July 2011 Archives

2015, you're movin' on up to the [north]east side!

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Dear 2015,

 Congratulations! You've almost finished your last summer before college-scary, isn't it?  In less than a month, you're moving in to West Hall.  I know I hadn't seriously thought about packing until...the week before I got on the plane to Boston, but I'm sure [at least, I hope] some of you are thinking about it now and not waiting until last minute like I did! 

Residential Life at Olin

Hey guys!

In my explorations through the Olin website, I've noticed that there isn't that much information about residential life for you guys. I imagine it would be useful to know what Olin looks like, and what we do outside of classes on a regular day. So for all of you who haven't been on a tour, I'll do my best to virtually show you around.

I'm going to take you guys through an average evening - with informational tidbits interspersed.

Best Laid Plans...

There's one lesson I will never forget from working on Carnegie Mellon's Formula SAE Team: "figure out how much time you think a job will take. Then plan for three times that amount". It's surprisingly accurate, actually. I bring it up because I will be flying home on July 30 (in 122.2 hours, according to WolframAlpha) and I had rather hoped to be more or less done with everything. True, there's still an abstract due August 10 and a paper to write, but I could work on that anywhere. The plan was to take data today, do some analysis, get the abstract done, then fly home. I'd enjoy the last month of summer and work on the paper once school got started.

Hopefully that will remain largely true, but I certainly didn't get data collected today. Whilst I am a huge fan of learning by doing, it must be said that it usually results in designing one thing and building something completely different. Having finally got a new airfoil rapid-prototyped, I thought I would "only" have to force an aluminium tube through it and pin a steel rod into said tube. "Only". Ha.

Problem 1: due to the RP machine's resolution, the tube is .05 inches wider than the hole in the wing. Which means hammering the tube all the way through is a) very hard because of friction and b) not a good idea because it'll start to crack the wing in a very important place. Happily, I got around this by using two shorter tubes, one on each end. It occurred to me that only half of the tube is actually transferring load from the steel to the wing, while the other half was just there to hold the thing up. So there, problem averted.

Problem 2: I tried pinning the tube and the steel together over the weekend. They didn't want to play nicely, so I gave up and tried again this morning. There were playing slightly nicer and then the spring steel broke altogether. Oops. Now I could try making a new piece of spring steel, but Carnegie Mellon taught me another valuable lesson: when something breaks, it usually means that the design is no good, not that you were unlucky. In other words, if you build the same thing again, it will break the same way...again. Back to the improvisational-drawing board! I believe I've worked out a way to avoid the problem, but it involves a tool that is currently locked in the machine shop...which won't be open until Wednesday. Arg.

Like I said: figure out how much you need, then multiply it by three.


Everybody's lookin' forward to the weekend, weekend

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Partyin' partyin' YEAH!

Haha, yeah we just trolled you!

This time around I figured I would team up with your other favorite student blogger, Jordyn! During the school year our minds are filled with circuits, CAD models, MATLAB code, problem sets [HIGH FIVE OXFORD COMMA], and the like, but in the summer we have so much free time that we don't really know what to do!

Despite this, we have done a good job keeping ourselves occupied. Check out some of our adventures!

In the name of science!

Wow, the past month has certainly flown by!  I wanted to share my life in the bio lab along with some of my scientific Boston adventures with you.

This is what I do every day-including the weekends!


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Okay, I was slightly kidding. The above photos are from a weekend trip to Boston, at the Let's Talk About Food Festival.  My friend Kat (Wellesley '14, left) and I were food scientists-complete with pipettes and goggles- at an event sponsored by the Boston Museum of Science. I really wish I owned a pair of green safety glasses!  In reality, I don't go into the lab during weekends [yet], and I tend to look more like this:


Long Time, No See!

Wow, it's been a whole month since I posted anything - and only three weeks until I leave, too! It's hard to believe things have gone by so quickly, especially since there's still so much to do! Okay, enough with the exclamation points, but time really has flown by.

Let's start with a situation report on my research. Last time we spoke I was still working on getting the flutter jig back together. Sadly, I still don't have a new wing because the person in charge of the rapid prototyping machine has gone on vacation. As such, we got to work on the electrical systems. There are three channels to take data from: the linear displacement &angular position of the wing and the current generated in the harvester. We have a laser displacement sensor for the wing displacement and are measuring the voltage drop across a resistor for the harvester. Those are nice easy measurements akin to the measurements we'd make in Modeling & Control.

Angular position is a little harder. For that we need an optical quadrature encoder (yay for big impressive names). I had been told it was also a straightforward "plug-and-play" type sensor. A week of banging my head against a wall revealed that it wasn't. It helped me confirm that I want to be a mechanical engineer, not an electrical engineer, though. For MEs, you can spot flaws by looking at the enormous crack or the fire or the leak. Sometimes EEs can spot flaws by fire, but mostly it's a lot of poking around with a multi-meter and scratching heads. The worst part of the story is that there wasn't an impressive problem that no one would have spotted and oh-aren't-we-so-clever. No. I need a couple pull-up resistors to help get the current right. Garland (a gentleman who helps our SCOPE teams a lot) came to take a look at it for me and diagnosed the problem immediately. But in the end, all of our electrical stuff works just fine. And it's all neatly arranged and organized.

Next step was to "characterize the harvester". It's basically a spring, so we needed to know what it's stiffness (how much force it exerts per distance displaced) was and how damped it was (how long does it take it to go from maximum vibration to zero?). Sparing the technical details, I got to play with big aluminium versions of Lego and made the two jigs below.

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"Custom" = "Improvised"

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It turns out that business cards make great laser sights!

And then came the math. So much math. MATLAB made interpreting the data collected easy, but I'm currently in the midst of developing a model to actually put them in. There exists a nice mathematical model for flutter, but it makes some assumptions that are no longer true. Because we've added the harvester to the jig, we have to add the damping and stiffness of the harvester, too. Damping is easy, that fits into an existing part of the model. But because of the way magnets work, the stiffness of the harvester is not like the stiffness of a spring. A spring is linear - pushing a spring twice as far takes twice as much force. It turns out that our harvester's stiffness is best characterized by a 5th-degree polynomial, not a straight line. So we have to add a bunch of terms that make the math...less pretty. And then you have to re-arrange it and make the thing look like something you could solve in MatLab. As I said, I'm a Mech. E., so this is all a crazy and absurd exercise that is surely impossible great learning opportunity.

As I said, I have three weeks left before I leave, then another ten days after that before the abstract for the research conference is due. Hopefully I can get the math sorted next week, but there isn't huge pressure since we can't take any usable data until the new wing is made.

And that's where my research stands at the moment. I'll make sure to keep you in the loop as we get closer to the finish. Until next time!

Auf wiedersehen,

-B

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Recent Comments

  • Mel (Olin '07): I so wish I could be there to see the read more
  • Kevin Tostado: What time are the performances? As an alum in the read more
  • Brittany L. Strachota: Looks like a huge success! Keep it up. :) read more
  • Kimly Do: also also, an electric water kettle is not really necessary, read more
  • Brittany L. Strachota: We shall see. Though, 150 is an awful lot of read more
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  • Brittany L. Strachota: I want cookies! Also, don't forget, kids, you WILL be read more
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  • Jordyn Burger: Yep! Congrats, Brendan's gonna give you cookies! [I'll let him read more
  • CSF: Is the title from The Jeffersons? read more