Fasteners—usually the less glamorous part of a mechanical design—have been grabbing headlines lately. First it was a lack of fasteners that created (or was at least blamed for) the first delay announcement for the Boeing Dreamliner. Now two metallurgists have put out a book that really dredges up the past. In “What Really Sank the Titanic” , coauthors Jennifer Hooper McCarty and Tim Foecke say that substandard rivets were responsible for the rapid descent of the supposedly unsinkable vessel. Metallurgical testing of 48 rivets recovered from the Titanic showed that slag concentrations were at 9 percent, six or seven percent higher than they should have been. Slag is a brittle byproduct of the iron making process. Design engineers put the weaker rivets in areas expected to see less stress, such as the bow. Unfortunately, that is right where the Titanic scraped an iceberg. McCarty and Foecke postulate that fewer compartments would have burst if better rivets had been used. It’s possible, they say, that the Titanic could even have limped into Halifax. They also suggest that the bad rivets may have resulted from a rush to get the boat built at a time when rivets were in tight supply.
A self-propelled robot developed by a team of researchers headed by MIT promises to detect leaks quickly and accurately in gas pipelines, eliminating the likelihood of dangerous explosions. The robot may also be useful in water and petroleum pipe leak detection.
Aerojet Rocketdyne has built and successfully hot-fire tested an entire 3D-printed rocket engine. In other news, NASA's 3D-printed rocket engine injectors survived tests generating a record 20,000 pounds of thrust. Some performed equally well or better than welded parts.
Researchers at MIT's d'Arbeloff Laboratory are developing shoulder- and hip-mounted robotic arms to help workers in aircraft manufacturing perform difficult or complex assembly tasks that would normally require two people.
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