Vol. 17, No. 10	Nov. 6, 1997

Composites project gets $1.4M U.S. Navy grant

A team of researchers from the University of Delaware Center for Composite Materials (CCM) and Department of Mechanical Engineering has been awarded a $1.4 million grant over 15 months from the Office of Naval Research (ONR) to establish an Advanced Materials Intelligent Processing Center (AMIPC).

Led by Karl V. Steiner, executive director of CCM and adjunct professor of mechanical engineering, and Suresh G. Advani, professor of mechanical engineering, the program will focus on low-cost liquid molding technologies for manufacturing composites. In addition to UD, the team includes industrial and government partners.

In announcing the grant, Provost Mel Schiavelli said, "Government programs-complemented by collaborations with industry-are a vital part of the research conducted within our College of Engineering. I'm delighted to see the initiation of this new activity with the Office of Naval Research aimed at reducing the cost of advanced materials through intelligent processing, and I'm pleased that this center continues a tradition of close collaboration with industry."

Northwestern University was a heavy contender for this grant, said U.S. Sen. Joseph R. Biden Jr., who led the congressional effort to direct these funds to the University of Delaware. But, he said, "the Pentagon knew we could do the better job. That's why the University and this composite center got the grant, based on its track record. Awarding this grant to the University of Delaware's Center for Composite Materials is another vote of confidence in the world-class, cutting-edge technology for manufacturing composites being researched and developed right here in our state. In fact, over the last eight years, this center has been awarded nearly $14.5 million in U.S. Defense Department grants and contracts, and I am proud such a nationally respected center is based at my college alma mater."

"Senator, I think you have a right to be proud of your alma mater," James Kelly, AMPIC program manager for the Office of Naval Research, said. He said the Navy is looking to AMPIC to produce and improve composite technology in many areas. He was especially enthusiastic about resin transfer molding, a technology that has been used to mask and protect the surface of ships. "The products from this program will influence the future," Kelly said.

Resin transfer molding and other liquid molding processes generally involve the injection or infusion of resin into a textile preform- essentially a braided or woven fibrous skeleton of the part to be made.

"Intelligent processing of composites via these technologies will lead to reduced cost and improved part quality," Steiner said. "The program will be driven by ONR's need for sophisticated process control or intelligent processing-in other words, processes that proceed very rapidly and without constant human inspection or intervention."

The program will have three major components: virtual manufacturing, lab-scale validation and prototype development. Virtual manufacturing, defined as an integrated, synthetic manufacturing environment created to enhance all levels of decision and control, involves the use of computer simulations to enable the ideal pro-cessing parameters to be identified.

Advani's research team has developed and refined a computer-aided mold design tool known as LIMS (Liquid Injection Molding Simulation). "LIMS allows us to monitor and predict the effect of such variables as mold-wall tempera-ture, resin temperature and the location of resin inlet and exit gates on the quality of a composite part without actually making expensive prototype molds and extensive production runs," Advani said.

The tool, which is already used by a number of companies and government labs affiliated with CCM, will provide the foundation for the virtual manufacturing phase. LIMS will continue to be updated with the results of new research, and "virtual sensors" will be implemented in the simulation to identify such processing challenges as dry spots (areas where the resin does not penetrate) and racetracking (areas where the resin flows more rapidly).

"From the virtual manufacturing environment, we'll have a good understanding of the location of injection gates and vents, the placement of sensors, and the control strategies that we should employ to minimize processing time while maximizing part quality," Advani said. "This information will then be used in the next phase, where we'll work with industry to develop a lab-scale validation set-up at CCM. Here, Honeywell will provide expertise on the development of process control strategies. At this point, we will have evolved from virtual manufacturing to actual manufacturing but still within the laboratory setting."

The lab-scale validation stage will include evaluation and integration of a number of on-line sensors, such as fluorescent spectroscopy and infrared thermography, for detecting manufacturing-induced flaws.

Previous research at CCM has shown that thermography techniques can be used to detect void regions and other inhomogeneous regions in composite structures. "Thermal imaging has high potential for use as external sensor for the RTM process by enabling full-field imaging of the mold-filling stage," Steiner said. "In the next stage, the IR camera can be used to track the heat emitted by the resin during the cure cycle. Overall, a major advantage of IR thermography as a candidate on-line sensor is that it doesn't require direct contact with the surface or a position normal to the surface."

The third phase of the program, the lab-scale intelligent manufacturing cell developed at UD will be scaled up for the manufacture of an actual prototype part at the facilities of the Boeing Co. in St. Louis, with hardware support from Honeywell.

"To facilitate technology transfer and implementation, Honeywell and Boeing will work with us in developing our lab-scale manufacturing cell at UD," Steiner said. Other UD mechanical engineering faculty participating in the project include Tsu-Wei Chou, Jerzy L. Nowinski Professor, and Jian Q. Sun, assistant professor. Chou will lend his expertise in the area of textile preforms, while Sun will contribute in the process controls area.

As part of this effort, a national conference will be organized together with the Manufacturing Technology Information Analysis Center (MTIAC) and held in Delaware early next year to provide a forum for addressing issues in the intelligent processing of composites.

-Diane Kukich and Barbara Garrison
Photo by Jack Buxbaum