The world we interact with is dominated by intertwined materials known as composites. Unlike in metal alloys or polymer blends, where the atoms or molecules are intimately mixed, components of a composite material retain their individual identities, and their careful selection and combination maximizes certain sets of properties. Here, too, another facet of composite materials emerges--they typically have stronger and weaker directions (i.e., asymmetric properties), as they are designed to fulfill the needs of specific applications. The benefits of combining materials are easily learned from nature. Natural composites such as nacre, wood, and teeth have impressive properties arising from their hierarchical structures, especially as they are generated from easily obtained starting materials that often have limited capabilities.
The US military may not seem like the greenest of organizations, but if rising seas and temperatures produce worldwide chaos, they're the ones that have to deal with that shit. Now, the Department of Defense is trying to tackle environmental problems caused by spent bullets and casings on its firing ranges by using composite materials laced with seeds. While casings are collected, and often recycled, the bullets themselves generally aren't, and can take "hundreds of years" to break down in the environment. That can pollute the soil and water supply, harm animals, and generally look like crap if you stumble upon them. To tackle the problem, the DoDo has made a proposal call for a biodegradable composite bullet impregnated with seeds that will survive the initial blast and searing velocities.
Self-healing materials are so widespread that clothes lines and tech companies are already applying them to different products. Now, a research team at the University of California, Riverside, has developed a new type of self-healing material that is conductive of electricity, highly elastic, and almost entirely transparent. The lead researcher has revealed that he drew inspiration from Marvel's Wolverine character.
Dr. Marc Schultz, NASA Langley research engineer, said the "failure still caught [them] off guard" even though they were expecting it. "The loud bang first startled us and then we saw the crack all the way around the barrel that formed almost instantaneously from the buckling event," he added. This is only the first in a series of large-scale tests for NASA's composite material. The researchers plan to apply what they learned from this round to the next four rounds planned over the next four years. NASA's primary goal is to determine a composite material and structural design that can be used to make rockets lighter and tougher than their metallic counterparts.
Researchers at US university Carnegie Mellon have created a new electrically conductive material that can repair itself, presenting new opportunities for soft robotics and wearable technology. Combining properties of metal and plastic, the supple, stretchy material can be used to make circuits that stay operational even after sustaining physical damage. The discovery opens up the possibility that robots may one day have sensor-laden skin that can repair itself like a human's, or that we could sport ultra-thin wearable devices on our bodies for long periods of time without them degrading. "This could have important applications in areas like wearable computing, where you want circuits you can incorporate into textiles or place on your skin, and just like natural skin if you get bruised or cut, your skin is able to repair itself," says Carmel Majidi, an associate professor of mechanical engineering, in a video produced by Carnegie Mellon University (CMU). "Our material also has this property."