# 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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78 views

### compression buckling under lateral load

I'm trying to figure out what size of round tube to use for a tensegrity structure that'll probably have people climbing on it. The rigid elements are 21' steel tubes, and in normal cases they ...
309 views

### How can I measure the coefficients of friction of pulleys?

I have to study several industrial pulleys made for lifting heavy weights. It is important to select one which has a low coefficient of friction because the system is based in a hoist and several ...
177 views

### How fast can Jansen's linkage driven walker go?

I've seen videos of Theo Jansen's linkage driven walkers, and they all walk really slowly. Is it because they want to showcase leg movement or these things actually can't move fast?
199 views

### Why aren't modern pistons circular?

I'm trying to make most of an engine from scratch (cylinder, crank case, piston). I've been reading about pistons and I've learned that many modern pistons are cam ground--slightly elliptical in shape ...
38 views

### The Hydrolock - How to build a deep sea docking system?

How do you build a docking system at deep sea pressures? Example a Challenger Deep Sea Base at 10,000 meters seawater or approximately 1,000 atmospheres? My answer below is meant to be a logic-model, ...
143 views

### Head loss for T junction diverging water pipes

I am writing to ask for help with a T-junction pipe problem. Attached picture shows the pipe configuration. The schematic shows a large pipe with ID 16.5mm and smaller 4mm ID tubes connected to it. ...
148 views

### Velocity inlet boundary condition in Ansys Fluent

Ansys Fluent offers a very simplified version of boundary conditions. So if I know the velocity at the inlet, I need not care about pressure and vice versa. What I am having trouble with is that I ...
46 views

### Rajay 300B Compressor Map

Question about the 40K speed line. What is happening when it drops off to the right? It starts around 60 CFM 1.2 pressure ratio and then drops to 1.0 pressure ratio at around 250 CFM. Are they ...
50 views

### Does the torque on gear varies with different gear arrangements?

Suppose that there is a gearbox with gear ratio 3000:3. The gear with 3000 rpm will have a smaller torque than the 3 rpm gear. My question is that will for different gear arrangement(i.e planetary ...
43 views

### Not too sure how to approach this equation - fluids mechanics

Apologies if anything has been left out. Ok, so there is just 1 equation which I am struggling to understand, I have made an attempt and also written out the full equation in 2 parts, but I dont know ...
33 views

### How to connect the rings to the coil

Hello I was recently watching this video and I have 1 question the video doesn't explains.It says that when the coil will start rotating the rings will start rotating as well. But how do I connect ...
54 views

### Length of semi major axis for the ellipse in “Total Strain Energy theory”

The equation describing the "Total Strain Energy Theory" (Haigh & Beltrami's Theory of failure) is given as follows: $$σ_1 + σ_2 - 2μ σ_1 σ_2 ≤ (Syt)^2$$ where $σ_1$ and $σ_2$ are ...
51 views

### How to calculate riser dimensions given cast material and cast dimensions?

I tried to calculate the dimensions of a cylindrical riser with height and diameter being the same ,for casting a steel cube,I tried using both Caine's and modulus method to solve it ,but every ...
30 views

### Can we coat brass with nickel by peen (mechanical) plating?

Is it possible to plate brass conductor with aluminum by peen plating?
43 views

### Stress Analysis University Report Help

I'm working on a final report for the mechanics of material course, and the project was to choose a structure or mechanical element and carry out stress analysis using solidworks and then confirm ...
125 views

### How would you go about calculating the force required for an actuator to lift a bridge?

I have been trying to come up with the optimal way to calculate the force required for an actuator to be able to lift a bridge 90 degrees. (A drawbridge) The actuator is placed as follows: (The bridge ...
35 views

### Please check the front,top and left hand side view of my figure

Below is the link what I have tried Please check if it is correct or not?
38 views

### Method of joints not working on simple truss, supposed to be stable and determinant

In the process of editing the question to put better pictures of my dimensions in, I realized that how I calculated my angles was incorrect, and that is why my answers were yielding inconsistent ...
38 views

### how to determine how much speed a motor will produce under load?

I am working on a one-wheel project, I would like to use an electric go kart motor chain driven to a 30 cm diameter wheel and get 90 kg at least 13 m/s with an acceleration of 3 m/s2, I ...
45 views

### How to Calculate Torque to Prevent Rotating

I'm stuck with how to calculate the external torque which must be applied to prevent the aircraft rotating about axis? The imagine shows an aircraft which has a jet engine with a rotor that has an ...
24 views

### How a turbo jet engine produces thrust

As i read on some website of nasa, that velocity of the gas flowing from nozzle of the jet is responsible for thrust, But ky confusion is that, as the velocity increases presure should drop at nozzle, ...
47 views

### Design suggestions for Mechanical rotating disc with 30 degrees step

I am a software engineer with no knowledge of mechanical engineering. I need to buy or build a rotating disc which can rotate in 30 degree steps only i.e each time I try to rotate it, it should take ...
30 views

### SINGLE supported beam

Let's say I have a beam supported exactly in the middle (like a seesaw) and a distributed force applied on it across the beam. What is the way to calculate the displacement, moment, shear...etc of the ...
43 views

### understanding required torque for a servo

Good morning. I have been reading the threads about "Understanding required torque for a motor lifting a weight" in hopes it would apply to my situation. I would like to utilize an R/C servo to rotate ...
37 views

### Does utilizing exhaust energy to supercharge (“turbocharging”) increase the thermal efficiency of a gasoline internal combustion engine?

The work done by a turbocharger increases the inlet charge without much of a burden to the exhaust flow. This increases the amount of air (and fuel) that flows into the engine. How does this affect ...
64 views

### Device with no moving parts to increase fluid pressure?

I'm currently designing an air rifle and am looking for ways to increase projectile velocity without resorting to combustion, modifying the projectile, barrel length or changing max pressure within ...
109 views

### Why are rotary ramjets not replacing turbojets yet?

Rotary ramjet is an engine that uses ramjets attached to a shaft to allow them to operate at the supersonic speeds they require without the engine itself being in translational motion. The huge ...
55 views

### calculate number of cylinders and volume in a turboprop

I've been given the following: CL (lift coefficient) $\eta_p$ (efficiency of the propeller) $n_p$ (number of revolutions of the propeller) $n_e$ (number of revolutions of the engine) $\eta_g$ (...
88 views

### Impact capacity of tension cables, columns and foundations

A rock is falling from an embankment of mass $m_a$ at a height of $h$. Below, a fall protection fence catches the rock, dissipating the energy through tension cables to steel posts and then into ...
52 views

### What is the Thickness of JIS Standard Pipe

I work in engineering company that doing pipe installation. Just now our company got inquiry from Japanese company. They ask me to manufacture a pipe for exhaust ducting. The thing is they use ...
71 views

### Change of fluid of Pump

If the fluid moved by a pump is changed by another different one, what will be the effect of such kind of operation for the pump ? Specifically, a pump moving 60 m3/hr of "liquid nr. 1" (sp.grav.: 0....
51 views

### How far can we compress air manually?

I am not sure if such devices even exist, but I'm sure we can improvise. A device in which we could (manually) turn a shaft, screw a screw, or hammer an air-tight follower into a strong walled ...
2k views

### What is the tolerance of True Position without Datum Callout

I have a drawing that has true position called out on many many holes. However, there are several holes that have true position (boxed dimensions)called out but no datum reference or control box. ...
51 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 $$I_{xx} = \int\int yy \text{ }dxdy$$...
44 views

### Thrust by turbo fan jet engine

How much thrust can I produce with a turbofan jet engine without injection of fuel and with just compression of air, which will be heated by convection if initial temperature of air of 20 oC and its ...
40 views

### Public data re possible estimate of baghouse efficiency. Plus characteristics of chromium emissions. Thanks!

I'm doing an article on a company whose Title V Operating Permit is currently under review by state regulators. (See biographical note below.) See also my specific questions, numbered below. Most ...
11 views

### What is the role of the cooler in the cooling system?

It would be helpful if you could give the working schematic diagram of the cooler.