# 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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59 views

### Pumping machine (Centrifugal ) fails to pump

I have a centrifugal pumping machine that fails to pump up consistently. When powdered on, it spills up water, then stops and continues intermittently like that without a consistent flow of water out. ...
1 vote
394 views

### Calculating mass flow rate of a scramjet engine?

First post here. I'm an undergraduate ME interested in fluid mechanics. I came across scramjets and I was interested about the engine. I want to calculate the mass flow rate of the engine and I made ...
37 views

### How to make Peaucellier–Lipkin linkage work?

I tried in math.stackexchange.com and they send me here. First: Don't crucify me for not "doing math", or asking a dumb question. School was a long time ago, and lose what you don't use. My ...
297 views

### Can a compressor give the same discharge pressure even if suction pressure varies?

The task is to maintain compressor discharge pressure at 200 bars. The inlet pressure varies with time from 200 bars to 10 bars (emptying a compressed air tank and compressing to transfer it to ...
57 views

### Did anyone ever make training wheels for the original Segway personal transporter device?

I am curious to know if Segway, or any other company, has ever made front and rear training wheels for the original version of the Segway personal transporter device. To help illustrate what I mean by ...
186 views

### How to attach a metal rod to an air cylinder?

I have signed up for an engineering class, and the first project is purely mechanical. I've never done mechanical work, so this is quite interesting to me. I have come up with the following project - ...
585 views

### How can a non flowing fluid have kinetic energy?

I am currently studying engineering thermodynamics from Cengel and Boles and there it is given that total energy of non flowing fluid per unit mass basis is given as $e=u+\frac{v^2}{2}+gz$.But if the ...
144 views

### Net force exerted by spring

I want to find the exact net force exerted by the spring between pt. P and C, when it is compressed till point P with some mass, m attached to it and released (assuming spring goes to pt. C after its ...
1 vote
109 views

### Static discharge inside a fuel tank

I am trying to build a sort of paramotor powered by hydrogen, my rough design looks like this; First dilute sulfuric acid is electrolyzed in a sealed aluminium container. Second, the valve is ...
47 views

### What is the name for a design element which includes trusses within a member?

I cannot think of what to call this design technique, where a truss-like structure is used within a member to provide strength and rigidity with minimized weight. I’ve included a picture which ...
1 vote
318 views

### Clock pendulum period vs driving weight

I've got a weight-driven pendulum clock, I increased the driving weight by 10% and the period decreased by 1%. Why? What's the equation? The pendulum is length = 32cm; bob weight = 7g; rod weight = 7g....
72 views

### How to work out the kWh required to compress hydrogen gas?

I am trying to work out the kWh/kg of compression of hydrogen. I have used the isentropic compression calculations and get values for the entropy but am unsure how to get this to a kWh value. I might ...
40 views

### Question about scaled models of compressors and turbines

Hello I am an engineering student and I have some questions about scaled models for compressors and turbines: When building scaled models of compressors or turbines to analysis them, what ...
1 vote
48 views

### How to calculate the torque disturbance of an unbalanced flywheel?

I would like to understand how an unbalance of a flywheel affects the dynamics of a simplified mechanical model. Assuming that the mechaincal dynamics can be modeled as (neclecting inertia of the ...
26 views

### Searching for geometric modeller to investigate behaviour of beam when deflected

I have the scenario where I wish to model the movement of a simply supported beam under a central point load. I've done some stuff in R Studio to come up with deflection plots and that's fine. In ...
136 views

### Making a three phase squirrel cage induction motor in PLECS?

I was just curious if I was to make a Three phase squirrel cage induction motor connected to a mechanical load System Block Diagram in PLECS with a rated frequency of 60hz, 6 poles, 220V rated stator ...
1 vote
3k views

### Tolerances in a pin-hole assembly

Hi guys, can someone explain how to do this question? This question is under Geometric Dimensioning and Tolerances and I am clueless on how to tackle problem like this. EDIT This is the explanation ...
110 views

### How do you calculate the chain tension required when compressing bulk material over a conveyor?

Bulk material is conveyed over a slat conveyor, and the material is leveled with overhead rollers while being transported in the conveyor to maintain an even material height. Most of these "levelers" ...
1 vote
112 views

### Are there is vanadium-free high speed steels?

Vanadium is present in all high speed steel grades. Unfortunately vanadium is not only very expensive but is also a well known cytotoxic metal. Some workers get a severe persistent cough lasting for ...
53 views

### Activate a mechanical end-stop with a lever

I would like to be able to record the motion of the shafts on a loom. I have some mechanical end-stops, and would like to trigger them with levers that raise and lower when the treadles at the base of ...
2k views

### Calculate the required torque of a motor

I want to know how much torque I need for my engine. Imagine a wheel with a motor in the center. One like this: Let's say the wheel measures 400mm, weighs 10KG, what is the formula to make that ...
108 views

### Passive mechanical element that can act as counterforce for a spring

An elavator is a moving cabin that gravity acts on. On the scales of the typical elevator application (a skyscraper for example), gravity is constant. So the gravitational force can be counteracted by ...
29 views

### DLC wear resistance

I read that a thickness of one micrometer of DLC coating (which, if I understood correctly, shows similar properties to diamond), increases the lifespan of an item plated with it from a week to more ...
1 vote
84 views

### Are there any advantages of using BEM for contact problem over FEM, apart from lesser computational cost?

FEM - Finite Element Method BEM - Boundary Element Method If we had access to "enough" computational resources (to discretize the entire volume domain in FEM to the same degree of fineness, ...
16 views

### I have a question about INISTATE Code (Analyzing a curved plate)

I'm studying welding-induced residual stresses for curved steel plates. So, I need to use the INISTATE code taking initial stresses. This is the picture that I want to analyze. I divided a curved ...
1 vote
197 views

### What is the type of hinge used in fold-down car tv's?

I am trying to find out what type of hinge or mechanism is used in fold down car TV's. I need to buy one for a project I'm working on but dont know the name. See picture above.
169 views

### The behavior of the stress-strain curve of metal, containing a void

Let's assume that in a metal sample without any dislocation, there is a void. Then we conduct a uniaxial tensile test.
231 views

### Need help with converting rotary to linear reciprocating

First of all, not an engineer. Clueless to proper lingo or terminology. Project. Looking to create a compact, pen like device by using a 12v dc motor to create a reciprocating motion. Kind of similar ...
194 views

### How to calculate traction force w.r.t. rotational speed of a shaft mounted at a certain angle on a surface?

I am designing a new mobile robot platform and i need a generic solution for the robot in order to establish a proper mathematical modeling. My question is about calculation of the traction force of ...
12 views

### High temperature in seal oil vacuum pump (not in the bearing), steam power plant. Why the seal oil vacuum pump suddenly increased in temperature?

Seal oil vacuum pump in steam power plant, suddenly have temperature increased, it's in the pump's body, not in the bearing. Why is that happen? I noticed that temperature of main seal oil tank in ...
1 vote
62 views

### Ideas for running 2 gas engines to 1 shaft with pulleys

First time posting, but love the forum. Hopefully this hasn't been asked before. I could only find the question in relation to electric, not gas engines. I own a pressure washing business, and my ...
92 views

### Estimating yaw torque and power of HAWTs

I am trying to estimate the amount of torque and power required to rotate a 3 bladed Horizontal Axis Wind Turbine (HAWT) about a vertical axis("yaw" motion). I would like to estimate the ...
13 views

### What does the resonance frequency mean in inertia matching

Like Kollmorgen shows in this PDF how you can calculate the resonance frequency of a motor coupled to a load. But with what can I Compare this frequency? It is clear that a higher resonance frequency ...
44 views

### Could a miniaturised, lightweight Direct Air Capture (DAC) capability for CO2 be incorporated into industrial air conditioning units?

Rather than focus on the daunting task of upscaling demonstration plants on the lines of Climeworks to the extent necessary to remove the gigatonnes of CO2 scientists deem necessary should we not ...
219 views

### Is it possible to seal a perfectly smooth surface?

I've heard that a surface roughness needs to be within a defined range, but in theory, is it possible to seal a perfectly smooth surface? E.g. with an o-ring, static or dynamic? Intuition tells me ...
196 views

### What is the name of this piece in the image attached?

What is the shiny metal piece around the tube in the picture called?
126 views

### How to compute the size of a polygon moving along non-circular guide rails

I am trying to compute the optimal (a non-optimal solution would also work) size of carts that can move along guiding rails. Each cart is connected to the rails at two points. Each cart is also ...
23 views

### Nuclear pulsejet

As the title suggests, I am wondering about the feasibility of Nuclear powered pulsejet engines, including Radioisotope Thermoelectric Generators (RTGs). I am not talking about Nuclear pulse rockets, ...
277 views

### Push / Pull Steering on an axle

I have a base with 4 wheels, the rear axle is a motor which drives the base forward or backwards, this contains a diff, so there's no problem there. The front axle is a steering axle like that in a ...
1 vote
188 views

### Reacting Propeller Torque?

A motor is used to drive a shaft that is geared through 1:1 bevel gears to a propeller. The shafts are mounted on bearings in a hard casing that is attached to a 2nd ground. I want to know if the 2nd ...
1 vote
19 views

### -AN Fitting Compatibility

I have a -6 AN fitting on the end of a hose. I am not familiar with AN fittings and I don't understand how to interpret the table at the bottom of the Wikipedia page on this subject. Does this table ...
311 views

### Modeling rigid body dynamics: Trouble with equations, encountering nonsense answers

Hi, I am working on modeling a simple rigid body dynamic system through a certain range of motion. Here is the picture of the system. I am trying to solve the system for the variables \$x_1'', y_1'', ...
235 views

### What does a higher eject force do in a clutch?

I am looking at two clutches and the details on both are identical. The only difference is the eject force. One is 3300 and one is 3600. Does a higher eject force mean higher performance? And also ...
87 views

### Can I drive a pulley with two shaded pole motors using one motor at a time with different size pulleys for speed control?

Using two same RPM shaded pole motors, one with a one inch diameter motor and one with a two inch diameter. Using a DTDP switch to swap power from one pulley to the other. For a two speed rotation ...
259 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 (...
186 views

### What are rules of thumb for designing a gravity feed system for cylinders?

So, I just printed out this battery holder off Thingaverse. Unfortunately, it doesn't work very well, so I'm interested in redesigning it. There's a number of issues but the most annoying one is ...
1 vote
765 views

### Is there a formula that relates the two angles in a crank rocker?

I'm working on a mechanism that requires a crank rocker - is there a formula that relates the angle (to some fixed reference; horizontal, vertical, whatever) of the driving "crank" to the ...
96 views

### Need help analyzing torque transfer and slippage condition between parts

I have a scenario where Plate A (light blue) shown in the image below is being pressed against two different plates that are in contact with different sections of Plate A. I would like to know which ...