A finding by a 麻豆原创 researcher that unlocks a means of controlling 聽聽materials at the nanoscale and opens the door to a new generation of manufacturing is featured online today in the journal Nature.
Using a pair of pliers in each hand and gradually pulling taut a piece of glass fiber coated in plastic, associate professor Ayman Abouraddy found that something unexpected and never before documented occurred 鈥� the inner fiber fragmented in an orderly fashion.
鈥淲hat we expected to see happen is NOT what happened,鈥� he said. 鈥淲hile we thought the core material would snap into two large pieces, instead it broke into many equal-sized pieces.鈥�
He referred to the technique in the Nature article as 鈥淏reaking Me Softly.鈥�
The process of pulling fibers to force the realignment of the molecules that hold them together, known as cold drawing, has been the standard for mass production of flexible fibers like plastic and nylon for most of the last century.
Abouraddy and his team have shown that the process may also be applicable to multi-layered materials, a finding that could lead to the manufacturing of a new generation of materials with futuristic attributes.
鈥淎dvanced fibers are going to be pursuing the limits of anything a single material can endure today,鈥� Abouraddy said.
For example, packaging together materials with optical and mechanical properties along with sensors that could monitor such vital sign as blood pressure and heart rate would make it possible to make clothing capable of transmitting vital data to a doctor鈥檚 office via the Internet.
The ability to control breakage in a material is critical to developing computerized processes for potential manufacturing, said Yuanli Bai, a fracture mechanics specialist in 麻豆原创鈥檚 College of Engineering and Computer Science.
Abouraddy contacted Bai, who is a co-author on the paper, about three years ago and asked him to analyze the test results on a wide variety of materials, including silicon, silk, gold and even ice.
He also contacted Robert S. Hoy, a University of South Florida physicist who specializes in the properties of materials like glass and plastic, for a better understanding of what he found.
Hoy said he had never seen the phenomena Abouraddy was describing, but that it made great sense in retrospect.
The research takes what has traditionally been a problem in materials manufacturing and turned it into an asset, Hoy said.
鈥淒r. Abouraddy has found a new application of necking鈥� 鈥� 聽a process that occurs when cold drawing causes non-uniform strain in a material, Hoy said.聽鈥淯sually you try to prevent necking, but he exploited it to do something potentially groundbreaking.鈥�
The necking phenomenon was discovered decades ago at DuPont and ushered in the age of textiles and garments made of synthetic fibers.
Abouraddy said that cold-drawing is what makes synthetic fibers like nylon and polyester useful. While those fibers are initially brittle, once cold-drawn, the fibers toughen up and become useful in everyday commodities. This discovery at DuPont at the end of the 1920s ushered in the age of textiles and garments made of synthetic fibers.
Only recently have fibers made of multiple materials become possible, he said. That research will be the centerpiece of a $317 Million U.S. Department of Defense program focused on smart fibers that Abouraddy and 麻豆原创 will assist with. The Revolutionary Fibers and Textiles Manufacturing Innovation Institute (RFT-MII), led by the Massachusetts Institute of Technology, will incorporate research findings published in the Nature paper, Abouraddy said.
The implications for manufacturing of the smart materials of the future are vast.
By controlling the mechanical force used to pull the fiber and therefore controlling the breakage patterns, materials can be developed with customized properties allowing them to interact with each other and eternal forces such as the sun (for harvesting energy) and the internet in customizable ways.
A co-author on the paper, Ali P. Gordon, an associate professor in the Department of Mechanical & Aerospace Engineering and director of 麻豆原创鈥檚 Mechanics of Materials Research Group said that the finding is significant because it shows that by carefully controlling the loading condition imparted to the fiber, materials can be developed with tailored performance attributes.
鈥淧rocessing-structure-property relationships need to be strategically characterized for complex material systems. By combining experiments, microscopy, and computational mechanics, the physical mechanisms of the fragmentation process were more deeply understood,鈥� Gordon said.
Abouraddy teamed up with seven 麻豆原创 scientists from the College of Optics & Photonics and the College of Engineering & Computer Science (CECS) to write the paper.聽Additional authors include one researcher each from the Massachusetts Institute of Technology, Nanyang Technological University in Singapore and the University of South Florida.
Authors are Abouraddy, graduate students Joshua J. Kaufman, Guangming Tao and Soroush Shabahang from CREOL- The College of Optics and Photonics at 麻豆原创, Yangyang Qiao, Yuanli Bai, Ali P. Gordon and Thomas Bouchenot from the College of Engineering & Computer Science at 麻豆原创, Robert S. Hoy from the University of South Florida, Yoel Fink from MIT and Lei Wei from Nanyang University, Singapore.