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

Lab Jack with Bi-Dimensional Movement

I just bought a lab jack like this one: Its purpose is to change its height without loosing its rigidity by using the so called: scissors mechanism I was wondering if there is a similar device like ...
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Thermodynamic Steam tables

Having both the pressure and temperature for saturated-water in a particular state of a cycle, I was interested in its enthalpy. When looking at steam tables I am not sure if I should use the pressure ...
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How can I cheaply tilt a 700 lb cactus?

We got some heavy rain last week and a 4.5 ft tall barrel cactus fell over. Assuming most of it is water, it probably weighs about 700 lb. I've read that if I moisten the soil, take care with the ...
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54 views

Is Bernoulli’s equation applicable for systems with pumps?

Please have patience with me as I have not looked at this sort of theory in many years (I am also very new to StackExchange). A question asks the following: A sloping swimming pool two-thirds full of ...
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2answers
67 views

Does thread angle modulate ease of (rotational?) penetration in a screw?

Forgive me if this question is too simple, I'm a complete outsider to the field of engineering and mechanical engineering. A friend of mine had said that the thread angle of a screw modulates how ...
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4answers
112 views

What thickness of steel bar/pipe for home gym?

I would like to build a rack for my home with a pull up bar. I'm leaning towards a steel pipe with a diameter of 42.4 mm, but have no idea how to determine what wall thickness is needed so that the ...
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Gear Terminology [closed]

Can someone please explain to me what are each of the radii that are involved in creating an involute spur gear. There are so many, if you can please explain to me what the difference between each one ...
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1answer
52 views

How to mix pure CO2 with air so that a bioreactor can be fed with air at 0.1% to 10% CO2?

The situation is we have to prepare a gas mix of air and CO2 which has to be given as input from 0.1% to 10% CO2 of air mix to the aqueous medium in a bioreactor? I'm trying to build a simple and ...
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What is a good software for electrical/mechanical engineers that does not exist? [closed]

I have been doing business software and games for over a decade. I advanced my math the past years and feel capable of making an engineering product with a reasonable scope. What would be useful for ...
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1answer
47 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 ...
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1answer
62 views

How can I measure gear efficiency?

I am doing a experiment on various gear combinations and am wondering How I can measure the efficiency (Torque loss) of each gear pair), I have a input shaft connected to the first gear and is also ...
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1answer
23 views

How can I compute minimum thickness for a rigid acrylic panel?

If I have an acrylic (plexiglass) panel, how can I compute how thick it must be to resist bending. So, for example, if I have a sheet that is 24" x 36" and supported by the edges only (such ...
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1answer
53 views

Why the cylinder covers of very big engines are tightened this way?

The engine has 12 cylinders and its power is 104000 HP. Every cylinder has 8 studs M85 which are very slack. I can move them with my hand ( when the nuts are of course not tightened) Also the gasket ...
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2answers
73 views

How to Construct a Primary Auxiliary View given that an oblique surface with 6 sides

I need to construct the auxiliary views with the given front and right side orthographic views. The view is in third angle projection. I observed that there is an oblique surface so that perhaps I ...
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1answer
19 views

Balancing Equation of Octane in combustion Chamber

Hey guys I am trying to balance out the combustion equation for reactants: Octane + Air with products: CO2, H2O, N2, and O2; and 120% oh excess air. My balancing equation looks like this: $$ C_8H_{18} ...
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3answers
114 views

Is there a maximum life for things made out of stainless steel or cast iron?

Do steel objects have a maximum lifespan? I read that "316 stainless steel is estimated to last for 1200 years in a “rule“ environment before heavy pitting. In the marine environment this is ...
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3answers
109 views

I seem to have a fundamental misunderstanding about the double integration method for calculating beam deflection

Here's where I'm struggling So I've tried to find the expression for deflection of a simply supported beam acted on by 4 point loads at varying distances. First I balance out the vertical forces and ...
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Why don't more buildings labels floors with integers? [closed]

Why don't more buildings label floors with integers? This is a lot less confusing than having terms like "ground floor", "lobby", "basement" and whatnot:
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4answers
71 views

Balancing suction air flow at different areas on pipe

I have a T-shaped pipe that is connected to a vacuum pump. Along one side, there are 4 areas of 9 holes where air will get sucked in from the surroundings. It's used to pick up some small objects. The ...
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1answer
44 views

Inconsistant load cell readings - (static) fiction perhaps?

First off I'm not an engineer so please excuse the simple language I use to explain my question! I have an arrangement whereby I have a steel plate suspended from basically a bridge. The plate is free ...
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53 views

Meaning of symbols in a drawing

I recently found a drawing with this symbols. It looks like ome kind of tolerance to me, but I don't know its meaning. What do this symbols mean?
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33 views

Methods to stop jolting in a spring powered projectile launcher

Situation: A machine, similar to an exercise bike which is seen in modern gyms, relies on the input power through pedals via a human. A reduction ratio leads to a mutilated pinon which is used to ...
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0answers
56 views

On rectangular section beam properties of plate stiffeners

I am trying to understand the expression of the vertical dynamic stiffness $K_T$ and the rotational dynamic stiffness $K_r$ which appears in this paper where they consider a semi-infinite plate ...
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2answers
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How do vending machines prevent people from stealing goods?

I never understood mechanically how a vending machine prevents people from accessing goods through the dispensing panel. From what I understand it's not a locked door that unlocks only upon payment, ...
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1answer
68 views

In case of solvation , Who converts gaseous ions to aqueous ? Why do we even have gaseous but not solid ions?

We take Nacl and dissolve it in water. There is formation of $Na^+$ and $Cl^-$ gaseous ions along with 2H+ and $Cl^{2-}$ aqueous ions. Then , Na+ is attracted towards $Cl^{2-}$ and 2H+ is attracted ...
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33 views

Power calculations for starter motor designing [closed]

Let's consider an IC engine standard type motorcycle. What is the power needed from the starter motor to start it's engine? Please make all the calculations by taking suitable assumptions like the ...
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29 views

Brainstorming ways to water seal a submarine with a protruding instrument?

I am currently working on a submarine that has a flat face at one end made of 1/2" acrylic. Currently, there is a 12mm glass sensor that protrudes through a hole in the acrylic face and I am ...
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1answer
77 views

What would you call this mechanism and how can I calculate the forces involved

So I have an assembly with two pins sliding in two groves. First I would like to know if there's a name for this so I can do some more research. Second, if the assembly is standing up so that the top ...
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1answer
65 views

Is a no-moving-parts air pressure transformer possible?

Is it possible to construct a solid state fluid system (tubing, channels, chambers, nozzles, etc.) that can convert the energy from a low-pressure high-flow-rate air current into a high-pressure low-...
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48 views

What is a good approach on creating a custom robotics gearbox

I would like to put together a custom gearbox of the scale of around 50mmx30mmx30mm to fix a gadget that I am designing. My question is how should I approach producing this? Should I design components ...
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Book recommendation for hydrodynamics of bubbles, drops, and particles

I am wondering if someone could please recommend to me some references on the topic of hydrodynamics of bubbles, drops, and particles, preferably in the context of complex and bio fluids. I am ...
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23 views

Cargo box opening system below

I am currently trying to make a delivery drone similar to ones Amazon did. Basically the cargo box which carry the package must open to below in order to drop the package. What I want to do is exactly ...
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31 views

Trapezoidal screw usage on robot arm rods [closed]

I'd like to build toy on picture - uStepper/EEzy robot arm. I'm little bit afraid of plastic gears - backslash, weakness, noise... Do you think trapezoidal screw will perform better when I use them on ...
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2answers
35 views

Assuming identical hole perimeter, for which shape is the stress minimized?

I know that stress is concentrated in the fillets, but what about the average stress along the entire hole? We can choose a circle, an ellipse, or a square with fillets. For which shape would the ...
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1answer
35 views

Need to make brackets for an AC on a truck

I have an old Uhaul that I'm turning into an rv. I'm putting the exterior unit of a ductless mini split AC on the "mother's attic" portion of the truck box directly above the windshield. ...
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Is it possible to Plot Damping Characteristic of a Gas Strut using Universal Tensile Machine(UTM)?

My aim is to use UTM to plot a Force vs Displacement plot which would demonstrate the damping characteristic of the gas strut. There is one existing research related to what I'm trying to achieve ...
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1answer
62 views

Why would anyone “pull the stem out and stop the wristwatch at night or when not wearing it” in the context of mechanical watches?

I read this the other day while discussing mechanical pocket and wrist watches: Plus it is common practice to pull the stem out and stop the wristwatch at night or when not wearing it. You then have ...
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45 views

Strange old smithing machine, what is it purpose?

Is anyone familiar with such thing? I suppose that is something used in forge. I don't have better photos, but "steering wheel" was placed on shaft with small gear and this small gear is ...
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17 views

Is NPSHr dependant on temperature?

I know that net positive suction head available depends on temperature since viscosity, density and vapour pressure depends on temperature but how about NPSHr? We know that the vapour pressure depends ...
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34 views

Any books or websites that anyone would recommend [closed]

I am a secondary/high school student to look into to help with mechanical engineering. I would like to do this for enrichment and as preparation for doing it at university. As well as this I am really ...
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1answer
25 views

Methods of altering the angle of a projectile launch tube

Given some desired release angle, could someone please suggest a way that a machine could alter the angle of a launch tube per feed back from an ultrasonic sensor (I've derived the relation between ...
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1answer
68 views

How can (many) mechanical watches keep track of the current day of the month when these vary so much over months and years?

Having dealt with dates and time in programming context for many years, I have realized what a nightmare our common calendars are, and how much they vary by the year/month/etc. Yet there are fully ...
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2answers
64 views

What are some technical problems with generating electricity using a gas turbine or combustible engine at a gas flaring site?

Numerous oil and gas exploration sites practice flaring for safety and disposal of unwanted low calorific gases. However, instead of just standalone burning the gas, why can't a gas turbine or ...
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33 views

What are some obstacles/issues you face while working in industry? [closed]

As part of a project incubator program at my university, I am trying to understand current specific issues, cumbersome processes, and obstacles facing engineering projects in industry. By pinpointing ...
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2answers
41 views

Will a motor with 1,16 Nm rotate a 50 mm gear moving about 12 kg

I'm not an expert in mechanics, so this is my question. I will buy the motor of the image below to move my door. In the motor shaft, there is a gear with 50 mm of diameter which will move the door. ...
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31 views

FEM degrees of freedom

Consider a "beam". In order to perform modal analysis using the finite element method, the beam is meshed with 2nd order hexa elements. The total count of nodes is 1280. The same beam can be ...
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Question regarding 2D simulation of orthogonal cutting operation on Abaqus

I'm trying to simulate an orthogonal cutting operation on Abaqus, I'm using Dynamic explicit analysis. I have defined my tool as Rigid analytical body and the workpiece is of Ti6Al4V, I have not ...
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2answers
59 views

How much deflection can/should I accept with Aluminum Extrusions?

I plan building things with aluminum extrusions. On this website I can calculate the deflection depending on the profile length and load. https://8020.net/deflection-calculator I.e. if I select a 20/...
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1answer
36 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 ...
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2answers
84 views

Can a beam be too short to experience bending stress?

The question in the title says it all. I've got a a configuration where I'm using a bolt to support a load. The way its set up, the bolt will have a very short cantilever on it. When I calculate the ...

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