16 March, 2006

Time-Dependent Failure: Fatigue, or, Unlikely metaphors and far-fetched analogies for your reading pleasure.

In engineering-speak [help me out, engineers, if I mess this up], stress has to do with ‘load’ and strain has to do with ‘extension.’ A material’s capacity for stress and strain can be measured while subjecting the specimen to either tension or compression. The thing is, I am not a static material, but I feel like I have been bearing weight and being over-extended simultaneously, whilst being both stretched and squeezed. Does that seem unhealthy to anyone else?

Out of concern and curiosity, I decided to look into the mechanics of this a little more. It seems that with ductile materials (such as aluminum), strain and stress cause a process that includes things like: deformation*, a yield point**, a degree of elasticity***, something called strain hardening****, a point of ultimate strength*****, and a necking region****** all before the material reaches a breaking point*******.

With brittle materials, on the other hand, the point of ultimate strength is the point of rupture- so there can be toughness, but only up to a single breaking point, and then it is all over.

So, I’m pretty sure the moral of all this is that we should all strive to be as ductile (“able to be molded or shaped without breaking”) as possible.

*I feel comfortable admitting some psychological and emotional deformity.
**Something has to give sooner or later.
***Learning to be flexible is essential.
****This might have something to do with the uncomfortable and rigid contortions people go through when they are just plain trying too hard.
*****Ultimate Frisbee skills are important.
******”Necking region”? Hmmm, sounds risqué…I vote yes.
*******Which seems to be right about now (funk soul brother, check it out now…)


Jesse Putnam said...

This is brilliant. This makes me want to be an engineer again. I am going to reread my textbooks again tonight. thank you thank you thank you.

pete zagorda said...

wow, i thought alexis looking into this stuff was really nerdy, but jesse, you win, what is really sad is that i don't doubt you have already reread your books. i didn't even read any of mine once. good research though lexi, i'm impressed, i was thinking, she wont be able to out-do the ideal gas stuff, you did!

pete zagorda said...

oh yeah, and i'm down with the necking region, hopefully we will be in different ones though, wow that would be awkward.

Alexis said...

responses, in reverse order:

1) sick
2) thank you, i only wish that all my engineering buddies in virginia read my blog so that my efforts would have impressed more people. seriously, though, i think i need to take a break from willfully pursuing nerdiness for a while- hold me to it!
3) thank you (i didn't know you were an ex-engineer! congrats...i think?), and don't hurt yourself

Brian said...

thats incredible. you've taken away all opportunity to talk over anyones head with nerd speak. Please don't do a post regarding thermodynamics or i'll have nothing left to lord over people.

Alexis said...

thermo-dyna-who? no worries there, lord away. seriously, though, you should update your blog.