There seems to be a rush to judgment to find the flaws that caused the I-35W bridge to collapse in Minneapolis. The new theory—faulty steel gusset plates—strikes me as grasping at straws. Why after 40 years would faulty plates suddenly result in a catastrophic failure? Why has this never been raised before as a potential flaw in this type of bridge? As MIT metallurgist Ken Russell pointed out here recently, steel is made in huge batches, and its chemistry is carefully tested. Suddenly we discovered that this ancient batch was a bad one? Or that the designer used a wrong gauge or grade of steel?
It probably will take months for a meaningful analysis of the bridge failure to emerge. Undoubtedly, the investigators will find a frightening list of contributors to the collapse, starting with the corroded steel roller bearings already reported as deficient in 1990.
HP revealed more of its 3D printing plans in a recent webinar. Senior vice president of inkjet and graphics solution business Stephen Nigro spoke about how the technology works and expanded on HP's vision of open collaboration to commercialize its Multi Jet Fusion 3D printing technology for end-production, and open collaboration on new materials. He also said HP will create software to help users decide when to use Multi Jet Fusion versus conventional subtractive manufacturing.
A lightweight electric urban concept car designed by several European companies weighs only 992 lb without its battery. It would have weighed 26.7 lb more if its windows were made of glass instead of the specially coated LEXAN polycarbonate resin from SABIC Innovative Plastics.
Skylar Tibbits' team in MIT's Self-Assembly Lab is now 4D printing self-assembling shapes made of programmable carbon composites and custom wood grain. The composites are being used in a sport car airfoil, and the wood grain is beautiful.
The NanoSteel Company has produced high-hardness ferrous metal matrix composite (MMC) parts using a new nanosteel powder in a one-step 3D-printing process. Parts are 99.9% dense, crack-free, and with wear resistance comparable to M2 tool steels.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.