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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17 views

Indian Ink was available during 1980s but not available now [closed]

Does anyone has the idea about Indian Ink ? Now a days all drawings are being made on computers. So high risk is that your design is being copied by the hackers. I want to go back to the 1980 ...
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3answers
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Is a ship a statically indeterminate structure?

We can consider that a ship is a complex implementation of forces on a beam, that a ship is essentially a beam. The support is the buoyancy force which is continuous but it takes different values ...
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How do mobile phones produce signals?

Normally it would require alternating currents to product electromagnetic waves. Yet as mobile phone is powered by batteries which only produces direct current, what type of mechanism/structure allows ...
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1answer
41 views

Is G-code used also in NC or just in CNC machines?

I am trying to really understand the difference between NC and CNC machines (not just to see the "old dark-green display" to know that it is an NC machine). On the web people are saying that ...
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1answer
47 views

Identify this textbook

I would really like to buy this textbook, but only see a scan of one chapter online. Could anybody help me identify the book? Thanks!
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2answers
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Designing a progressive die to make a blank on a thick steel sheet

Suggest and Design a progressive die to make a blank with a 2 mm thick steel sheet as shown in Fig. The ultimate shear strength of the material is 480 MPa. Calculate press capacity assuming 75% ...
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1answer
68 views

What is the maximum distance for eavesdropping? [closed]

There is a closed question https://physics.stackexchange.com/questions/276667/what-is-the-maximum-distance-for-eavesdropping-sound-waves on Physics Stack Exchange and I thought this might fit better ...
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1answer
29 views

Impact damage in composite materials

I want to do a test where I use composite materials to mimic impact damage on aircraft materials such as impact from hailstone while the aircraft is in flight. I will cut out specimen sheets using a ...
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4answers
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Why does "potential energy" have the word "potential" in it?

Imagine a block of mass $m$ placed on the ground. I slowly lift it up to height $h$. The work done by me on the block is $mgh$. This amount of energy is now stored in the block when it is at height $h$...
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Sprocket/wheel Configuration for most efficient drive on a straight caterpillar track

I’m rewording this question so people can better understand it. On a “caterpillar track” built on a straight line, with 1 or more sprockets driving the vehicle with motors in direct drive. 1.) How ...
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1answer
46 views

What is this 2 DoF joint called?

I'm looking for the common name(s) or other unique information of a 2 DoF pendulum joint that has one rod that pivots about one axis, connected to a fork that pivots about the orthogonal axis, which ...
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1answer
48 views

How much longer could Titanic have remained afloat if it had gotten rid of its anchor and chain right after hitting the iceberg?

I am wondering how much longer the RMS Titanic could have remained afloat if the crew had allowed the ship's anchor and anchor chain to fall to the bottom of the ocean immediately after the ship had ...
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Sheet Metal Panel Install on Roof

I work as a Design Engineer for an industrial ventilation company. In order to complete our outlet for our ventilaion system, we need to install a 54" by 40" steel panel (16 gauge mild steel)...
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1answer
32 views

How do I calculate the total force required for a linear actuator? [closed]

How do I calculate the total forcerequired for a linear actuator? The image enclosed shows a series of door panels, each with a cam that i would like to connect to a linear actuator on the right hand ...
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1answer
46 views

What is a minimum deflection rating for a spring?

I'm looking at trying to use some springs to isolate percussive noise* traveling between closed rooms from a walking treadmill in an office environment. I found the following website (below) for ...
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1answer
34 views

Compressor + engine

G´Day, Something got me thinking and I want to know if anyone else things this is possible. I wonder if you can buy a electric air compressor, Connect it to your car/truck Battery, and connect the ...
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Euler angles from angular velocity pseudovector

According to wikipedia page https://en.wikipedia.org/wiki/Angular_velocity Euler proved that the projections of the angular velocity pseudovector on each of these three axes is the derivative of its ...
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1answer
29 views

What is a shaft collar called that is used to restrain a pulley?

I would like to look for a shaft collar like the one used in this photo of a cable robot: As you can see, there is a flexure that clamps the collar onto the shaft (as a shaft collar does). In ...
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2answers
33 views

Control System Response

How does one find the zeta value or the frequency of an over damped response curve. I am used to determining things by using the log-decrement equation. Does that apply here even though there is no ...
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1answer
43 views

Bearing stress in Bolts

Consider the arrangement shown below. It consists of a bolt, clevis and plate. Since, the clevis and the plate press against the bolt, the bolt will be acted upon by forces 1,2,3 (as shown). There is ...
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1answer
34 views

How do I properly scale down a force for scale-down model testing?

I am designing structural frame for a shipping container that would have 8000 lbs of weight stacked on top of it. Of course, i don't access to real size container. I have built a model whose scale is ...
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3answers
84 views

Is there a simple trigonometric relationship between these two angles?

The setup shows 3 rigid links (with fixed lengths) constrained by 4 joints. The blue joints are fixed in place and only allow rotation, while the black joints can move and also allow rotation. ...
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1answer
44 views

Drawing nyquist diagram by hand for a system with time delay

how can I draw the Nyquist diagram of Kexp(-Ts)/(s*(s^2+s+a) by hand for different a and K values and examine the stability of the system depending on T value? I drew for the case with no time delay ...
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2answers
54 views

Can stainless steel be used in continuous high temperature environment (500°C to 850°C)

Can i use stainless steel as a furnace roof. Furnace temperature will be max upto 850°C. If so which ss grade will be the best in this situation. Thanks
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Examples of two dimensional heat conduction problems

Can anyone give me some examples from real life, where the heat transfer can be modelled as two dimensional. Also if one could explain why we can model it as 2 dimensional.
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1answer
24 views

Workbench: Explain the difference between the case with bonded contact and the case with the frictional coefficient of 0.01

Explain the difference between the case 1 with bonded contact (top image) and the case 2 (bottom image) with the frictional coefficient of 0.01 For both cases, the top plate has displacement and the ...
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1answer
54 views

Please accept my request for an obsolete engineering theory [closed]

I am writing a thesis concerning government organization, and I would like to make the analogy that illustrates that law scholars are failing to seek practical solutions, because they are confined to ...
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1answer
59 views

Controls System experiment

We performed an experiment in which we turned a bicycle on its side and placed a piece of green tap on one of the spokes. We spun the wheel and recorded the wheel spinning until it came to a complete ...
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1answer
32 views

Determining elastic limit for a nonlinearly elastic material, to be used for calculating chord modulus (i.e. Young's modulus) in tensile testing

I have a protein material that is nonlinearly elastic; from the get-go, the stress-strain curve shows quite an immediate curvature. I have to use chord modulus (reference to ASTM E11-04). The problem! ...
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3answers
208 views

Equivalent viscous damper for friction damping

I have a friction damping system which is exited by a harmonic force FE (depicted on the left side). Is there a way to convert the friction damper to a linear or nonlinear damper, such that the ...
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1answer
32 views

Force Transmitted to the support (Vibrations)

Consider the spring mass dashpot system shown below which is acted upon by a harmonic excitation force F(t). The reference is taken at the equilibrium position of the system when no F(t) was present. ...
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4answers
105 views

How can you make a solid box jump up with no external forces?

Let's say I have a box lying on a flat surface. Inside the box, I make a heavy mass hang from a spring attached to the top of the box. If we pull the mass all the way down and let it go, I believe it ...
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1answer
56 views

Type of Engineer [closed]

I am a mechanical engineer by education (master's degree). I have been working for 6 years in industry. However, I am beginning to search for a new job. I work at NASA as an instrumentation engineer. ...
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2answers
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What is the reason for forbidding liquids for cooling in drilling on cfrp/Al or cfrp/Ti stacks?

I recently did some research on the effect of cooling on CFRP/Al7075 drilling.But I read somewhere that liquids are forbidden for cooling operations on these multi layer plates !!! , And I wanted to ...
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2answers
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Homogeneous materials and direction dependence of properties

A homogeneous material is a material which has a uniform composition throughout. What do we mean when we say "uniform composition"? I have learnt about pure substances in Thermodynamics ...
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2answers
40 views

What is the best time interval in condition monitoring programs for checking rolling bearings?

The time intervals between observing or measuring the vibration of rolling bearings in industrial plants are so important in condition monitoring programs. For instance, some experts measure the ...
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2answers
67 views

A problem with quantifying ductility of a material

The textbooks I'm referring to for studying strength of materials say that we can quantify ductility using percentage elongation or percentage reduction in area up to failure point. The higher the ...
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1answer
38 views

Why not put an air compressor on an exhaust to store co2? [closed]

For short-distance drives in a car, why not put an air compressor to store the co2 and dispose of later?
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Pv Diagram of a pressure cooker

For a bit of self training in thermodynamics, I've been trying to think of some random systems and go ahead and try to solve them, some of these things I've stolen from random googling of university ...
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1answer
36 views

Automated Opening and Closing of hinge

I am trying to design a mechanism that puts tension on a string. The purpose is to dip this string in a solution for a stipulated amount of time, and once the time is up, the string is pulled back up! ...
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3answers
37 views

Difference between fast or slow rising force on materials' breaking strength

Assume that force is applied to a material like a rope, steel cable or a beam until it tears apart. Does it make any difference for the breaking point if the force rises slowly or really fast?
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5answers
927 views

Mechanical mechanism that regulates gear's rotational velocity

Please do note that I am a civil engineer not a mechanical engineer. I have a gear that rotates at a speed that varies with time. Usually, it rotates at speeds higher than the desired speed. Is there ...
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3answers
50 views

How to convert car power into energy (MJ) used per km?

I am currently attempting to do an energy audit regarding how much energy my car uses per kilometer. I am not sure whether my approach to this is right, and it feels like I have made too many ...
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6answers
2k views

How to work on big CAD project in team?

I'm always confused on what is the effective way to work on CAD with multiple team members to make it efficient. So far, as I'm freshly graduated I only work on a project where I'm the only one using ...
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2answers
46 views

What happens when we remove the load, in different regions of the stress strain diagram of mild steel?

A: Proportional limit| B: Elastic limit| C: Upper YP | D: Lower YP Let us say, the gage length was 100mm (random, just for the sake of understanding). I know that if I unload the body anywhere between ...
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5answers
72 views

How can I add the torque of multiple gears?

If I have 3 gears meshed with a gear in the center of the 3 gears as shown in the picture. all of those 3 gears are connected to different power sources. They are free to rotate in the same direction ...
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0answers
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Confusion between Steady flow and Space-Time invariant density field

Let's take the example of a steady flow with velocity field as $u=βr(\tilde{r})$. Now, we can find a density field $ρ(r,t)$ that satisfies the mass conservation equation of $∂ρ/∂t+∇(ρu)=0$. First, ...
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What happens from B to C in this stress strain diagram of mild steel?

Image Source: https://mechtics.com/design/strength-of-material/stress-strain-curve-for-mild-steel-with-defination-of-stress-and-strain/ I know that A is the proportional limit, B is the elastic limit. ...
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2answers
86 views

Could the St. Louis Gateway Arch be used as a support structure for a giant vertical axis wind turbine?

I am curious to know if the St. Louis Gateway Arch would be strong enough to act as a support structure for a giant vertical axis wind turbine. I way I am envisioning this being constructed is that a ...
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5answers
5k views

Why are screw holes in most of the door hinges in zigzag orientation?

What advantage does it provide? Explaining with a figure would be helpful. I tried to draw a free body diagram and equated the sum of force and moments to zero, but still was not able to find out.

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