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.
This grab-bag of new fasteners and adhesives work with a range of materials they can attach to, as well as a wide variety of applications. Several are for use in consumer applications, such as wearables or other compact electronic assemblies, and some of the adhesives have extended service temperature ranges and cure at room temperature.
Several of the new and noteworthy 3D printers in this slideshow are breaking some boundaries in build volume, new metals printing techniques, or working with high-profile development partners to ensure very high-quality parts and controls.
United Launch Alliance will fly 3D-printed flight hardeware parts on its rockets starting next year with the Atlas V. The company's Vulcan next-gen launch vehicle will have more than 100 production parts made with 3D printing. The main driver? Parts consolidation and 57% lower production costs.
A new report from the National Institute of Standards and Technology (NIST) makes a start on developing control schemes, process measurements, and modeling and simulation methods for powder bed fusion additive manufacturing.
Although bio-based polymers face challenges from petroleum-based polymers, in certain markets they can displace the petro-based incumbents. Here are six new bio-based and renewable plastics for a variety of applications.
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