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Old Dec 1, 2012, 02:32 PM   #1
SomeDudeAsking
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Engineering Lesson for Why the iPhone 5 is Poorly Designed and Bends

http://upload.wikimedia.org/wikipedi...S-N_curves.PNG

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Fatigue limit, endurance limit, and fatigue strength are all expressions used to describe a property of materials: the amplitude (or range) of cyclic stress that can be applied to the material without causing fatigue failure.[1] Ferrous alloys and titanium alloys[2] have a distinct limit, an amplitude below which there appears to be no number of cycles that will cause failure. Other structural metals such as aluminium and copper, do not have a distinct limit and will eventually fail even from small stress amplitudes.
http://en.wikipedia.org/wiki/Fatigue_limit

And boys and girls, what overly thin material with low fatigue life is the iPhone 5 made of?
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Old Dec 1, 2012, 02:54 PM   #2
chambone
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The thing that has really been puzzling me is this; are all these self-appointed metallurgists and engineers just trolling or are they really taking themselves seriously?
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Old Dec 1, 2012, 02:54 PM   #3
burgundyyears
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I don't know about your engineering analysis, but my statistical analysis of your most recent 25 postings is that they are hilariously negative about virtually every aspect of iOS/iOS devices.

I'll keep a nightwatch for a sudden case of the bends however and report back to you forthrightly! We have 10 iP5's at work and counting, surely such a design defect will present itself in such a population, right?
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Old Dec 1, 2012, 02:57 PM   #4
tymaster50
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Goddamn, is everyone an engineer now? Doing basic Wikipedia research doesn't make you an engineer or an "engineering professor"
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Old Dec 1, 2012, 02:58 PM   #5
Yester5
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Here's a tip for you...don't sit on your phone.
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Old Dec 1, 2012, 03:19 PM   #6
scaredpoet
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Quote:
Originally Posted by SomeDudeAsking View Post
And boys and girls, what overly thin material with low fatigue life is the iPhone 5 made of?
What's great about these armchair metallurgists is, they don't even bring up the right facts to bolster their argument.

Material fatigure doesn't refer to how easy something bends, but rather the state in which repeated back and forth bending causes the metal to break clean apart. If you take the metal ring from the top of an aluminum can, for instance, and keep bending it back and forth until it snaps off, that's fatigue.

But as far as I know, we've not had anyone post on here saying "hey guys, I just purposefully bent my iPhone 5 back and forth a dozen or so times and it broke clean in half! I think this is a design flaw."

Cell phones can break if you do silly things with them. So, don't do silly things with them.
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I'm here to talk about Apple stuff, and related tech stuff. Your political beliefs? I really couldn't care less about.
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Old Dec 1, 2012, 03:38 PM   #7
SomeDudeAsking
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Quote:
Originally Posted by scaredpoet View Post
What's great about these armchair metallurgists is, they don't even bring up the right facts to bolster their argument.

Material fatigure doesn't refer to how easy something bends, but rather the state in which repeated back and forth bending causes the metal to break clean apart. If you take the metal ring from the top of an aluminum can, for instance, and keep bending it back and forth until it snaps off, that's fatigue.

But as far as I know, we've not had anyone post on here saying "hey guys, I just purposefully bent my iPhone 5 back and forth a dozen or so times and it broke clean in half! I think this is a design flaw."

Cell phones can break if you do silly things with them. So, don't do silly things with them.
I don't think you are thinking as clearly as I am. If you look at the photos of the bent iPhones, many of them have a break near the volume buttons which is consistent with cyclic stresses causing failure because the area taking the load at that point is the smallest. The smaller material area at the volume buttons can sustain much fewer stress cycles of the same magnitude than other parts of the phone.

----------

Quote:
Originally Posted by burgundyyears View Post
I don't know about your engineering analysis, but my statistical analysis of your most recent 25 postings is that they are hilariously negative about virtually every aspect of iOS/iOS devices.

I'll keep a nightwatch for a sudden case of the bends however and report back to you forthrightly! We have 10 iP5's at work and counting, surely such a design defect will present itself in such a population, right?
Do you understand what stress cycling is?
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Old Dec 1, 2012, 03:45 PM   #8
Serelus
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Wikipedia really? You do realise that the way Apple is producing these iPhone's, cannot be boiled down or traced back into a mere wikipedia page right? Cause if it were that easy, people would be putting together their own iPhones. There's alot more things to consider which you are clearly not thinking of. Thankfully, apple is the one designing these Phones.

http://f.cl.ly/items/243f2k1F0y3q2w3t3c05/Capture.PNG
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Old Dec 1, 2012, 03:49 PM   #9
dukebound85
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As an actual engineer, I am amused. Carry on. I need my entertainment
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Old Dec 1, 2012, 04:13 PM   #10
lbhskier37
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Originally Posted by dukebound85 View Post
As an actual engineer, I am amused. Carry on. I need my entertainment
Me as well. I always enjoy Wikipedia experts.

----------

Quote:
Originally Posted by SomeDudeAsking View Post
I don't think you are thinking as clearly as I am. If you look at the photos of the bent iPhones, many of them have a break near the volume buttons which is consistent with cyclic stresses causing failure because the area taking the load at that point is the smallest. The smaller material area at the volume buttons can sustain much fewer stress cycles of the same magnitude than other parts of the phone.

----------



Do you understand what stress cycling is?


Ahahahahahaha!
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Old Dec 1, 2012, 04:13 PM   #11
Applejuiced
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What?
I thought the iphone broke and bend spontaneously on its own.
There's no way someone would misuse their own device
Blame the manufacturer for making a device that can bend and break.
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Old Dec 1, 2012, 04:14 PM   #12
Esoom
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I don't think the OP realizes what the numbers on the graph scales actually represent.

The phone hasn't been available to the public long enough for anyone outside of a test lab to accumulate 10,000,000+ stress cycles.

Let's say you wear skinny jeans and sit down 100X/day, that gives you 200 stress cycles/day (because the phone is stressed on sitting & getting up), X 365 equals 73,000 stress cycles in a year, so you have 136 years before a failure from metal fatigue.

And I'm the first to admit I know jack about engineering or math, but have read a bit about metal fatigue years ago when I was all into bicycle frames.

Last edited by Esoom; Dec 1, 2012 at 04:23 PM.
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Old Dec 1, 2012, 04:25 PM   #13
dukebound85
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Originally Posted by gecis View Post
"Oh yeah, feed my ego. I'm better than all the retards here". Instead of thinking that I think it will be helpful if you can contribute to this thread by using your "actual engineering" skills.
Why? The entire premise of this thread is wrong. His "lesson" is merely a snippet of what fatigue limit is and has no connection to why an iPhone bends. Bending is not a result of fatigue properties of a metal...

As the poster above me mentioned, the op does not have a feel for the magnitude of cycles that accompanies failure due to fatigue.

The phone bends because people apply a force on it via common actions like sitting on your phone supposably
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Old Dec 1, 2012, 04:44 PM   #14
duneriderltr450
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As a fellow engineer, who give a **** it's just a phone.
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Old Dec 1, 2012, 04:48 PM   #15
utahusker
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Originally Posted by duneriderltr450 View Post
As a fellow engineer, who give a **** it's just a phone.
Agree completely, I think some post condescending statements to see how long the thread can go. Oops!, I just helped achieve his goal.
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Old Dec 1, 2012, 04:57 PM   #16
iRetired
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Speaking as a retired degreed mechanical engineer/college professor, I find it hard to believe that Apple's in-house design and engineering department did not thoroughly analyze a myriad of possible materials beforehand.
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Old Dec 1, 2012, 05:12 PM   #17
iSensei
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WTF, do you people with bent iPhones sit on your Macbook Air/Pro then moan and bitch about it bending? If so, get a rugged phone not an iPhone. Nothing will bend by itself. It's against anything physics.
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Old Dec 1, 2012, 05:20 PM   #18
testcard
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I usually fold my iPhone 5 in half and carry it in my jeans pocket. Am I doing something wrong?
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Old Dec 1, 2012, 06:09 PM   #19
Mrbobb
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Yes you can post graphs, congratulations.
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Old Dec 1, 2012, 06:24 PM   #20
GoSh4rks
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OP has no idea what he is talking about. Fatigue life has nothing to do with why the metal is bending where it is.
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Old Dec 1, 2012, 06:32 PM   #21
djdanny
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People who don't know anything about engineering should not be posting about engineering stuff. Fatigue failure and bending are not the same thing. When you're talking about bending, you're looking at the yield strength of the material and at what point the plastic deformation becomes permanently set. LOL at the guy who is trying to talk about the iPhone bending and fatigue failure in the same sentence.
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Old Dec 1, 2012, 07:08 PM   #22
SomeDudeAsking
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Quote:
Originally Posted by Esoom View Post
I don't think the OP realizes what the numbers on the graph scales actually represent.

The phone hasn't been available to the public long enough for anyone outside of a test lab to accumulate 10,000,000+ stress cycles.

Let's say you wear skinny jeans and sit down 100X/day, that gives you 200 stress cycles/day (because the phone is stressed on sitting & getting up), X 365 equals 73,000 stress cycles in a year, so you have 136 years before a failure from metal fatigue.

And I'm the first to admit I know jack about engineering or math, but have read a bit about metal fatigue years ago when I was all into bicycle frames.
OMG, the people in this thread can't make a connection or see that the left side of that chart doesn't just suddenly end. If you put large stresses on aluminum, the number of cycles to fatigue decreases dramatically. It explains why an iPhone may come out of the box looking fine but after a few weeks of use with the typical stresses a phone may see, parts of the iPhone aluminum will fatigue because the cross sectional area at the volume buttons is so small. When the area at the volume buttons yield, the existing stresses in the aluminum can warp the structure. There are existing stresses in the aluminum of the iPhone because Apple machines it with cutting tools but does not heat treat it to relieve the stress. It's basic engineering people. Those of you who just claim to be engineers bring nothing to the table in terms of a logical engineering explanation.
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Old Dec 1, 2012, 07:21 PM   #23
duneriderltr450
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Quote:
Originally Posted by SomeDudeAsking View Post
OMG, the people in this thread can't make a connection or see that the left side of that chart doesn't just suddenly end. If you put large stresses on aluminum, the number of cycles to fatigue decreases dramatically. It explains why an iPhone may come out of the box looking fine but after a few weeks of use with the typical stresses a phone may see, parts of the iPhone aluminum will fatigue because the cross sectional area at the volume buttons is so small. When the area at the volume buttons yield, the existing stresses in the aluminum can warp the structure. There are existing stresses in the aluminum of the iPhone because Apple machines it with cutting tools but does not heat treat it to relieve the stress. It's basic engineering people. Those of you who just claim to be engineers bring nothing to the table in terms of a logical engineering explanation.
You basically just posted a graph showing how aluminum is weaker than steel. Wow. I think I learned that in 5th grade....
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Old Dec 1, 2012, 07:24 PM   #24
dukebound85
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Do you even know what the unit ksi is? If you did you wouldn't have posted what you did.

Us engineers have told you that fatigue life of a metal and iPhone bending is not the same. What else do you want?




Quote:
Originally Posted by SomeDudeAsking View Post
OMG, the people in this thread can't make a connection or see that the left side of that chart doesn't just suddenly end. If you put large stresses on aluminum, the number of cycles to fatigue decreases dramatically. It explains why an iPhone may come out of the box looking fine but after a few weeks of use with the typical stresses a phone may see, parts of the iPhone aluminum will fatigue because the cross sectional area at the volume buttons is so small. When the area at the volume buttons yield, the existing stresses in the aluminum can warp the structure. There are existing stresses in the aluminum of the iPhone because Apple machines it with cutting tools but does not heat treat it to relieve the stress. It's basic engineering people. Those of you who just claim to be engineers bring nothing to the table in terms of a logical engineering explanation.
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Old Dec 1, 2012, 07:26 PM   #25
ucfgrad93
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Originally Posted by Yester5 View Post
Here's a tip for you...don't sit on your phone.
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Originally Posted by chambone View Post
Upon checking his earlier contributions, a better tip for this person would be to get his donut and pizza augmented ass away from the computer and get a life, or at least find some other way to kill his days.
Even better tip, add SomeDudeAsking to your ignore list.
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