CEE Seminar (ZOOM): Bio-inspired Design and Additive Manufacturing of Cement-based Architected Materials

ZOOM link will be distributed by the CEE Department
Reza Moini, Ph.D.

Assistant Professor
Department of Civil and Environmental Engineering
Princeton University

Abstract:  New paradigms are needed to design and develop civil engineering materials and address the challenges of building sustainable urban infrastructure. This seminar presents a new approach for the purposeful design of cement-based materials inspired by architectures found in nature. The design of such cement-based “architected” materials are achieved through additive-manufacturing techniques, which have gained increasing interest among researchers and practitioners in the past few years. However, this nascent field is challenged by the lack of a fundamental understanding of the behavior of 3D-printed materials across scales, specifically the brittle or quasi-brittle behavior of cement-based materials and the weak interfaces induced during the layer-by-layer additive manufacturing. This seminar makes the case that additive manufacturing offers the opportunity to harness the role of heterogeneous interfaces in favor of materials’ mechanical properties. This can be done by incorporating clever design motifs as a means to trigger interfacial damage mechanisms in brittle cement-based systems that lead to achieving substantial toughness without sacrificing the strength. The use of direct ink writing, an extrusion-based additive-manufacturing technique, to fabricate structural elements in a layer-by-layer deposition process as well as X-ray micro-computed tomography to characterize the microstructural features of the hardened cement paste will be discussed. The evidence indicates that these new bio-inspired architected materials exhibit improved fracture resistance, de-localization of damage, enhanced energy dissipation and flaw-tolerant characteristics. This approach presents a viable route to control and diversify the mechanical responses of brittle materials that can lead to promising alternative avenues of design in the future.

Bio:  Reza Moini is an assistant professor in the Department of Civil and Environmental Engineering and an affiliate faculty member at the Andlinger Center for Energy and Environment at Princeton University. He received his bachelor's, master's and doctoral degrees in civil and environmental engineering from Qom University in Iran, the University of Wisconsin-Milwaukee and Purdue University, respectively. To supplement his academic endeavors, he has spent seven years in the industry as a structural engineer, most recently from 2013 to 2015 at Collins Engineers, Inc.

His research focuses on novel biomimetic designs enabled by automated robotic systems, the fundamental mechanics of architected materials and early-age deformations in cement-based materials with applications in civil and energy infrastructure. Moini is particularly motivated by the intellectual challenge of understanding the complex behaviors of 3D-printed materials, and his research seeks to translate the examined hypotheses into practical solutions in the construction sector. He has been the recipient of a number of research and teaching awards, and his publications have been featured in renowned peer-reviewed journals. Moini has codeveloped new courses and workshops in his area of expertise, and he has put forth ongoing industry collaborations supported by funding from the National Science Foundation.