Tech Briefs - Tech Briefs

1. Generative Design Pairs with Digital Manufacturing for Space-Ready Parts

   NASA engineers partnered with digital manufacturer Protolabs for a generative design experiment at the recent PowerSource Global Summit, a technology conference held in Orlando.

   The goal of the experiment was to promote the game-changing role generative design can play in accelerating innovation. Attendees would work with NASA engineers to utilize the AI-driven tool in the creation of a space-ready part from scratch, followed by quick-turn digital manufacturing delivering the generatively designed part to the conference 36 hours later.

   NASA engineers challenged attendees to generatively design an apparatus capable of withstanding a trip to the moon with a function to help advance the Artemis mission and its goal to explore the moon in preparation for life on another planet. The part would secure a 250mL container that collects volatile compounds released after sunrise on the surface of the moon.

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   NASA and conference attendees jointly developed a list of geometries and qualities the apparatus would need to survive the flight and tolerate the moon’s extreme conditions. For example, the part would need to function in a wide temperature range. At sunrise, the temperature increases dramatically from -315 °F to -55 °F (-193 °C to -48 °C). Conference engineers developed parameters by analyzing the function of the part and the environment it would need to function in.

   From a mass perspective, the part could not weigh more than 68 pounds. NASA stats indicate that it costs $1 million for every kilogram (2.2 pounds) launched into space. A material like Aluminum 6061 was an ideal choice due to its outstanding strength-to-weight ratio. The size of the part was also a factor with the limited capacity on a spacecraft. The group ensured the part would be modular, so it could be separated into two parts and compactly stackable. Finally, the volume of each component was restricted to about the size of a shoebox.

   Durability was also an important consideration, particularly during the launch of the spacecraft. To make certain the apparatus survives, a parameter was set stating the part’s base modal frequency would exceed 100Hz.

   Once on the moon, the group determined the apparatus’ footings would have to provide stability on the moon’s uneven surfaces. A final parameter aimed to use the moon’s extreme cold temperatures to provide stability once the two components are stacked to form the apparatus. The upper portion would feature feet that bind when cooled, which was proven out in a thermal stress analysis.

   Following the presentation, NASA engineers loaded the parameters into its generative design software, producing a part that outperformed expectations. In recent history, parts designed via generative often average a 6 to 10 times improvement in mass, stiffness, and overall design time.

   “The awesome thing about it is that we didn’t know what we were going to make in the end,” said Matthew Vaerewyck, Mechanical Engineer at NASA Goddard Space Flight Center.

   In addition to the conditions necessary to survive and perform the task on the moon, NASA’s generative design process factors in design-for-manufacturability. Informed by Protolabs’ toolpathing instructions, the AI-driven design tool ensured the part could be machined using only two axes to minimize the overall machining minutes required. Tweaks like the breaks in the apparatus’ circular design improved accessibility for the end mills as they moved along X- and Y-axes.

   “For this event to be successful, we knew that any manufacturer we went with [to make the part], needed to deliver the part we ordered on time. There was no room for error or delay,” said Vaerewyck. Digital manufacturing, with its ability to produce and ship parts in as fast as a day, has been a logical partner in NASA’s focus on quick-turn iteration.

   Vaerewyck and his team uploaded the CAD file to Protolabs digital quoting platform that evening, less than 10 hours after the original crowdsourcing experiment. Soon after, the Aluminum 6061 block was loaded into a CNC machine at Protolabs’ facility in Brooklyn Park, Minn. Automated toolpathing software along with input from Protolabs engineers identified an efficient 19 hours of machining time followed by four hours of processing.

   The part was complete and ready for shipping at 4:31 p.m. the next day and immediately sent off for overnight delivery. The part travelled from Minnesota to Florida, arriving before the doors opened on the final day of the conference — just 36 hours after the CAD file was uploaded for manufacturing.

   NASA was able to showcase the part to the attendees responsible for generatively designing it, even showing its effectiveness using a dry ice demonstration as an example of its vapor-capturing abilities.

   This article was written by Dan Snetselaar, CNC Product Lead, Protolabs (Maple Plain, MN). For more information, visit here.

2. A Shape-Shifting Metamaterial Inspired by Push Puppets

   Inside a push puppet, there are connecting cords that, when pulled taught, will make the toy stand stiff. But by loosening these cords, the “limbs” of the toy will go limp. Using the same cord tension-based principle that controls a puppet, UCLA researchers have developed a new type of metamaterial, a material engineered to possess properties with applications for soft robotics, reconfigurable architectures, and space engineering.

3. Butterfly-Inspired AI Technology
   Tech Briefs: What started you thinking about butterflies and AI?

   Saptarshi Das: In general, our research is toward smart electronic devices. You need to make them low power because AI consumes a huge amount of energy and that can very soon become unsustainable. So, one of the major thrusts in our research is to develop sustainable electronic devices, many of which are smart sensors that do computing at the edge — close to what they are sensing rather than at a server or in the cloud. So, our challenge is to make them as energy efficient as possible.

4. How Much Do You Know About MOSA?

   In 2019, the U.S. Department of Defense (DoD) adopted a new federally mandated acquisition policy for new technologies known as the Modular Open Systems Approach (MOSA). The Defense Department describes MOSA as a technical business strategy for designing an affordable open architecture system that can be easily upgraded with new capabilities.

5. Force Testing Profile Stings

   The L.S. Starrett Company
   Athol, MA
   www.starrettmetrology.com

   A group of graduate students from Cal (California) State Fullerton was conducting research in the field of ground vehicle aerodynamics to test the structural capacity of custom profile stings during high-threshold testing in a wind tunnel. The stings were mounted to the top face of the wind tunnel and used to consolidate cabling and actuating rods for a kinematic system. The system served to propagate a test vehicle model in six degrees of freedom where the stings were subjected to forces being applied to the leading edge, perpendicular to its length. The stings were made from 3D-printed material with wall thicknesses of 0.03" (0.8 mm), 0.04" (1.0 mm), and 0.05" (1.3 mm).