CAREER: Tough Architected Concrete Materials: Bio-inspired Design, Manufacturing, and Mechanics

Princeton University, Princeton NJ

Investigators

Abstract

This Faculty Career Development (CAREER) award will support fundamental research on the design and fracture behavior of concrete with purposeful arrangements known as architected materials. Concrete is the most common human-made commodity used to build civil and energy infrastructure. However, without reinforcement, concrete suffers from low resistance to cracking and abrupt failure. To improve the shortcomings in mechanical response of cement-based materials, this project will focus on understanding and engineering stronger architected concrete for use in critical civil infrastructure and resilient structural applications. By applying concepts from naturally occurring strong materials such as mother-of-pearl (nacre) and bone that contain modest constituents, new types of concrete composites will be engineered with enhanced mechanical properties, superior to everyday unreinforced concrete counterparts. Through the design and analysis of novel construction materials using a laser process and advanced additive manufacturing, this project supports new applications of stronger and more damage-resilient infrastructure components that can enhance public safety and prosperity. The project will combine experimentation, computational modeling, and analytical approaches to create new methods for studying and designing these materials. Integration of research with educational and outreach activities, including (i) software development, (ii) additive manufacturing of concrete canoe for competition, (iii) development of a bio-inspired design course module, and (iv) participation in the bilingual Día de La Ciencia/Science Day program, will facilitate the use, adoption, and education among engineers, users, and students. The goal of this project is to understand and engineer the fracture behavior of architected concrete inspired by the brick-and-mortar arrangement of nacre and tubular arrangement of osteons in cortical bone. The research program will inform a new understanding of hypothesized toughening mechanisms from biological materials for the design, fabrication, and engineering of unreinforced concrete with enhanced ductility and fracture toughness benchmarked against ordinary and fiber-reinforced counterparts. To achieve these outcomes, the research integrates the following objectives: (i) study the underlying toughening mechanisms in natural materials and develop bio-inspired principles for design of synthetic counterparts and engineering the formulations of hard cementitious and soft hyperelastic constituents, (ii) create efficient manufacturing processes that enable fabrication of morphologically tailored hard-soft multi-material assemblies with purposeful internal defects, (iii) develop research and educational software and toolpath algorithms for additive processes that advance the design and fabrication, (iv) develop suitable experimentation for examining fracture toughness and strength of the architected materials and hard-soft constituents’ interfaces, and (v) develop a numerically robust constitutive framework for modeling fracture behavior in architected assemblies of soft and hard materials. The framework will utilize the phase-field approach to capture crack propagation within the bulk of the soft and hard materials, supplemented with a cohesive-zone model for the interfaces. The project will develop a foundation for understanding, engineering, and predicting the mechanical performance of tough architected composites and will generate new research avenues and design possibilities for crack-resilient applications. The project will allow the PI to advance the knowledge base in fracture mechanics and establish his long-term career in design and advanced manufacturing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.