Posts tagged ‘engineering’
Boiling and brittle
December 23rd, 2011 at 4:58 pm by Dr. Drang
I had to finish breaking some plastic yesterday. A client had sent me some polycarbonate parts that were cracking in service and wanted to know why. This is the sort of thing I do when I’m not writing shell scripts—it pays better. Normally, when you have a broken part, you can look at the broken…
Let’s twist again
September 29th, 2011 at 1:30 pm by Dr. Drang
Sunday night, my wife and I heard a muffled bang that seemed to be coming from our garage. Expecting to find that a shovel had fallen off the wall rack and into my car, I went out to take a look. Nothing. Maybe the noise came from outside? I pushed the garage door button to…
Coffee, tea, and Joulies
August 16th, 2011 at 8:41 am by Dr. Drang
I really liked Marco Arment’s post last week on how he tested his first set of Coffee Joulies. Joulies are the little bean-shaped things that are supposed to cool your coffee quickly to the optimal drinking temperature and keep it there for a long time. Their manufacture was funded by a very successful Kickstarter project…
Condiment container engineering
July 15th, 2011 at 8:01 pm by Dr. Drang
We’re in the middle of prime cookout season, and I’ve been fighting with ketchup and mustard bottles. When I was a kid, fighting with ketchup bottles was commonplace. The bottles were glass, and if the bottle was full enough and the ketchup thick enough, it took a long time—and maybe a few good whacks on…
Southwest 812
April 25th, 2011 at 11:41 pm by Dr. Drang
The National Transportation Safety Board put out a press release today, summarizing its initial findings in the investigation of Southwest Flight 812. That was the flight that had make an emergency landing a few weeks ago because a five foot long hole ripped through its fuselage during a flight. It’s a very well written summary—better,…
Cracked
April 6th, 2011 at 12:50 pm by Dr. Drang
Hey, there’s something in the news that I actually know a good deal about! The roof failure on Southwest Flight 812 is being blamed on fatigue, which is the fracture of a part under repeated loadings. Fatigue is one of those words, like stress and strain, that engineers have appropriated from everyday use and given…
Soil liquefaction
March 11th, 2011 at 9:33 am by Dr. Drang
Several days ago, Cory Doctorow posted this video on Boing Boing. It’s a cute demonstration of soil liquefaction in a wheelbarrow. Not so cute is what soil liquefaction can do. The maker of the video got the soil from his garden in Christchurch, New Zealand, where last month’s earthquake did a lot of damage through…
Balls
February 28th, 2011 at 8:45 am by Dr. Drang
It’s never been my goal to become America’s most beloved shower curtain blogger, but we go where our talents lead us. I’m staying at a Radisson with one of those nice outward-bowing curtain rods and I noticed a slight design variation. The variation isn’t in the rod but in the curtain hooks. These have four…
Oil canning and coffee makers
February 24th, 2011 at 7:26 am by Dr. Drang
Electric drip coffee makers for the home got popular in the ’70s. The Engineer Guy, Bill Hammack, has a nice video describing how the pump works. In this post, I’m going to talk about the engineering behind another part of the coffeemaker, the hot plate that keeps the carafe warm. In the process, we’ll revisit…
Oil can what?
February 12th, 2011 at 3:38 pm by Dr. Drang
I’ve been working on a nonlinear finite element program for the past week or so, and to shake out the bugs, I run it on a few test problems. One of my favorites is an example of snap-through buckling. It’s a simple little toggle structure with surprisingly rich behavior. The toggle looks like this: Two…
