All Questions
Tagged with mechanical-engineering materials
273
questions
12
votes
7
answers
8k
views
Why does a gear have extra holes?
In a gear you normally have a center hole for the shaft to be put into. Why do some gears have holes surrounding that center hole?
Is it for weight reasons? Does it add stability? Is it so you can add ...
- 265
11
votes
9
answers
3k
views
Aluminum weight saving
"Aluminum saves weight! Its 3 times lighter than steel!"
Also its 3 times weaker and 3 times softer. When comparing stiffness and strenght to weight ratio, aluminum isnt any better than ...
- 119
11
votes
3
answers
2k
views
Why do beverage can tabs break when bent?
Most people have had the experience of moving the tab of an aluminum can back and forth until it breaks off. It usually only takes a few complete back and forth motions before the tab breaks off.
...
- 10.7k
11
votes
2
answers
887
views
Comparing the performance of glass and granite in a heat storage application
Background
I am working with a small team on a university project to build a greenhouse heat sink. This will pass warm air at the top of the greenhouse down through a chamber underground filled with a ...
- 308
10
votes
4
answers
28k
views
Why does the stress-strain curve decrease?
This is a stress-strain diagram
I have noticed that the curve decreases between points C & D and between E & F.
Why does that happen? I expected the curve to always increase since the ...
- 471
10
votes
2
answers
517
views
Are threads machined from high tensile steel more susceptible to damage?
I have an ASTM A311-04 1.25" diameter round 1050 steel bar that exhibits a tensile strength reading of 155,227 PSI. Normally, we receive material in the 13-133,000 PSI range. The bar is machined to a ...
- 101
10
votes
3
answers
5k
views
How do you select the correct area to consiser for first moment of area calculations?
I have just begun studying mechanics of materials and I am struggling to understand intuitively how to select the area in first moment of area calculations. I was hoping someone has a relatively easy ...
- 299
9
votes
2
answers
3k
views
How can a knife cut through butter?
How does anything actually cut anything, since we all know stuff is made up of atoms and molecules, which can't be touched together (It Requires Binding Energy). So how come we see things all around ...
- 99
9
votes
7
answers
21k
views
Steel selection for building a trailer
I'm thinking about building another trailer. I've built lots of smaller trailers in the past, but this time I'd like to build myself a small tandem axle gooseneck rated for 7,500 lbs.
I am a ...
- 191
8
votes
5
answers
8k
views
How do you attach something temporary to a smooth metal shaft?
I want to attach something small to the smooth metal shaft of a small motor (2-3 mm in diameter), like fan blades, but I want it to be temporary.
If I make it too loose, then the fan won't turn at ...
- 301
8
votes
4
answers
8k
views
Is there a mechanical equivalent to a hi/low pass filter (as in electrical engineering)?
I have been wondering if there are certain media (for instance glass, air, foam, etc.) which are peculiar given their chemical composition and/or structure allowing them to filter out mechanical waves ...
- 81
8
votes
3
answers
592
views
Protecting device from microwaves in microwave oven.. but allowing Bluetooth?
I am building a device that needs to be inside of a microwave oven but somehow needs to communicate with another device outside of the microwave.
How can I reflect microwaves so they don't come into ...
- 183
7
votes
2
answers
5k
views
Why manufacturers prefer Brass over Copper in electrical conductors?
I am working on product where we need pogo pins, as copper is better conductor of electricity I was searching for the copper pogo pins. After about a month of searching, it is come to my notice that ...
- 203
7
votes
2
answers
241
views
Can high alloy tool steels be quenched in brine?
It is will known that most of tool steels are quenched in oil to prevent cracking and distortion which appears when quenching in water due to non-uniform cooling caused by formation of insulating ...
- 81
6
votes
2
answers
2k
views
Does the ultimate tensile strength of a material have a physical meaning?
For example, for yield point you can say that it is a point after which the material will have plastic (permanent) deformation. I'm wondering if there is any similar meaning to the tensile strength? ...
- 351