Karen B. Roberts' article photos and videos courtesy of Joby Aviation, March 9, 2021

Believe it or not, fighter jets, flying cars, natural gas pipelines and plastic bottles may be more similar than you think.

So, what is in common?

One day they may be made of TuFF, a high-performance short-fiber composite material invented by the University of Delaware, which is super strong, super light and almost indestructible. It may even be a superman in the material world.

TuFF (Customized Universal Molding Material) developed by researchers at the UD Composites Center as part of the Defense Advanced Projects Agency (DARPA) Defense Science Office program has performance comparable to the best composite materials used in today's space and aerospace applications. And, according to CCM Director Jack Gillespie, the use of TuFF is beginning to take off — literally.

In 2020 alone, this one-of-a-kind material received nearly 20 million US dollars in federal funding to promote TuFF’s four projects of the National Aeronautics and Space Administration (NASA) and the U.S. Department of Energy’s Advanced Research Projects Agency (ARPA). New Application-E), Office of Naval Research (ONR) and Department of Energy (DOE).

CCM researchers are studying how to apply this core technology, which has the potential to revolutionize high-speed composite manufacturing, make future flying taxis possible (more on this in one minute), repair our country’s infrastructure and improve manufacturing capabilities Produce ultra-lightweight materials with aerospace characteristics at the cost and productivity of the automotive industry. To date, other ongoing work has received more than $15 million in funding from DARPA.

Much of the US infrastructure that links natural gas production to consumers has existed for half a century. Some of them are in urgent need of repairs, including steel pipelines that carry natural gas to factories and homes. Current repair methods include digging and replacing aging pipes, which is an expensive and time-consuming process.

CCM researchers are designing a method to use TuFF as an internal wrapper to quickly repair existing natural gas pipelines and have received $5.9 million in ARPA-E funding. The proposed method involves constructing a composite pipe inner tube without shutting down the gas service. It will avoid the costly downtime services required by other maintenance technologies and reduce the huge social costs of bringing a faulty system back online.

The method involves using a robot to lay the composite TuFF material inside the pipeline, using an existing steel pipe as a mold, and then using ultraviolet rays to cure the material in place while the robot moves. This unique method will expand the distance that can be repaired at any time, because there is no need to close the pipeline while the robot is working.

Gillespie explained: "The outer metal pipe may rust, leaving a structurally and functionally intact composite pipe in place."

So, how will this work?

Well, full disclosure: robots don't exist yet. The CCM team is actually building robots and designing and testing the sensors, imaging technology, and integrated systems needed for the job.

When in use, the first robot will enter the pipeline, scan and digitize the specific geometry of the pipeline one part at a time, and send this information to the second robot, ready to follow and lay the TuFF resin impregnated short fiber material to the existing Tube. Because it is stretchable, TuFF will conform to complex pipe geometries and can be compressed to remove potential material defects, resulting in high-quality materials and material properties. The new TuFF pipe will be cured under an ultraviolet lamp attached to the rear of the robot, eliminating the need to use high temperatures to harden the material and ensure overall process safety.

"These pipes have very long cylindrical pipe sections, but you may have joints, curves or places with reduced pipe diameters. This is where TuFF really shines because it can stretch and adapt to irregular shapes. This is other current methods. Unachievable," Gillespie said.

Since the most popular jetpack family in the United States was broadcast on TV in 1962, flying cars have been considered a science fiction fantasy. But-due to the development of TuFF-Jetsons' preferred mode of transportation may soon become a reality.

However, in order to take off and land vertically in urban areas, flying taxis will require ultra-light materials commonly used in aerospace applications. One obstacle to this emerging urban air traffic market-kryptonite, so to speak-is that there is currently no suitable continuous fiber manufacturing process to handle the production of aviation-grade hardware at the speed and cost of other automotive parts. The only similarity is the process of injection molding automotive parts such as dashboards, knobs and intake manifolds. However, these injection molded parts are heavy and have poor material properties, which is unacceptable for flying taxis with electric and ultra-light composite bodies.

"What they need is a material that has aerospace performance but can be molded at car speed. There is no process in the world that allows you to achieve this productivity. NASA thinks this is a problem-CCM knows they have the perfect solution-TuFF ," Gillespie said.

TuFF materials provide properties equivalent to their currently available composite counterparts. TuFF material can also control the direction and characteristics of the fiber for design and optimization, but it can be stamped into complex geometric parts in a few minutes like metal. Since it can be made of any fiber and any resin, TuFF opens the door to exploring various materials and material combinations.

CCM researchers are currently focusing on developing modeling and simulation tools to design materials, manufacturing processes, and parts using TuFF materials through a $5.9 million project fund from the NASA University Leadership Program. The project, led by Gillespie at UD, utilizes CCM's 9,000-square-foot TuFF comprehensive pilot manufacturing facility, including collaboration with industry partners Joby Aviation and Spirit AeroSystems, Advanced Thermoplastics Composites Manufacturing, and colleagues from Southern University in Baton Rouge, Louisiana.

So, where are you looking for ideas to expand on things you haven't done before? Gillespie said that CCM is approaching non-traditional manufacturing, such as non-woven paper, seeking solutions that they can adapt to.

Although the industry is very different, both paper and TuFF are materials composed of many short fibers, which are pressed together with an added binder. The difference is that TuFF composites are made by using short structural fibers and aligning them perfectly.

Gillespie and others at CCM are considering ways to adjust the composite paper production framework by adding plug-in modules to the fiber alignment process. The result is that the material can be manufactured at a fraction of the current cost, and the productivity is high enough to be expanded for different markets. Although this method requires water resources, the water itself can be recycled, making the process green.

In another project that received ONR funding of US$5.4 million, CCM researchers are working with Arkema to combine TuFF technology with high-performance thermoplastics to manufacture small metals in a safe, more affordable, repeatable and scalable way Aircraft parts. This project extends CCM's ongoing DARPA work to advance lightweight materials technology for military platforms such as fighter jets.

CCM researchers are also exploring ways to reuse recycled composite fiber. In one project, researchers are cutting obsolete aircraft parts into short fibers and then recombining them to make the same material (or better material) again.

Gillespie said that with TuFF, it is possible to re-decompose products that are about to end their material life into their components, rearrange the carbon fiber and make the same material, with the same characteristics and the same-or better-value, and better handling. Ability and the ability to manufacture complex geometrical parts with huge cost savings. From an energy point of view, the implied energy cost of a material is significantly reduced during its service life.

"This may mean providing quality materials at a fraction of the cost," he said. "This will greatly reduce the cost of the manufacturing process because it can be stamped and formed like metal, rather than hand-formed, for aircraft and spacecraft applications. Therefore, we can complete it in a few minutes instead of spending a month. Make parts."

In another project, CCM researchers will apply the same technology to the challenge of plastic waste, and recently received $2.49 million as part of the DOE BOTTLE Consortium (Bio-Optimization Technology to Keep Thermoplastics away from Landfills and the Environment). Here, the research team plans to use polymers from recycled plastic bottles or other bio-based polymers to upgrade short recycled structural fibers to make TuFF composites, thereby increasing the value of these two materials.

This is a game changer, as recycling usually involves downgraded recycling of materials used in low-value applications, such as park benches.

Gillespie called TuFF a "great success story" for research funded by UD and the federal government because all these new projects are derived from a core technology (TuFF) that was developed through high-risk, high-return research funded by DARPA in 2016 of. This is also a good example of interdisciplinary cooperation, as the project includes contributions from researchers with expertise in mechanical engineering, materials science and engineering, civil engineering, electrical and computer engineering, and CCM professionals.

And CCM researchers are just getting started.

"If you put them together, we can create materials that are ten times cheaper than existing materials for all these applications-all without sacrificing performance," he said. "So, when I talk about changing the paradigm of the world's composite materials and taking over the world market, I'm serious."

Articles by Karen B. Roberts

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