Composites and hybrid materials will define the future of manufacturing – and with good reason: These strong yet lightweight materials that comprise half of all commercial twin-aisle airplanes and most electrical vehicles are lighter and more fuel efficient, lessening their carbon footprint.  

However, because composites are unique (combining different materials), it is difficult to model how they will degrade and fail during use. Also, impact damage may not be visible or may be barely visible, making it harder to detect than damage to metallic structures. Furthermore, repairing these materials and structures is both time-consuming and expensive due to the complexity of composite parts and lack of experience or knowledge and data.

Based at the Georgia Institute of Technology, the Center for Composite and Hybrid Materials Interfacing (CHMI) intends to dramatically improve how composite and hybrid structures are joined and repaired. The Center is one of four active NSF Industry/University Cooperative Research Centers (IUCRCs) at Georgia Tech.

Funded for five years with an NSF IUCRC grant, the Center will work closely with an industry consortium of leading manufacturers and government organizations that will underwrite research projects.

Housed in the Georgia Tech Manufacturing Institute (GTMI), the Center incorporates three university research teams from Georgia Tech, Oakland University, and University of Tennessee, Knoxville (UT). Each research and development partner brings decades of composite and hybrid materials research focus in specific industries: Georgia Tech in aerospace, Detroit-based Oakland University in automotive composite systems, and UT in infrastructure and medical devices.

“The study of the interface between composite, metallic and other electronic materials is really the future of manufacturing,” said Ben Wang, executive director of GTMI. “The Center amplifies the thought leadership of Georgia Tech advancement in composites. It also puts us in the nexus of three areas -- advanced manufacturing, innovative materials and data analytics.”

Improving Composite Repair Efficiency with Analytics and Automation

Center director Chuck Zhang, Harold E. Smalley Professor in Georgia Tech’s H. Milton Stewart School of Industrial and Systems Engineering (ISyE), will drive CHMI’s vision to transform the current labor-intensive, experience-based joining and repair practice into fast, automated and reliable processes.

“Using advanced computation, experimental data analytics, and digital techniques and tools, we hope to reduce by 50% the overall cost, cycle time and variation of these processes in the next 10 years,” Zhang said.

As an IUCRC, the Center will engage Georgia Tech and partner faculty and researchers and students, in addition to industry partners. Each university partner will rotate hosting in-person briefings with the consortium every six months, with the first meeting set for October at GTMI.

The frequent engagement between researchers and industry partners will “help ensure a strong understanding of the challenges and possible solutions. The outcome is really a very robust research agenda,” said Wang.

The Center will solve key challenges facing industries that rely on composite materials. To illustrate, a bird striking a plane can damage a composite structure on the wing of the aircraft. The airline company or maintenance provider must then deploy specialized, expensive patches – often to remote locations. There are training challenges with technicians, as well as the high cost of grounding a plane. Pulling an Airbus A350 out of service for a single day costs an airline an estimated $100,000 or more in lost revenue.

Repairing composites represents a supply chain challenge beyond one company’s capabilities to solve. 

“No company can do this on their own – it's too multidisciplinary,” said Rob Maskell, chief scientist of global composite manufacturer Solvay Materials. “Solving this challenge is critical to the increased adoption of composites, and I think Georgia Tech brings a lot of competencies that, when combined with Solvay’s expertise, gives us credibility.”

Solvay Materials: Finding Solutions to a Multi-Disciplinary Challenge

Solvay Materials has been involved from the beginning and is one of the Center’s eight founding consortium members. The Belgium-headquartered company is the leading supplier of structural adhesives for composite bonding on aircraft. It is estimated that 55% of all twin-aisle commercial jets contain composites.

“Joining industry and academia in this Center is an essential piece on the road to the increased commercialization and adoption of composites,” Maskell said.

Maskell noted that the current manual repair process for composites could be replaced with analytics, automation, and digital technologies. He also sees additive manufacturing – or 3D printing of composite parts – as a future key efficiency driver.

Building Future Workforce while Enhancing Skills of Current Engineers

The Center also will help support workforce development in the composite area, both to educate graduate and undergraduate students and create a funnel for future workers in the industry once they graduate. Wang said the Center will also create a technology and knowledge database of new tools for companies to use in their production lines. Georgia Tech leadership sees it as a win-win for researchers and industry.

“Getting this Center approved will benefit quite a few faculty members. We have expertise in trends and applications in artificial intelligence and machine learning,” said Edwin Romeijn, ISyE H. Milton and Carolyn J. Stewart School Chair and professor. “The Center also touches on issues of supply chain design and management, and transportation and autonomous vehicles, which are very big strengths of ISyE as well.”

Joining Zhang from Georgia Tech are co-principal investigators Christopher Muhlstein and Donggang Yao, both professors in the School of Materials Science and Engineering. Yao focuses on creating materials and developing material systems to make and join composites together, while Muhlstein studies the mechanical behavior of these materials. Zhang’s background in multifunctional composites, additive manufacturing, and applications of data analytics ties it all together.

“As an engineer of composites, you need all these pieces,” explained Muhlstein, who strives to create a more predictable, reliable, and high-confidence bond between the composites and the structures. “The moment that you can use the composite all the way to its limit, and do that with confidence, now you enable whole new classes of airplanes and cars ― or even completely new applications.”

Guided by Technology Roadmap, Industry Engagement

The CHMI launches with a well-defined technology roadmap, having benefited from earlier grant and collaborative discussions with industry partners.

According to Zhang, the concept for the Center originated in 2015, when Georgia Tech received a National Institute of Standards and Technology grant to identify top challenges and R&D needs facing aerospace companies and then develop a 10-to-15-year technology roadmap focused on research in that area. More than 50 companies and government organizations, including Boeing, Lockheed Martin, Airbus, and component manufacturing suppliers were polled on their top five technology challenges, and “composite joining and repair was one of the top three technology areas cited,” Zhang recalled.

The Georgia Tech principal investigators consider the deep materials and analytics expertise at Georgia Tech a key strength of the Center. Having industry involvement ensures that “we as researchers get great problems to work on,” said Muhlstein. “This Center allows us to create a convergent platform where industry comes together with academia in both a structured and targeted way to advance manufacturing in the U.S.”

The CHMI’s founding industry coalition members are Air Force Life Cycle Management Center, Boeing, Corvid Technologies, Hexcel, RUAG Space USA, Spirit AeroSystems, Solvay, and Top Flight Aerostructures.

*Editor's note: All photos and video for this story were taken in July 2021, prior to updated mask guidance issued by Georgia Tech.