A recent award from the U.S. Defense Advanced Research Projects Agency (DARPA) brings together researchers from Massachusetts Institute of Technology (MIT), Carnegie Mellon University (CMU), and Lehigh University (Lehigh) under the Multiobjective Engineering and Testing of Alloy Structures (METALS) program. The team will research novel design tools for the simultaneous optimization of shape and compositional gradients in multi-material structures that complement latest high-throughput materials testing techniques, with particular attention paid to the bladed disk (blisk) geometry commonly present in turbomachinery (including jet and rocket engines) as an exemplary challenge problem.
“This project could have necessary implications across a wide selection of aerospace technologies. Insights from this work may enable more reliable, reusable, rocket engines that may power the subsequent generation of heavy-lift launch vehicles,” says Zachary Cordero, the Esther and Harold E. Edgerton Associate Professor within the MIT Department of Aeronautics and Astronautics (AeroAstro) and the project’s lead principal investigator. “This project merges classical mechanics analyses with cutting-edge generative AI design technologies to unlock the plastic reserve of compositionally graded alloys allowing secure operation in previously inaccessible conditions.”
Different locations in blisks require different thermomechanical properties and performance, similar to resistance to creep, low cycle fatigue, high strength, etc. Large scale production also necessitates consideration of cost and sustainability metrics similar to sourcing and recycling of alloys within the design.
“Currently, with standard manufacturing and design procedures, one must give you a single magical material, composition, and processing parameters to satisfy ‘one part-one material’ constraints,” says Cordero. “Desired properties are also often mutually exclusive prompting inefficient design tradeoffs and compromises.”
Although a one-material approach could also be optimal for a singular location in a component, it could leave other locations exposed to failure or may require a critical material to be carried throughout a complete part when it could only be needed in a particular location. With the rapid advancement of additive manufacturing processes which are enabling voxel-based composition and property control, the team sees unique opportunities for leap-ahead performance in structural components are actually possible.
Cordero’s collaborators include Zoltan Spakovszky, the T. Wilson (1953) Professor in Aeronautics in AeroAstro; A. John Hart, the Class of 1922 Professor and head of the Department of Mechanical Engineering; Faez Ahmed, ABS Profession Development Assistant Professor of mechanical engineering at MIT; S. Mohadeseh Taheri-Mousavi, assistant professor of materials science and engineering at CMU; and Natasha Vermaak, associate professor of mechanical engineering and mechanics at Lehigh.
The team’s expertise spans hybrid integrated computational material engineering and machine-learning-based material and process design, precision instrumentation, metrology, topology optimization, deep generative modeling, additive manufacturing, materials characterization, thermostructural evaluation, and turbomachinery.
“It is particularly rewarding to work with the graduate students and postdoctoral researchers collaborating on the METALS project, spanning from developing latest computational approaches to constructing test rigs operating under extreme conditions,” says Hart. “It’s a really unique opportunity to construct breakthrough capabilities that might underlie propulsion systems of the long run, leveraging digital design and manufacturing technologies.”
