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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10 views

A Variable Valve Timing (VVT) engine with exhaust GT added, with and without Turbo Charger applied to the crankshaft?

This topic is the follow-up to the original topic: Why are turbo compound engines not more widely used? Why are turbo compound engines not more widely used? Please, do understand that I am a pure ...
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Inertial Torque Exerted By Engine on Crankshaft

In Shigley(5th Edition), in Chapter 14. Dynamics of Reciprocating Engine ,Section 14.7 Inertia Forces, the inertia torque exerted by the engine on the crankshaft is given as $$ \mathbf{T}_{21}^{\...
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How do I compute the torque in ft lbs to turn a screw and move a 2000 lb weight?

I am having trouble locating the calculations for finding the torque, in ft/lbs, required to turn a 1/2" screw with 13 threads per inch and pull 2000lbs 6 inches. .
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Database for stiffness matrix?

I have searched everywhere for the stiffness matrix of GFRP, but there isn't a single paper or site that experimented the full matrix. Is there any sort of database for the stiffness matrix of many ...
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36 views

Adding the effects of two rods to move a single rod

I have to deal with a situation where I have two parallel and completely independent rods whose motion is dependent only on external inputs, and I want to add up the lengths traveled by each rod. My ...
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Cylinder - surface contact and deformation

I'm trying to calculate the vertical movement (delta) of the center of a deformable cylinder in contact with a non-deformable surface. The problem is presented in the picture below. The problem is ...
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11 views

Estimating static electricity on aircraft

I am looking to design and size some static dischargers to be placed on a new aircraft. The main questions I would like to answer are: Is there any data for true airspeed-prevailing conditions (...
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1answer
41 views

Pullout Force of Screw from Epoxy

I would like to estimate the pullout force required to pull a screw out of epoxy. Mine is an unusual situation where I want the joint to fail to protect other parts of the assembly; that is, it is a ...
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44 views

Continous Gear Shifter

Is there any gearing system that would allow one to make the torque ratio as precise as they wish? Bicycle gears have discrete ratios, and also have some annoying slippage when the chain falls onto ...
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32 views

Latch design for home exercise equipment

I have a latch design problem and need your help - many years in software engineering aren't helping me much here! Two pieces of 60x30mm RHS become parallel/adjacent (on the 60mm face), with a 5mm gap,...
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21 views

the amount of the k (constant spring) in torsion spring [closed]

I am looking for the amount of the spring constant in torsion spring. I have a little torsion spring used in a two-hole paper punch with the specifications written below, and I need to know the $k$ of ...
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Testing of water filtration device (and membranes removal characteristics)

I am doing my final year project as an undergraduate and am designing a brackish water filtration device that uses nanofiltration membranes. I wanted to know if there is any suggestions on how I could ...
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Where can I learn about continious elongation mechanism of a strip? [closed]

I've been working on a project where a tension leveler is involved. Under which subject can I learn more about elongation of a strip at a continious line?
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What is the value of reflection coefficient of UV-light at water-steel interface? [closed]

I am looking for the value of the reflection co-efficient of UV led light at water-stainless steel interface. How much UV light reflect when interferes with the water flowing in the Stainless steel ...
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Sequence and parts for attaching a rotaing weed whacker head

I have a weed whacker. The string feeding head was removed to use a tri-blade head instead. I need to reinstall the original head. I do not have details for the parts and their sequence. I do not have ...
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2answers
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RV HVAC and Fridge Freezer on the same coolant loop?

Given the space, weight, and power constraints of an RV it is useful to make as much use as possible out of every component. Is there an engineering reason why a refrigerator / freezer and an air ...
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What is the name of this particular mechanical linear position switch made of perforated spring strip?

I'm writing a few elementary paragraphs about switches and switch technology, and I cannot for the life of me remember what a particular kind is called, to give it an honorable mention. Here is a ...
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3answers
73 views

Replicate stepper motor with gasoline engine

For those unaware of what a DC stepper motor is, it boils down to an electronic motor where the rotation can be precisely controlled, i.e. you can control the rotation of the motor in fractions of a ...
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1answer
32 views

As a rugged and waterproof device, how does gopro dissipate heat?

I am new to designing rugged + waterproof products. I am curious about how to dissipate heat when the electronics are running and the ambient environment is even hotter. It seems like the mode of heat ...
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1answer
17 views

Coplanarity Profile Callout Confusion

From Krulikowski (1997), the callout for several coplanar surfaces using the Profile symbol is done by using two surfaces to establish datum plane A-B and then tolerancing the remaining coplanar ...
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1answer
17 views

Serrated locking part

I need to fixate something at adjustable approximate angles. It doesn't need to have a lot of holding power. So the idea is to have washers/nuts that are serrated, that when closed in together, locks ...
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0answers
23 views

Where does this equation come from for membranes?

I've seen this equation used for membranes many times in papers, where T1 and T2 are principal stress resultants. $$\frac{d(T_1\rho)}{d\rho}=T_2$$ I am not able to find an (understandable) derivation ...
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1answer
35 views

Do drawing dimensions have to start from datum?

When specifying the depth of a cut, should the dimension start from the datum surface or from the surface where the cut will be made? In the example below, a cut of 5mm is made from the surface ...
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Calculating (transient) rate of cycles of practical thermodynamic engines (turbojet, multi-cylinder car engines etc..)

I already asked this on Physics Stackexchange but to no avail. Thought this forum is a better place to ask this. I tried to make a plan for a turbojet engine with my physics knowledge and I'm stumped ...
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1answer
36 views

Choice of Datum Features and Number of Datum Features

Consider a rectangular stock section with a dowel hole and other features of size (FOS) on it. The dowel hole serves to locate the entire part. Should my choice of datum features be what is most ...
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Calculate propeller's thrust & torque coefficient for a quadcopter brushless motor

I'm building a quadcopter and I need to know how to calculate the thrust and torque coefficient, $F = bw^2$ and $T = cw^2$ I need to get the $b$ and $c$ (but don't know how to). I'm using 1045 ...
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Can a riverboat tack upriver?

Note: This question originally appeared on the Physics site (see here) and was closed for being off-topic. Whoops! If ships at sea can tack in a zigzaggy pattern by converting backwards force from the ...
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1answer
35 views

Switching a Circuit on-and-off In-step with the Rotation of a Drive-shaft (Mechanically)

I'm working on a project. The Salient part here is a drive-shaft connected to a bearing, onto which a simple circuit is mounted. I want to switch the circuit on every $π$ and off for the other $π$ of ...
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33 views

Mechanical design estimates with carbon fiber rods

I'm intending to do a little hobby project in robotics. I was thinking about using carbon fiber rods to get a stiff, strong and lightweight design for certain parts instead of my 3D printer. But I ...
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Open bearings in a Schaublin 70?

I would like to clean and change de belt in a Schaublin 70 Lathe, but when removing the main shaft, I noticed this weird bearings: How would I remove it what should I take care about?
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1answer
28 views

Geometric constraints on Planetary Gears

I would like to design a single stage planetary gearbox using standard gears. There appears to be three primary conditions to ensure the geometry of the gears will fit - correct center distance, ...
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1answer
68 views

Fan blower with less airflow in the center

I'm building a ducted fan and I would like it to: have a uniform airflow at the output have good static pressure have a square section output (see figure: air enters the circular edge and exits from ...
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3answers
60 views

Torque required to rotate object around axis using Stepper Motor for Kinetic Machine

Hey all, I'm creating a machine to rotate a socket wrench using an arm attached to a motor shaft in order to make clicking sounds from the object therefore I'm trying to choose an appropriate stepper ...
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Designing a positioner or a lift-column with fine positioning to a target quota and fast retraction

I am developing a system for positioning an object to a variable target quota. I am trying to find a solution that allows a fine positioning to the target quota and then a fast retraction to the home ...
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1answer
43 views

Single shear bolt shear force and moment diagrams

I’m trying to determine what the shear and moment diagrams of a bolt in single shear look like. Before anyone says it, I know that it’s rare that a bolt will ever fail first in bending, and this is ...
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30 views

simulate a temperature in tank

there's a website to size an aquarium heater or chiller. This is just for learning purposes (not for fish) but I have modified these parameters from default to perform a load calculation on a 100 ...
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37 views

UV radiation simulation in ANSYS

I am setting up a simulation in fluent to estimate the UV radiation dosage of an air stream passing through a cylindrical duct with the UV source in line with its main axis. It is a very simple system,...
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2answers
38 views

Where does Second moment of area come from?

Where does the second moment of area come from and how to derive it from scratch, or what is the basic intuition behind it? In other words, what are the origins of $$I_{xx} = \int\int yy \text{ }dxdy$$...
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How to use confidence level in this problem?

The effects of cutting speed (A) [1000 & 1200 rpm], tool geometry (B) [Type i and Type ii] and cutting angle (C) [12-25 degrees] on the life of a in hours of a machine tool is studied each ...
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1answer
15 views

Building an ultralight electric hoist, what gearbox reduction / motor combination for torque / power requirements?

I am building an electric hoist. Design requirements: Lightweight Quiet Relatively low lifting requirements (100 kg) Relatively fast lifting speed (80 fpm -> .4 m/s) Low cost Simple Force ...
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1answer
34 views

What is the meaning of “load case consistent” in stress analysis terms?

I’m a (junior) stress engineer and have been tasked with sizing a lug. Various loadcases have been run through FEM and loads have been distributed into the lug bolt for each. In other words, each ...
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1answer
36 views

How to decrease Nitrogen gas consumption in Iron & Steel Plant? [closed]

I need to decrease nitrogen gas consumption in iron & steel plant. Currently it's not possible to measure every dot from steel mill to determine real usage so they use what air separation unit ...
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1answer
49 views

What causes an inflated spherical cap to look more like a mountain?

I'm working with bulge tests of materials using biaxial loading (applying pressure from one side through a circular aperture). The materials are clamped on the edges. The diameter of the aperture is &...
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25 views

How to weld a copper flange with a Nickel alloy pipe?

I have a copper flange and I want to weld it to a nickel alloy pipe. Normally, which welding technique is used to join these two parts? Also what is the filler material to be used to weld a copper ...
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37 views

Door Design Calculation

I am in process of designing a door; Mass = 370kg Width = 535mm Height = 878mm Thick = 100mm max angle = 120 deg I have done calculations to size the hinges; just struggling with the force ...
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3answers
83 views

Difference between Linear Force and Force about an Axis

I am confused between How forces work when applied in singular linear direction vs Force Applied to a continuous mass about an axis(example to rotate it). Example 1: Consider an object of mass $m$ ...
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2answers
58 views

What is the purpose of those “dual parasols”?

Watching a live video stream from South Korea just now, I noticed these parasols in the background. They look like normal parasols but have two "layers". Like a hole in the top with another &...
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23 views

Are there robotic 'worms' that can burrow in soil and detect metals (e.g. gold), possibly via X-ray?

I looked it up didn't find anything. I was reading about mining and wonder if it's a technology that's used, as I didn't see any mention of it. I suppose the worms would have to be relatively large, ...
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4answers
70 views

Calculate mass needed to balance a UDL lever

I have a lever which is 2m long. The fulcrum is 0.46m from the left hand side of the lever. The lever is has an evenly distributed load with a mass of 10kg. How do I work out the mass needed on the ...
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1answer
59 views

hydraulic Motor/pump minimum speed

I have seen in many data sheets of Hydraulic Gear motor a spec called : "Minimum Speed = 450 RPM" ( 450 is an example) here is a capture from the linked datasheet below : In your experience ...

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