# Machine design Definition and 19 Discussions

Machine Design (ISSN 0024-9114) is an American trade magazine and Web site serving the OEM engineering market. Its print issues reach qualified design engineers and engineering managers twice a month.
Key technologies covered include computer-aided design and manufacturing (CAD/CAM), electrical and electronics, fastening and joining, fluid power, manufacturing, engineered materials, mechanical engineering, and motion control.
Today, Machine Design is owned by Informa, and has editorial offices based in New York, New York and Cleveland, Ohio, USA.

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1. ### "Rigid airship" using low density hydrogen (LDH) inflation

I know now that making a full on vacuum airship is unfeasible for it's compressive properties. So why not just make a rigid airship that is evacuated enough that the hydrogen is no longer significantly dangerous to it's surroundings, using say 25-30% density of neutral hydrogen? What's the...
2. ### Engineering Why are the radial and the axial stress in a rotating thin ring null?

Greetings, while studying the stress in the rotating thing ring and find out the last equation that says I would like to understand why? Thank you!
3. ### Inertia units for a synchronous machine

Hello everyone, I'm sorry if this is not the right sub-forum to post this, but this doubt has been haunting me for a while. I've got some rotatory machine -let's say, generic synchronous machine-. Turns out there are typical values for [kg m^2] (inertia) in the 2-10 range; the software I'm...
4. ### Automotive Factors affecting compression spring oscillations

Hi all, I'm studying the compression spring design issue that occurred in a machine design application. As illustrated below, spring is bouncing or oscillating after impact to a stopping surface (1 -> 2 -> 3 -> 4) and eventually stop after few bounces. Ideal case for this application is to...
5. ### Calculate resultant force of a linear mechanism

Hi all, I'm currently designing a linear to linear transform mechanism (wedge cam design). Would like to check how much force required to push/ slide the roller down. To ease calculation, i have include some assumption: F2 = 1kg @ maximum compressed angle = 20degree F1 required = ? and how...
6. ### Calculate the required torque for a cam design

Hi all, I'm currently designing a cam mechanism. Would like to check how much motor rated torque required for the following design of snail cam ? To ease calculation, i have include some assumed factor as below. Two extreme condition (rotation degree) to compare. What is the motor rated...
7. ### Misc. Project: Single Shaft Shredder

Summary: Single shaft copper shredder I design a rotor of a shredder, but i need to find a motor for the rotor of the shredder. My questions are: 1. What is the best rpm for a copper shredder ( what kind of effects wil the shredder have on high rpm 1200-3000, lower rpm 300-1200 ) 2. what...
8. ### Mechanism with a linear actuator

Designing a machine. For it to work properly there would need to be a mechanism that connects the linear actuator to the stand that would allow for the actuator to move horizontally relatively freely with applied forces at the bottom, when there is simultaneously a downward applied force by the...
9. ### Which force creates the torque?

Homework Statement Homework Equations The Attempt at a Solution F12 is just an internal force caused by the joint 1 right? how can an internal force cause a torque?
10. ### Minimum number of teeth given the gear train ratio?

Homework Statement Homework Equations The Attempt at a Solution for this class, we were not taught with contact ratio equations, nor the pressure angle is given, so for this type of problems, do we just assume that minimum number of teeth on a pinion will be 12? 3 integer factors of 180 can...
11. ### Simple gear train, typo?

Homework Statement Homework Equations The Attempt at a Solution if you do 38*25/pi , you would get 302.394 for the exact pitch circle diameter, similarly, exact d2 should be 907.183 mm, is it a typo? or did I miss something?
12. ### I Phi Machine Help

If you know phi it is about 1.618...=2cos36. The equations when x=phi which is equal to 0 is x^2-x-1=0. I took the first derivative squared and the second derivative cubed. The equation with x=phi is: [2x-1]^2+2^3=13 Check for yourself, if you fill in phi you get 13. Anyway, I do not know what...
13. ### How to further metrology study from machine design approach?

Hello, I have metrology in my 4 semester in Bachelor's of Engineering in Mechanical Engineering. However, the books that we get (Engineering Metrology, R.K Jain,) give only a brief principle of how the instruments work. I want to further my study of this subject with an intention to design...
14. ### Trying to saw a 1/2 in Al rod in half with only 4 AA batteries as the power source

Hi there So we have a group design project in my mechanical systems 2 class and it basically goes as follows: design a mechanism to cut a half inch aluminum bar in half using a standard hacksaw blade and 4 AA batteries. You have to use a motor w/ input > 5000 rpm for the 'main' component we...
15. ### 500 kg Solar CSP reflector dish mechanism problem

I am currently re-fabricating solar concentrator dishes to allow for automatic tracking of the sun during the day and month. The industry term for these dishes is 'CSP' (Concentrated Solar Power). Task at hand: The CSP parabolic dishes are currently manually adjusted to the position of the sun...
16. ### Machine elements stress concentration

Homework Statement A flat part with constant thickness b is loaded in tension as shown. The height changes from 50 to 87 mm with a radius r = 4.0 mm. Find how much lower a load can be transmitted through the bar if the height increases from 50 to 100 mm and the radius increases from 4.0 to 10...
17. ### Machine elements - deflection and stress problem

Homework Statement Homework Equations δ = Pl/AE σ = P/A The Attempt at a Solution I had calculated the deformation for both the steel and aluminum, and added them together to give me δ = 0.481 mm, which is incorrect. I also thought I could simply plug in the force P = 200kN and the...
18. ### I am ready to make a mechanical drawing but have issues

One question is, I need a rod that both has grooved bearing tightly fit and a linear bearing on the same rod with no slop. Is this possible? What is a "press fit" tolerance? If I have a 0.5 hole, what size rod will be press fit? What size will locate without pressing? Boy I wish I had an...
19. ### Torque calculation of an vehicle

hi, i have 8000 lb machine it has 4 wheels (just like car), i want it to move on 2 ft/sec speed on cast iron wheels with steel track at flat surface. radius of every wheel in 5 inch. what will be the torque required to move this machine?? and what will be the torque on each wheel?? i want to...