Made By Monkeys

As we come up on the six year anniversary of the World Trade Center attack of September 11, 2001, it reminded me of an article published last year in Design News based on my interview with a University of California professor of Civil Engineering. After conducting extensive simulation studies of the collapse, he concluded that the buildings could have survived, had one bad design decision not led to another:

“The simulation model shows the plane slicing right through the outer walls of the building like it was a flimsy egg crate,”Professor Abolhassen Astareh-Asi explained. “Because of their unique design, the buildings essentially had no robustness to withstand the impact of a medium-sized plane flying into them at 800 miles per hour.”

The announcement last month that 46 million Nokia-branded lithium-ion (Li-ion) batteries made by Matsushita Battery Industrial could potentially short circuit and overheat was just the latest in a spate of product advisories and recalls of the technology over the past two years.

But it’s not as if Li-ion batteries are at the early point in their life cycle when you would expect these sorts of problems to crop up. Sony invented the technology back in 1990. So why is it failing now?

The theories behind the technology’s recent spotty performance are complex and varied, which makes fixing the problem a perplexing engineering challenge.

Plastics often get a bad rap for being flimsy and cheap., But big hunks of metal aren't immune to failing catastrophically.. Ken Russell, a forensic engineer and professor of materials science at MIT, describes the disastrous effects when monkeys substituted poorly cast aluminum for forged steel in a motorcycle brake. The SEM micrograph shows crack-inducing pores and oxide film in an aluminum casting with hydrogen porosity of the kind he describes..

Roger Platt gleefully spotted this heavily shaded, solar-powered parking meter in Bargates Car park, High Street, Burton upon Trent. He wonders if the fact that the area is famous for beer and brewing had something to do with the decision to locate it under a leafy canopy and notes the irony in chopping branches or cutting down trees to accommodate these environmentally-friendly devices.

The website Ecofriend also notes that the UK's notoriously gloomy weather has plagued the performance of these meters. Adding further to the woes -- Platt says he's noticed a number of these panels installed facing North, something he says "your average Boy Scout can figure out is not the best direction to point a solar panel."

The recent brouhaha in this blog over the underwhelming performance of lithium ion batteries and the care that must be taking when charging them reminded me of a case in Design News that involved an explosion of near-Hindenburg-like proportions

Oh I know what you're thinking -- it's those incredibly thermodynamically unstable lithium ion batteries up to their old tricks again. Wrong!! This culprint in this case was a lead acid battery for a lift truck.

Let's just say the sucker really got shredded, as noted by Myron Boyajian, the forensic engineer who was called in to investigate the case on behalf of the singed plaintiff:

"If a lead-acid battery could discharge and charge with perfect electrochemical efficiency, there would be no emission of hydrogen or oxygen gas, just the quiet conversion of the plate material, one of lead and the other of lead oxide, both to lead sulfate while the sulfuric acid electrolyte changed to water while discharging; and the reversal of this process during charging.
One hundred percent efficiency, like perfection, is only to be hoped for. Excess or rapid charging/discharging, plate age and condition, excessive temperature, and other reasons may cause hydrogen and oxygen gas to be emitted from a lead-acid battery."

And kapow!

When it comes to lingerie, my requirements are pretty straightforward: comfort and appearance. No small engineering feat, given that fabric per se is an unwieldy and challenging structural material. The fact that it is weak in compression is particularly problematic in a bra, whose main job is to lift and support a distributed, cantilevered load. Brush up on the physics of bras here.

A new study released last week by two Canadian researchers reveals that design flaws are responsible for 75% of all toy recalls, and that this percentage has remained consistent since 1988.

The authors of the study say these design problems potentially can be avoided in the future by improving organizational communication and learning. They plan to investigate how organizations can more effectively learn from their own and other’s mistakes and capture and exploit that knowledge.

But the study also raises troubling questions about the diligence of the engineering and design effort, and whether the beleaguered engineering community is being called upon to do too much with too few resources.

In a study last year by Design News, 70% of the design engineers surveyed reported that they are being called upon to take on an ever-increasing amount of tasks and responsibilities. Over 50% said they were involved in more engineering disciplines than two years ago and expect to be involved in even more in the next two years.

Andrew Morris cautions readers to beware when you see one of these made-in-China (shocking, isn't it?) mini-drills as engineers made some bad trade-offs in the design.

"I see many of these things at flea markets and garage sales. Highly useful for PC work, but I think people buy them and then are disappointed with their performance. The motor screams at high RPM unloaded and the small 9 or 12 volt AC adapter is almost useless. It is so underpowered that the drill motor slows to a crawl, not to mention that it has no speed regulation.

The whacked-out temperature controls on EE Mike Kotecki's Viking fridge were keeping things just a little too cool:

"We moved into a new, used home two years ago that had a built-in bar in the living room. (Talk about closing tactics!) Anywho, it had a very nice 15-year-old built-in “under-cabinet” Sub Zero beverage refrigerator, that, as far as I could tell from the constant hum, cost about $400/month to keep my beer and tonic cold. So, I went out shopping and soul searching for an energy-efficient replacement.

Aluminum is a wonderful, awesome material. Heat treat it properly, and you can get a strength on par with structural steel. Okay, maybe only ordinary structural steel, but you still get a two thirds savings in weight.

It's why design engineers love aluminum. Plus it won't rust.

But screw up the heat treating, and well, you get this thing called grain boundary embrittlement that's really, really bad. Cracks can form, which can lead to a complete failure of the part.

Click on the image to see detailed view of the failed zinc casting.

Rolling luggage has to be one of the greatest engineering innovations of all time, so it's a real pity that their telescoping handles are so frequently a dismal failure. On a recent trip (to India, natch) the cheaply-cast zinc parts in the handle assembly on my husband's High Sierra brand bag (above) decided to give up the ghost. First he had difficulty getting the handle to extend, which seemed like the worst luck in the world-- until he couldn't get the handle to retract again.

You try checking a 22-inch bag with an 18-inch handle sticking out of it. Talk about needing a chill pill!