Unraveling materials’ microstructure

ASU Regents Professor Aditi Chattopadhyay pioneers materials engineering while mentoring students

Advances in materials science — such as the discovery of materials that can withstand harsh environments and the engineering of adaptive, self-repairing structures — have led to increased safety and durability in the systems we rely on daily.

Regents Professor Aditi Chattopadhyay is one of many Arizona State University researchers, engineers and scientists working to advance the human condition. A mechanical and aerospace engineering faculty member in the School for Engineering of Matter, Transport and Energy, part of the Ira A. Fulton Schools of Engineering at ASU, Chattopadhyay is among the world’s top researchers in the fields of adaptive structures, advanced materials research, structural health monitoring and related areas. Through her work, she is exploring how to expand our understanding of materials’ behavior in extreme environments and ensure complex structures are safe, adaptable and highly durable.

She recently took some time to discuss her work’s impact and her collaborations with students.

What inspired you to pursue your research?

In science and engineering, we learn how to solve problems using existing theories and models. I’m curious about the governing principles and the hypotheses these theories were built on. How good are they, and can we improve them?

As an aerospace engineer, I learn something new every day and study topics that are outside my comfort zone. Advancing the science of complex materials structures and other areas I’m interested in is my primary source of inspiration.

You’ve worked with the U.S. military, NASA and the U.S. Department of Energy. What would you say has been the real-world impact of your work? How did it benefit society?

My group strives to ensure that our research addresses current knowledge gaps and complements existing research findings. Active collaboration with industry partners has helped transition some of our research outputs to their in-house use. I maintain close collaboration with researchers from government labs to identify critical challenges and their needs.

Your most cited research paper on Google Scholar is “Dynamic instability of composite laminates using a higher order theory.”  What study was the paper about? What were you trying to understand, and what were the results?

Composites are made by combining two or more materials to achieve enhanced properties like strength and stiffness, and are increasingly used in aerospace applications. However, their behavior under static and dynamic compressive loads has largely been investigated using simple models that either ignore or make rough adjustments to account for transverse shear stresses that develop through the thickness of the material.

As a result, these models underestimate deflections, the amount a structure deforms under load, overestimate buckling loads, the critical force at which a structure becomes unstable, and overestimate natural frequencies, the inherent rates at which a structure tends to vibrate. Understanding these behaviors accurately is critical to assessing the performance of composites in a dynamic loading environment.

My group introduced a new and more accurate mathematical model, or variationally consistent higher order theory, that better captures how the transverse stresses affect the response of composite materials. This model helps predict how composites with various geometry behave under changing loads, including how damage between layers impacts their stability and vibration patterns. This generalized theory is applicable to a wide range of composites and has been used by several researchers.

How do you see your research advancing in the future?

My goal is to develop highly accurate modeling techniques that account for multiple physical processes at different material length scales, addressing damage and oxidative degradation in ultra-high temperature ceramic and polymer matrix composites used in hypersonic, space and engine applications.

Why did you choose to conduct your research at ASU? 

ASU provided me with the right environment and support.

Propelling students’ success

A big part of Chattopadhyay’s work at ASU is to teach and mentor students as they pursue their goals. Working with Mohamed Hamza, a Fulton Schools mechanical and aerospace engineering postdoctoral researcher who recently defended his mechanical engineering doctoral dissertation, she developed a multi deep learning framework to automatically map out the internal structure of materials.

The framework is designed to aid the accurate representation of complex composites’ microstructural characteristics, which are essential to developing highly precise modeling techniques for materials at various scales. 

Hamza says he expanded his knowledge significantly while working on this project.

What challenges did you encounter while developing the multi deep learning framework for automated microstructure reconstruction? 

Developing a deep learning framework that can account for the unpredictable variations in materials’ internal structure was challenging. Particularly, training a stable generative artificial intelligence model that could convert Gaussian noise, or random data following a bell-curve distribution pattern, into meaningful microscopic patterns.

How did Dr. Chattopadhyay support you throughout the project? 

Professor Chattopadhyay consistently provides challenging topics and tasks, which foster innovation and development of multidisciplinary skills among students. She actively encourages me to propose new research ideas and gives me critical feedback, which significantly enhances the quality and robustness of my research output.

She always allows me to participate in project review meetings and conferences, which enables me to develop public speaking skills and receive constructive feedback from experts in the field.

Her support has enabled my dissertation and publications to have a multifaceted impact on ongoing projects in the U.S. Department of Energy, the U.S. Department of Defense and NASA laboratories.

What did you learn while working on this project? 

I acquired a strong foundation in machine learning and various deep learning architectures, and I learned how to apply the technologies to analyze in detail the microscopic internal structure of ceramic matrix composites.

Forging future innovations

Hamza has recently transitioned to a postdoctoral researcher position in Chattopadhyay’s group.

Chattopadhyay says she is excited for advancements happening in the complex materials field and is looking forward to playing her part in accelerating the growth.“I’m excited to implement our high-fidelity computational models within the Integrated Computational Materials Engineering paradigm and contribute to the Materials Genome Initiative,” she says.