed]

I’m starting my degree in nuclear engineering in September and was wondering if anyone knew any good books for Atomic Weapon design please?