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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55 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 ...
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1answer
40 views

Find frictional losses as box exits ramp

I have a box traveling on a ramp just before the ramp levels out. At this point all values are known: I want to calculate the frictional losses from this point to when the box is completely off the ...
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24 views

Help sizing of lug attachment flange/plate?

Apologies for the crude drawing attached, but here goes. Given Fx, Fy, and Fz loads applied at the lug hole, I've distributed the loading into each of the 6 fasteners to size them. I've also sized the ...
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29 views

Interference fit advice for permanent assembly

Many bicycle cranks have permanently assembled spindles on one side, as shown in the picture. This is a steel spindle inside an aluminum crank arm. I am not sure how these are manufactured. But I ...
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1answer
53 views

How to control a mechanical part using a button(on/off) on a motorcycle?

I don't know how to correctly write the question. I have no background knowledge of electronics engineering. I was wondering for instance, How to open and close the Motorcycle Stand using the On/Off ...
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24 views

Why does use with air or water reduce the maximum temperature of certain high temperature / pressure hoses?

This example is a Parker Hannifin model 426/436 "SAE 100 R1 AT / SAE 100 R16 High Temperature Hose". Here are the temperature specifications: (Full data sheet) Although there is an asterisk ...
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20 views

multidimensional function for object description

I want to simulate a bow tie antenna and build it up with a function. so far i have managed to create a piece of cake with sin and cos. Now I would like to expand the function and round off the ...
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0answers
25 views

High articulation joints

Looking for advice or suggestions for high articulation joints (>57°) for an automotive halfshaft. Peak operating conditions are in the ballpark of ~1000RPM, ~300ft-lb torque. I've considered u-...
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3answers
89 views

Failure in Hollow, Thin Beam due to Collapse of Cross Section

I'm having trouble figuring out how to predict the failure of a hollow channel due to bending. If I'm correct, for a beam with a static second moment of area, $I$, the following equation could be used ...
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27 views

Is it practical to increase engine efficiency by preheating petrol from engine heat waste ? is it applied in any automobile?

I found some article related to preheating the fuel to increase fuel efficiency, but I rarely see such implementation, I assume that it's less effective compared to others But is it really possible ...
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32 views

Increase in internal energy and temperature

A banquet hall (150 m3) is to be used for a formal dinner for 20 persons. Each person occupies 0.075 m3 of space and has an average heat transfer rate of 500 kJ/hr. If the AC system fails, determine ...
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25 views

How do I determine the pitch/roll stability of a buoy?

I am designing a loosely-moored spar buoy (large height relative to width), and the equipment on top needs to remain as vertical as possible while floating in the sea, within limitations of buoy cost, ...
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3answers
129 views

Are stuffing boxes still relevant?

Three problems: Internal friction due to stuffing materials. - Why does it not matter? If it does then there must be some limits like rpm etc. Not entirely leak proof. - Why are we supposed to keep ...
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41 views

How much torque is needed to mix melted marshmallow with rice krispie?

I am designing a robot to make rice krispie treats! More specifically, I want to use a fork to mix the melted marshmallow with rice krispie. I am currently specing out the motor, and since marshmallow+...
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43 views

Can we calculate the torque acting on the last gear determine teeth of the gears of the gear train in the below addressed manner?

The specifications of the generator is as follows: Efficiency- 70% Rated Torque- 0.56Nm Rated current- 14.3A Voltage- 24V Rotor shaft dimension- 1cm(diameter) The ...
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16 views

Why the variable “r” appears in circumferential force balance for a membrane

I am trying to understand a force balance for an inflating membrane (reference cited at the bottom of the post) and can't figure out why there is an "r" in the circumferential balance. The ...
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61 views

A Variable Valve Timing (VVT) engine with exhaust GT added, with and without Turbo Charger applied to the crankshaft?

This topic is the follow-up to the original topic: Why are turbo compound engines not more widely used? Why are turbo compound engines not more widely used? Please, do understand that I am a pure ...
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84 views

Open bearings in a Schaublin 70?

I would like to clean and change de belt in a Schaublin 70 Lathe, but when removing the main shaft, I noticed this weird bearings: How would I remove it what should I take care about?
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58 views

UV radiation simulation in ANSYS

I am setting up a simulation in fluent to estimate the UV radiation dosage of an air stream passing through a cylindrical duct with the UV source in line with its main axis. It is a very simple system,...
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0answers
28 views

How to weld a copper flange with a Nickel alloy pipe?

I have a copper flange and I want to weld it to a nickel alloy pipe. Normally, which welding technique is used to join these two parts? Also what is the filler material to be used to weld a copper ...
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21 views

Should I use brass compression fitting on brass tube?

I would like to use brass compression fitting on brass tube, I am confused because I have seen all the fittings that are used for copper and steel tube only. Is there and disadvantages?
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30 views

Where do I learn about jewel bearings?

I would like to take a deep dive into the world of jewel sourced watchmaking components (including, but not limited to, bearings) but I am having trouble finding any textbooks on the subject. Are ...
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0answers
18 views

Secure loads to gearbox shafts

I have a sculpture that is designed to rotate over 3 axes at max. 30RPM and is mounted on an aluminium disc. My plan is to use 3 of these geared steppers and secure the sculpture to the Z-axis shaft, ...
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48 views

What is the difference between sommerfield number and bearing characteristic number in bearing design?

After reading a few texts on the topic of sliding contact bearings I am confused between the bearing characteristic number and the sommerfield number. As per J.E shigley's text both bearing ...
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111 views

How does a power hacksaw lift on the forward stroke?

Hacksaw blades cut on the pull stroke (back into the machine) and are supposed to lift on the push stroke, all the DIY setups I have seen cut on both the pull and push stroke, i.e. What type of setup ...
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19 views

Deformation gradient tensor from particle displacements in an inflating material

I don't have a mechanics background, but am trying very hard to read and understand how to approach this problem. I am struggling with understanding what's "correct" or the basic process of going from ...
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1answer
100 views

Calculate Torque Required

I am working on a school project that requires me to build a machine. I have designed the machine but I am stuck at torque calculation. The problem goes like this, the machine supposes to rotate a ...
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0answers
22 views

What are the hypersonic Normal shock relationships?

I am learning about hypersonic flow now and there seems to be a lot of discussion about the oblique shock relationships as the Mach tends to be very large. I was wondering what happens to the normal ...
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0answers
31 views

Determinating Reactions for the following frame

According to the frame below, the goal is to determine the reactions of this frame in order to draw after the diagrams N, T and M. The frame is asymmetric by reference at point C. All reactions ...
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35 views

maintenance of steady flow through pressure or mass flow

let's say I have two points in a line, A and B. Between them there is a valve that can regulate the amount of the stream from A to B. Considering that there is a steady flow of the stream between A ...
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24 views

WEC linear inputs

I have seen some designs being made for linear generators for WEC(wave energy) applications. A buoy driving a shaft. But what if the shaft inside was a rack and pinion? If you converted the ...
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14 views

How can I learn the standards(EN,ANSI,ISO) which is related to “roller hemming method in automotive industry”?

There is a method using in automotive industry which is called roller hemming. I have a project about this method but before beginning the project I need to learn the standards(EN,ANSI or ISO) which ...
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0answers
40 views

Clamping Force required

I am currently working on a design for a beer pump (liquid dispenser) of (15 kg approx.), that will be clamped to a table with 2 clamps. This component has a handle attached to the top, where ...
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80 views

How many kWh this turbine would generate?

My grandfather and I are running some experiments down the river, however we don't have expertise in engineering so I bring up this question to the community and hope someone could help. How many kWh ...
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1answer
130 views

How to calculate the required torque for an azimuth/elevation antenna rotator?

I want to build an antenna rotator for a 1M dish. How do I calculate the required torque for the motor of the elevation axis? Here's a sketch of the problem: If the "bottom" of the dish is the pivot ...
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36 views

RSS Tolerance calculation and usage

From my experience, I've been calculating RSS tolerances by squaring all relevant tolerances, summing them up and then square rooting the sums... ie: RSS=[Σ(tol^2)]^0.5 I've also heard of other ...
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37 views

Launching a ball with springs or with elastic bands

I’m a student and have to create a machine that can launch a small bowling ball to knock over some pins. I was thinking that I could use elastic potential energy to launch the ball but I’m not sure ...
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83 views

Wobbling DC motor head

I have used 250 watt DC motor, for DIY electric potters wheel. Motor rated with RPM 3300 and geared reduction to 330 RPM. The issue I am facing is wobbling of the motor head. This issue is with the ...
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0answers
29 views

Bevel gear friction and inertia calculation

I want to calculate the friction and inertia between 2 bevel gears with straight teeth. I know how to calculate those parameters between regular gears with straight teeth. Is there any difference for ...
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0answers
18 views

Clutch for high-speed operation (>40 000 rpm)

I'm currently working on a setup where at some operations my motor has to drive a shaft up to the motor's maximum operating speed (12,000rpm) and a torque of ~0.14Nm but at other conditions this shaft ...
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0answers
45 views

Is there a standards organization or methodology to determine the elastic material properties of common materials?

Is there a standards organization or methodology to determine the elastic material properties of common materials? What constants are normally used to define these properties? More specifically, the ...
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0answers
47 views

Tolerance Analysis on clearance holes

I am designing an enclosure that holds a lens (clearance fit) and a photodiode on a PCB. The alignment of the photodiode to the lens must be pretty tight, thus I am using a boss on the enclosure (also ...
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91 views

How can I calculate the shear modulus (Gxy) for the material of a composite laminate [10/-10/-10/10] using test data?

I have the data from a tensile test including axial displacement, force, and strain, as well as E1, E2, Nu12, and Nu21 for the carbon fiber prepreg. I am trying to use this axial data to calculate Gxy ...
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36 views

Calculation for lowering temperature in a room… room-fridge with water mist?

I was looking at how the water cools my body when it evaporates off it. Then I thought the specific heat capacity could be used to calculate how much energy (i.e heat) would be taken out of a room ...
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46 views

Strut Angle Vs Overhang

I have a 10mm metal disk that is 1mm thick. It is easily bent when a force is applied (green arrow) to the unsupported edge. I need to add a strut, but at what angle? The part is weight-sensitive, ...
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0answers
15 views

Why is a mold required in isostatic pressing after performing Sintering

After an a object is formed through direct laser sintering, as a post-processing procedure the object is sent for hot-isostatic pressing, In hot isostatic pressing the sintered object is placed in a ...
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2answers
164 views

How to determine the deflection of a wire mesh under wind load?

I am trying to extend a metal wire mesh over a large distance, while tensioning it to limit the deflection of the mesh due to the wind as much as possible. After doing some research I came across ...
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0answers
30 views

Solar Radiation Environmental Test Duration

I am designing an outdoor sensor and I need to test it for continuous outdoors service. One of the test I wish to perform is a solar radiation test for the actinic effect (like procedure 2 in MIL-STD-...
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0answers
20 views

Questions on Na2Cr2O7 turning to a vapor phase in 2500F furnace. And possible ways, if any, to filter it

I've looked for answers without success, so turn to the experts. At air temperature, solid-phase sodium dichromate (Na2Cr2O7) -- or the equivalent, sodium dichromate dihydrate (Na2Cr2O72H2O) -- is ...
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33 views

Design of fan pipe for propelling glitter

I am trying to create a prototype for a glitter shooting mechanism. It is worth mentioning that I have no experience with mechanical engineering or fluid dynamics. I think the below image describes ...

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