New method to test materials can aid national defense


March 19, 2013

A report on research exploring ways to characterize the internal structure, properties and behavior of advanced materials used in challenging Department of Defense operations has won three Arizona State University engineers the 2012 Best Paper Award from the Journal of Aerospace Engineering.

The paper’s co-authors are professor Aditi Chattopadhyay, assistant research professor Masoud Yekani Fard and assistant research scientist Yingtao Liu. Each is on the faculty of the School for Engineering of Matter, Transport and Energy, one of ASU’s Ira A. Fulton Schools of Engineering. Aditi and Masoud materials research Download Full Image

The award will be formally presented to Chattopadhyay at the next Earth and Space Conference organized by the Aerospace Division of the American Society of Civil Engineers.

The winning paper, "Analytical Solution for Flexural Response of Epoxy Resin Materials," is based on a chapter of Yekani Fard’s doctoral thesis on a three-year project funded by the Army Research Office involving studies of the high-velocity impact resistance of composite materials.

The Army is interested in specific applications of the materials research for aircraft and aerospace systems, weapons and defense systems, and ground transportation resources that would be exposed to high-impact situations on the battlefield. The same kinds of composite materials are also commonly used in bridges and tunnels, and in marine and offshore structures, as well as in automobile bumpers and panels, and in consumer products such as tennis racquets. 

The researchers are looking at how the various material components in the composites behave to better understand how the materials will hold up under high- impact pressures.

"The Army is using composites in mission-critical systems," Chattopadhyay says. “They need to know if a material is strong enough to withstand the sort of impact it is expected to go through." That requires a focus on the epoxies that essentially are the “glue” that holds together the various materials in a composite.

"In most of the applications, it is the epoxy that is the dominant factor in the behavior of the whole structure," Yekani Fard explains.

The leading method to predict epoxy resin behavior has been an empirical approach called the Weibull model. The researchers say the effectiveness of the model depends entirely on conducting a high number of experiments, and the method has a significant margin of error.

These factors make the Weibull model not only expensive and inaccurate to a certain degree, but it cannot be applied universally to different epoxy resins, and instead must be repeated for the assessment of each individual material.

The inefficiency of the Weibull model and the prevalent use of epoxy resin in composites creates a strong need for accurate understanding of the behavior under variable loading, or changing pressure and stress. The team’s award-winning paper details development of a new modeling method to produce a more reliable prediction of the capabilities of various epoxy resins.

The team developed an approach that can be applied not only to all epoxy resins, but to multiple semi-brittle materials. The method uses basic physics concepts of push-and-pull deformations in and out of a material plane, and classifies the similarities and differences in the material's response.

"We were able to develop a methodology with formulations that are extensive, but the fundamentals are simple physics, which allows use in different applications," Yekani Fard says.

The new method, for instance, allows for more reliable testing to predict the behavior and strength of materials such as bone cements – substances commonly used to hold implants in bone in procedures such as hip replacement and knee replacement surgeries. The composites that make up such cements contain semi-brittle materials similar to the materials used in military applications.

The Army Research Office also funded a series of experiments to gather data and research literature used to develop the model. Once the model was developed, it was tested for accuracy on different types of structures.

"This model adds to the knowledge of scientists and engineers in understanding how a material behaves both fundamentally and in different types of structures," Yekani Fard says.

Joe Kullman

Science writer, Ira A. Fulton Schools of Engineering

480-965-8122

ASU community invited to take part in accreditation review process


March 19, 2013

Faculty, staff and students across ASU will have the opportunity this month to voice their ideas about ASU at special forums held on all four campuses. These forums are part of the decennial review of the institution’s accreditation by the North Central Association’s Higher Learning Commission (HLC).

Among other benefits to ASU, the accreditation certifies that the academic programs of ASU are suitable for federal financial aid, and that the university has the capacity to advance the quality of those programs. All ASU academic programs are covered by the HLC accreditation. Download Full Image

The goal of the review process is to establish how ASU meets HLC’s Criteria for Accreditation. As part of the preparation for this review, a university task force formed from across ASU’s four campuses developed a Self-Study Report over the past 45 months that documents the evidence that the institution meets the HLC criteria. More information on the process and access to the Self-Study Report are available at http://hlc2013.asu.edu.

The effort culminates this month with a comprehensive site visit on March 25-27.

Fifteen site visit team members from across the country will come to ASU to meet with key leaders and representatives of all operational areas of the institution, including academic programs, student and faculty quality, student services, budget and planning operations, ethical practices, and many other areas.

To help inform the site visit team about ideas and concerns from the ASU community, members of the site visit team will hold separate forums on Monday, March 25 for faculty members, staff employees and students on each of the four campuses.

These forums will be held on the Downtown, Polytechnic and West campuses with the following schedule:

Open faculty forum: 1:30-2:15 p.m.

Open staff forum: 2:45-3:30 p.m.

Open student forum: 3:30-4:15 p.m.

On the Tempe campus, the forum schedule will be:

Open faculty forum: 2:15-3 p.m.

Open staff forum: 3-3:45 p.m.    

Open student forum: 3:45-4:30 p.m.

The four campus venues are:

Downtown Phoenix: Cronkite 444

Polytechnic: Cooley Ballroom B

Tempe: Carson Ballroom, Old Main

West: La Sala, UCB

"This input from the ASU community is vitally important to the accreditation review, so the team has made arrangements to be available on every campus to hear comments, suggestions and concerns,” said Barry Ritchie, vice provost for academic personnel and director of the university accreditation task force.

Following the March visit, the site visit team will report to HLC on whether ASU meets the standards required to continue its accreditation. The HLC will then act on that recommendation later this year.

Britt Lewis

Communications Specialist, ASU Library