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Sun Research Group
Multiscale Materials Modeling and Computation
Research overview
Our research focuses on the fundamental challenges of understanding and predicting the mechanical properties of materials across a wide range of time and length scales in three extreme environments:
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High strain rates: How do metals and alloys respond to high-velocity impact and other dynamic loading? How do their microstructures and microscopic properties govern this performance?
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Hydrogen-rich atmospheres: How does hydrogen interact with lattice defects in metals? How do these interactions lead to hydrogen embrittlement and changes in mechanical behavior?
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Structural collapse: How do architected metamaterials behave under extreme loading? How do manufacturing imperfections affect their stability, strength, and stiffness?
These conditions and issues are critical to applications in aerospace, defense, and nuclear engineering. The following sections highlight the research projects currently led by our group.
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Characterizing the Dynamic Performance of Advanced Alloys under High-Velocity Impact
Our group integrates advanced computational modeling, data-driven methods, and experiments to understand and predict material behavior under high-velocity impact (HVI) conditions. We develop a machine-learning-based framework for optimal uncertainty quantification to establish rigorous probabilistic bounds on failure and guide uncertainty-aware material design. We also quantify how uncertainties in plasticity and fracture models influence impact performance and create an ensemble-based data assimilation framework that enables automatic calibration of material parameters using data from a single HVI test. Complementing these computational advances, we experimentally investigate short-range ordering in medium-entropy alloys to reveal its role in governing impact response.
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Unraveling the Interactions between Hydrogen and Lattice Defects in Metals Across Multiple Time Scales
Our group develops multiscale modeling frameworks to elucidate hydrogen-defect interactions and hydrogen-induced phase transformations in metallic systems. By integrating atomistic techniques such as Diffusive Molecular Dynamics and Molecular Dynamics, we investigate solute-defect interactions in nanoscale metal-hydrogen systems across multiple time scales. These studies uncover the fundamental mechanisms governing hydrogen-driven phase transformations and sorption hysteresis in metallic nanoparticles and reveal how particle size and shape influence hydrogen absorption and release behavior.
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Quantifying Imperfections in Architected Mechanical Metamaterials under Extreme Collapse Loading
Our group investigates the mechanics and design of architected materials through a combination of experiments, simulations, and uncertainty analysis. We fabricate architected materials using additive manufacturing and conduct compression tests to evaluate their mechanical performance. To complement these experiments, we develop a computational framework based on limit analysis and finite element methods to rapidly predict the stiffness, yield strength, and ultimate strength of these architected materials. Additionally, we quantify how manufacturing imperfections, such as variations in strut geometry and buckling behavior, affect the mechanical response and reliability of these materials under extreme loading conditions.
We gratefully acknowledge the support of the following agencies for their funding on our research projects:
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