Nadia Aljabi is not your typical undergraduate civil engineering student.

The daughter of a Syrian father and Costa Rican mother, Aljabi has already traveled much of the world, seeing firsthand how many countries lack the basic infrastructure to live comfortably and productively. Her response: Work to mitigate the impact of natural disasters that cost lives and untold property damage.

“As a civil engineering student at Purdue, I am learning the necessary skills and technical knowledge to be an active contributor to society in a way that’s beneficial and long-lasting,” says Aljabi, who hopes to pursue a doctoral degree in engineering or education.

To that end, Aljabi worked with associate professor Pablo Zavattieri and David Restrepo Arango, a graduate research assistant and doctoral student, exploring the development of special materials — called phase-transforming cellular materials (PXCMs) — that can absorb energy and help mitigate damage in the structural components of buildings, bridges and other large structures. The plastic-like materials also are reusable and are less expensive than existing energy absorption/damage mitigating materials.

Zavattieri is collaborating with General Motors Corp. to develop a new type of energy-absorbing material that might be 3D printed and that could have an impact in areas ranging from earthquake engineering to safer football helmets.

The research experience changed her understanding of the ways civil engineers can make a difference. “Now I realize this contribution can either be done as a direct field engineer or as an active participant in the advancement of science and technology through research,” says Aljabi, who is studying in Colombia this spring.

Her summer 2015 project, part of Purdue Engineering’s Summer Undergraduate Research Fellowship (SURF) Program, focused on the fabrication method for PXCMs based on different approaches using 3D printing. CAD models were first designed following analytical tools. Those models then were 3D printed and assembled together so researchers could explore the fabrication of PXCMs in different materials without relying on 3D printing.

Aljabi then examined the geometric design space of the PXCMs that exhibits phase transformation in two or more preferential directions. For this, the team developed 2D and 3D geometric designs, performing a parametric study by using 3D-printed models to explore the behavior of each cell.

The results: They observed that most of the 3D geometric models revealed the expected PXCM behavior under the same conditions — bi-stability and meta-stability, energy absorption and phase transformation capabilities. These experimental results are important for the development of new theories and computational models that will be employed for the design of PXCMs for specific applications.

“We determined these unit cells can be linked together to form a product that can be included in structural members to improve structural resistance,” she says. “Further testing, however, is needed to determine the ratio that would allow the 1D and 2D models to demonstrate snap-through behavior, meaning the structures can flex back and forth and remain in either position indefinitely, not unlike a flexing playing card.”

Adds Zavattieri: “Nadia is very professional, a brilliant student, and a straightforward and open-minded person. She critically thought and questioned the material for the PXCM project. It’s rewarding to work with a student who is such a dedicated team member, and who has the talent to advance this research.”