What’s new?
Researchers at the US National Institute of Standards and Technology (NIST) have added a fluorescent material to fiber reinforced plastics to enable the detection of damage to the material over time.
What does it mean?
Fiber reinforced plastics are one type of composite material increasingly used to make lightweight strong components, such as airplane, automobile, boat, and building components. Fibers (carbon and glass are commonly used) are embedded in a plastic material, called a matrix, sometimes with the fibers aligned to add strength.
While such composites offer many benefits, they can deteriorate over time as the matrix and embedded fibers separate. In a 2005 incident, the rudder on an Airbus 310 broke off during a flight due to such separation. The pilots were able to recover control of the plane and land successfully with no injuries to occupants. Visual inspection had not detected any problem with the rudder. Other issues may have been involved in this incident, including a change in the sensitivity of the control system and possible aggressive use of the rudder by the pilot.
The NIST researchers have added small molecules, called mechanophores, that fluoresce after the impact of mechanical force such as what occurs when tiny cracks appear between the fiber and matrix. Fiber reinforced plastics with mechanophores can then be easily scanned for interior cracks. NIST cites the possible use in detecting cracks in wind turbine blades.
What does it mean for you?
The new technology highlights progress in materials, trends toward embedded sensors, and the always present need to consider the people in the system.
All engineered materials are composites. Consider concrete, made from cement which is “manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients”, then mixed with water and other materials, and cured into a hard, rock like substance which humans have used for thousands of years. Useful metals (steel, aluminum, cast iron) are all alloys, with different alloys in different quantities yielding metal alloys with different useful properties. Even a wood I beam is an engineered product, with solid sawn lumber joined to board made by using adhesives and compression to solidify layers of wood strands. Progress in almost every field of technology depends on advances in materials. Increasingly physics and chemistry are supplemented by biology, for example in organic photovoltaics, hemp reinforced plastics, and organic-inorganic composites in biomedical applications. Advances in the science and engineering of composites are improving the technology that will enable decarbonization of the economy through renewable energy for generation of electricity and through improved energy storage.
In automobiles, the transition from carburetor to fuel injection, the addition of emission controls, and improvements to occupant comfort all rely on the ubiquity of sensors and computation. The Internet of Things and Industry 4.0 incorporate the exchange of data and the increasing use of computation, but the first requirement is always sensors to collect the data. Sensors can measure light, heat, pressure, motion, sound, moisture, magnetic field, and in fact almost any physical property. Sensors can replace, literally, the canary in the mine to keep people safe underground and remote sensing from a satellite in space can be used to assess crops on earth.
No matter what field your organization is in, I guarantee that new materials and increasing use of sensors is affecting and will continue to affect your field. Many advise consumers not to buy the first year of a redesigned car and an issue with new technology is to find that sweet spot between being the early adopter (said to be at the bleeding edge) and being the laggard. I tend to be a late adopter (I was the last person I knew to buy a microwave), but you need to think about the technology strategy for your organization. What are the key types of technology that drive your organization? Who is monitoring the environment for new advances in that technology?
Finally, some evidence in the Airbus 310 incident indicates that pilots had not be told enough about changes to the rudder and potential interactions with how the pilot might use the rudder. The application of radar in World War II is a well known story about how technology supported war efforts, but less well known is the role of operations research in improving the use of radar by improving the operators’ techniques. Any technology is part of a system of technology and human; the use of the technology by the humans can amplify or undermine the usefulness of the technology.
Where can you learn more?
The report by NIST is here.
Mostly we engineers are going to take care of these developments for you. Scientists and engineers working on new materials publish in many journals. The NIST researchers published their work in the journal Composites Science and Technology. Recently published articles in that journal covered topics such as the behavior of 3D braided composites at high temperatures, prediction of the fatigue life of a specific type of laminates, and methods to improve the strength of the interfaces of carbon fiber-epoxy composites.
You can track the implications for your field through your own professional associations by making sure your organization monitors new products, through industry publications and meetings. I love learning about these new developments, so for over 50 years, I have read New Scientist, a weekly magazine with mostly very short articles on developments in all fields of science and technology. For example, an April article describes the use of vanadium dioxide, with added tungsten, printed in a grating to make smart windows that adjust to control how much light is emitted during the day. Blocking heat from near-infrared light reduces the cooling needs of building fitted with such windows.