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.

Filter by
Sorted by
Tagged with
0
votes
0answers
24 views

What does the author mean? Turbomachinery - Reaction

I am reading a book of Fundamental Energy Systems. The author describes the rate of change in head for a turbomachine as: $$ \frac{1}{2}[(V_1^2-V_2^2)+(U_1^2-U_2^2)+(V_{R2}^2-V_{R1}^2)] = H =U_1V_{u1} ...
0
votes
2answers
30 views

Why doesn't my pen ballpoint or nib emerge?

https://i.imgur.com/SfdRluq.mp4. This shows a working pen. How can I make the GIF show up? When I rotate that silver part on the broken pen, the nib doesn't emerge.
0
votes
2answers
15 views

Looking for feedback on a lift bed power lift mechanism

I built a king size lift bed. I want to add a powered lift mechanism to raise and lower it to access the storage area under it. In order to get the height I want when the bed is raised, I'll need ...
0
votes
1answer
18 views

How to find angle using Torque-Inertia

I want to find angle(radians) using the formula: τ = Iα . I guess after finding angular acceleration α I have to do an integration but I am not sure which method I should use. Thanks
0
votes
1answer
29 views

Is it possible to find heat flux without emissivity value?

In this question there is a value given for absorptivity of infrared radiation however in order to work out a value for heat flux emitted from the solar panel in order to answer part (a) surely I'd ...
0
votes
4answers
41 views

When using an o-ring as a face seal, are the faces flush together?

I'm using an o-ring in a face seal, external pressure configuration as a seal between two metal parts. Are the two faces being compressed and sealed going to be flush together or will there be a gap ...
1
vote
1answer
22 views

Derivaiton of maximum deflection of a cantilever beam with intermediate load

I am trying to derive the maximum deflection of a cantilever beam. L is the length of the beam and a is the where force is applied. For the case 0<x<a, I use the method below and it gives me the ...
0
votes
0answers
25 views

How can I derive the equations of motions to get this into a three degrees of freedom matrix form? [closed]

How can I derive the equations of motions to get this into a three degrees of freedom matrix form? The bar of mass m1 (assumed to be rigid). edit: Newton's Law sum Fx2=mddot{x2} mddot{x2}-k3(x2-x1)=0
1
vote
2answers
37 views

Can a vacuum in a room increase the pressure in a tube?

Ok, So I work as a Marine Engineer but I do not have an engineering degree so I am having a hard time wrapping my head around this problem. So currently on my ship we had a minor spill overboard from ...
0
votes
1answer
5 views

Calculating Gearing Ratio from Constrained Rotational Linear Arc and Horizontally Opposed Rotation

I'm 3D printing an aircraft throttle unit as a POC and am trying to calculate the gearing ratios that are required in order transfer the full range of linear motion into a directionally opposed sensor ...
4
votes
4answers
2k views

Benefit of removing the center “engine hub” inside a fan

Most fans (small and large) have inner hubs (see image left). Would there be a gain in efficiency by removing that center hub, thus creating more blade space? You could fix the blades to an outer ring ...
2
votes
1answer
28 views

Gear Ratio of a Stepped Planetary Gearset

I was looking into planetary gearsets, and came upon the concept of a stepped planetary gearset. In the image shown above, if my input was the blue sun gear, the output was the planet gear, and the ...
1
vote
2answers
53 views

Quicker way to weld hexagonal nuts in honeycomb pattern

I am currently designed a structure that require hexagonal nuts to be placed side by side in honeycomb pattern, welded upon sheet. Other than doing it in old-fashioned way, is there any way/technique/...
2
votes
3answers
76 views

How can deflection and spring constant of cantilever beam stack be calculated?

How can I calculate some properties of a stack of 2 bonded cantilever beams like in the image? Especially I am interested in the spring constant and deflection with force on random locations. However, ...
0
votes
1answer
31 views

Question in finding the direction of forces in a truss

This question primarily involves finding the direction of forces in a truss. Let's give a scenario in Method of Joints One source I found says that in finding the direction of the source, it would be ...
1
vote
0answers
36 views
+50

Calculating time derivatives of stress (σ ) in the constitutive equation of a viscoelastic model without explicitly remembering the prior stress?

I am trying to understand how to work with viscoelastic models. There are numerous simple viscoelastic models (described at that link). In each, there is a "constitutive relationship" ...
1
vote
1answer
45 views

What exactly is Hooke's law defined for?

I used to think that Hooke's law was a relationship between how much a bar under uniaxial loading deformed and the internal force (per unit area) that developed within that bar. But this clearly isn't ...
0
votes
2answers
46 views

Shearing Stress at the Boundaries of two infinite Planes

This is a worked example on a book I am reading (Fundamentals of fluid Mechanics). He then asks "Can you explain the change in sign? [Hint: Sketch a sheared fluid particle adjacent to the top ...
0
votes
0answers
17 views

Reference for Engineering/Technical Drawings [closed]

Is there a good reference for engineering drawings? Unfortunately, my mechanical engineering coursework did not provide enough material for this topic. It seems like drawings are an afterthought for ...
0
votes
0answers
9 views

Quantifying the amount of structural/hysteretic vibrational damping that occurs in proportion to deformation? (ie. Based on how “bent” something is?)

Three different conceptual types of vibrational damping forces are described here: Viscous: $f(t) = -c \cdot v$ Coulomb: $f(t) = -c \cdot \text{sgn}(v)$ Structural: $f(t) = -c \cdot |x| \cdot \text{...
1
vote
1answer
49 views

Simple Flour Dispenser

I am trying to make a simple dispenser without using any electricity. I just want to create a simple dispenser that dispenses flour with the turn of a knob. I am creating this because wherever I bake, ...
0
votes
1answer
25 views

Using the method of joints, determine the force in each member of the truss shown [closed]

How to find the force in each member of the truss using method of joints?
0
votes
1answer
26 views

Simple EEPROM Code for Arduino to act as a Boolean

So I'm new to using Arduino's in general and just want to have my code by reversed each subsequent startup using the eeprom on my Arduino uno. I've been trying to read up on how to use the eeprom but ...
1
vote
3answers
65 views

Usage of the three-sigma limits in calculating minimum force

I have carried out 10 cantilever sample tests that provide a braking force as follows (in kN): 22.1, 20.98, 21.03, 20.7, 21.03, 21.09, 20.98, 21.08, 21.24, 21.19 The goal is to recommend the worst ...
0
votes
0answers
11 views

Finding an “end of tube fixation”

I recently saw this kind of "end of tube fixation design" on a website (see picture): I am more specifically interested to the "fixation head with 3 screws". Basically, this is an ...
1
vote
1answer
44 views

How to make a stepper motor retract on power loss with arduino?

I am trying to make a stepper motor rotate a poster down (like a motorized projected screen) upon the Arduino receiving power, when the Arduino loses power for it to retract. The reasoning behind this ...
0
votes
1answer
29 views

Identify bearing dimensions from its bearing number

In motors/pumps generally following bearings are used (ref: https://www.nke.at/en/bearings-applications/applications/electrical-motors): Deep groove ball bearings Cylindrical roller bearings Angular ...
1
vote
1answer
35 views

Reinforce foldable table legs

I'm trying to build a table with 4 swivel legs that can be locked into arbitrary angles so that it can stand over one to three rows of storage crates in my garage: As you can see, the legs aren't ...
2
votes
1answer
24 views

How to size motor to pull up a slope

I am trying to understand how to size an electric motor to pull a person up a sloped incline. I know that I need to take into account the speed desired, the weight of the person and the friction/...
0
votes
0answers
40 views

Do any roller coasters actually use the brachistochrone curve?

Not sure if this is the right place to ask this. But I'm assuming roller coasters are related to engineering. I know that in theory, the brachistochrone curve is the fastest way from point A to point ...
1
vote
0answers
12 views

Difference in the properties arising from precipitates and intermettallics

What are the key differences in the mechanical properties caused by precipitates and intermettallics in metal alloys? So far I've found that intermettallics are larger phases, and are usually hard and ...
1
vote
1answer
36 views

What is the best way to fasten securely a load onto a hollow brick?

Due to the ongoing COVID pandemic, I decided to put a basketball hoop on one of our outside walls, so that me and my son can stretch a bit. The problem is that the wall I plan to put the basketball is ...
1
vote
1answer
32 views

What's the best FEA software if you want reliable data [closed]

What's the best FEA software if you want reliable data and are a beginner? So, I've never used FEA software before so I want to learn one that is powerful and relatively approachable. I am most ...
1
vote
0answers
13 views

How to analyse a TEC cooler in the ansys workbench software?

I am currently doing a project on Thermoelectric Coolers . I don't have any experience in the Ansys Workbench software , but we have to do the analysis of the cooler . The device pretty much consists ...
1
vote
1answer
19 views

Off the shelf solutions to problem of 2 way to 1 way rotation [closed]

Looking for commercial off the shelf solutions for 2 way rotation to 1 way rotation. For instance, at the input there is the possibility of clockwise and counterclockwise rotation. Regardless of the ...
1
vote
2answers
28 views

Modelling an annular ring

I am trying to model the shear failure of an annular ring with a uniformly distributed pressure, the ring is hashed out. I am not sure how the problem would be modelled as part of the ring is ...
1
vote
1answer
29 views

3D printer printing out cotton-candy like material after repeated use

I recently purchased a JGMaker Magic 3D printer. It worked well for about 3 months [first picture], but now it is having a lot of trouble. As you can see in the images below, when printing new pieces, ...
1
vote
2answers
38 views

Selecting the right DC motor for horizontal motion

I have come across a problem that for the life of me I can't seem to figure out. I'm sharing this here in the hopes that the amazing community here can help push me in the right direction. The problem ...
2
votes
2answers
50 views

Convert torsional stiffness to translational stiffness

I have an intermediate shaft that drives my spindle with pitch (3). On the spindle there is a slide which is moved translationally by the spindle. My intermediate shaft is rubbery and has a very low ...
0
votes
2answers
40 views

How to calculate the force required to lift this deck?

I want to build a folding deck. both sides are on wheels. Trying to wind my head around how to calculate the required force for the hydraulic piston to be able to pull the deck into a folded position.....
1
vote
0answers
64 views

Calculate fan power

I was wondering how to calculate the required fan power for the following air pipe network. Other losses besides friction is not calculated for. Known parameters: Fan provided flow, VA = 3000 m3/h ...
0
votes
1answer
26 views

How to reduce surface friction when pushing a gear sideways in shaft direction

I'm thinking of a system where a gear engages and disengages by shifting it along the shaft axis. I want to use an arm/board from a servo to push the gear in and out of position, but I'm worried about ...
0
votes
1answer
27 views

How to negate rotation of a rotating linear guide rail on a carriage?

We would like a carriage mounted element (CME) on a rotating linear guide rail (LGR) that negates the LGR rotation and thusly remains rotationally stationary relative to the LGR's pivot affixation ...
2
votes
1answer
56 views

How can I decrease strip tension with bridle rolls in tension leveller?

I'm working on a tension leveller design which consists of 3 main sections. These are Input Bridle Rolls Zone: Increase the strip tension coming out of the decoiler. Leveller Zone: Strip goes through ...
0
votes
1answer
28 views

How to determine the torque and rpm of a Stirling engine?

I am actually working on making of a Stirling engine. I did some research work but most of the content on the internet is qualitative. So I am trying to build a small scale Stirling engine and trying ...
1
vote
1answer
35 views

Pacejka's Magic Formula:Nominal vertical load on tire

To work with Magic Formula for load dependent conditions, we have to use some of additional parameters. In this link, you can find the formula about this. What is the meaning of Fz0 (Nominal vertical ...
1
vote
1answer
40 views

How to mechanically attach a compression spring to a flat surface

I am working on a new project right now and I was wondering if anyone had any ideas on how to keep a spring fixed and connected to this flat plastic piece [image shown below]. Our goal is to keep the ...
1
vote
2answers
622 views

What is this mechanical device and what does it measure?

I’m thinking some kind of torque measuring device but I can’t find confirmation.
0
votes
0answers
21 views

Using a thermos flask as a vacuum chamber

I want to create a vacuum chamber (-900 mbar) that can withstand heat (120°C). I thought about using a pressure cooker similar to most DIY vacuum chambers, but then thought about using a large food ...
1
vote
1answer
59 views

Is air a pure substance?

I was referring to some Thermodynamics text books and found that their definitions of a "pure substance" seem very subjective. "Air, for example, is a mixture of several gases, but it ...

1
2 3 4 5
58