New method to test materials can aid national defense

Mar 20, 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.

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 ," 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 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.

Explore further: Lifting the brakes on fuel efficiency

add to favorites email to friend print save as pdf

Related Stories

Carbon nanotube composites for enzymes and cosmetics

Sep 06, 2011

Japanese researchers have developed a low cost and efficient method for producing electrically conducting composites based on electrostatic adsorption of CNTs onto resin and ceramic particles for applications ...

Vascular composites enable dynamic structural materials

Jul 26, 2011

Taking their cue from biological circulatory systems, University of Illinois researchers have developed vascularized structural composites, creating materials that are lightweight and strong with potential for self-healing, ...

New family of composite structures

Jan 13, 2012

Material scientists at ETH-Zürich are working on composite materials that mimic the structure of seashells. Such complex structures are produced using tiny magnetic particles which guide the composites' ...

Restraint improves dielectric performance, lifespan

Oct 25, 2011

Just as a corset improves the appearance of its wearer by keeping everything tightly together, rigidly constraining insulating materials in electrical components can increase their energy density and decrease their rates ...

Recommended for you

Lifting the brakes on fuel efficiency

Apr 18, 2014

The work of a research leader at Michigan Technological University is attracting attention from Michigan's Governor as well as automotive companies around the world. Xiaodi "Scott" Huang of Michigan Tech's ...

Large streams of data warn cars, banks and oil drillers

Apr 16, 2014

Better warning systems that alert motorists to a collision, make banks aware of the risk of losses on bad customers, and tell oil companies about potential problems with new drilling. This is the aim of AMIDST, the EU project ...

User comments : 0

More news stories

Hackers of Oman news agency target Bouteflika

Hackers on Sunday targeted the website of Oman's official news agency, singling out and mocking Algeria's newly re-elected president Abdelaziz Bouteflika as a handicapped "dictator".

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Easter morning delivery for space station

Space station astronauts got a special Easter treat: a cargo ship full of supplies. The shipment arrived Sunday morning via the SpaceX company's Dragon cargo capsule.