Research
The MATX Research Group seeks to explore the design, development, and characterization of materials and structures under extreme conditions for applications involving hypersonic vehicles, impact and blast of structures, armor/anti-armor, and aircraft and spacecraft/space structure shielding. Our overarching objectives are to advance our fundamental understanding of material behavior at high pressure, temperature, and strain rate loading conditions to design high strength, light weight, high temperature resistance materials.
Overview
Research
The MATX Research Group seeks to explore the design, development, and characterization of materials and structures under extreme conditions for applications involving hypersonic vehicles, impact and blast of structures, armor/anti-armor, and aircraft and spacecraft/space structure shielding. Our overarching objectives are to advance our fundamental understanding of material behavior at high pressure, temperature, and strain rate loading conditions to design high strength, light weight, high temperature resistance materials.
Overview
Spatio-temporal Mechanics of Materials
The development of materials with superior mechanical properties for extreme conditions (pressure > 10 GPa, and strain-rates > 1e5 s-1) requires extensive knowledge on the influence of microstructural changes on macroscopic response. Additionally, under these conditions, there is strong interplay between parameters such as pressure, temperature, strain, strain-rate, and damage that all affect the dynamic behavior of materials and must be decoupled. We leverage unique experimental facilities such as pressure shear plate impact techniques (PSPI), in addition to conventional servo-hydraulic machines, and split Hopkinson pressure bar to link the micro-structural to macroscopic response of materials. This is ensured by further coupling the experimental methods with various diagnostic techniques such as 3D and high-magnification DIC, DVC, PDV, and x-ray diffraction.
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Related Publications: S. Ravindran et al., J. Dyn. Behav. Mater. (2021), V. Gandhi*, S. Ravindran* et al., Rev. Sci. Instrum. (2023), V. Gandhi et al., Phys. Rev. Mater. (2023)
Additively Manufactured Architected Materials
Advancements in additive manufacturing have enabled fabrication of multi-functional architected lattices with tunable material properties (e.g., high stiffness-to-weight ratio), and exceptional mechanical behavior. Due to their ability to undergo large deformations at constant strains, these structural materials are critical in high energy absorbing applications such as helmets, armor, automobile, aircraft, and space structures. We are interested to explore the material design space (e.g., biomimetic, hierarchical, and active materials), energy absorption characteristics, and the role of strain-rate on the evolution of collapse mechanisms such as buckling, plastic deformation, and fracture. Our particular interest is to leverage the ability of architected structures to freely tailor and guide a propagating structural shock wave through novel topological designs.
Related Publications: J. Weeks et al. , Int. J. Impact Eng. (2022), A. Shaikeea*, D. Hahn* et al., J. Mech. Phys. Solids (2024)
Shock-Induced Phase Transformations
While, temperature-induced phase transformation has received significant attention, current understanding of the kinetics of shock-induced phase transformations and characterization of material properties is challenging and thus still limited. Using plate-impact techniques with in-situ x-ray diffraction at the Dynamic Compression Sector at the Advanced Photon Source, our group aims to explore the contribution of deviatoric stresses and impurities (e.g., adding carbon to iron) on the initiation and reverse-hysteresis of the phase transformation. Particularly, we are interested in the exploring the stability of mixed-phase regions and designing materials to leverage, for example, ductility of austenite but stiffness of martensite phases.
Related Publications: V. Gandhi et al,. Phys. Rev. Lett. (2022),