SRMP Seminar: July 24

[AEM Communications]

Good morning,

We invite you to attend the upcoming SRMP seminar this Friday.

Friday, July 24, 2026

225 Akerman Hall

2:30pm-3:30pm

First Talk:

Title: Investigation of Nonequilibrium Methods using a Stagnation Line Solver

Abstract: For high-speed re-entry conditions, the flow-field surrounding the vehicle of interest can be in thermochemical nonequilibrium. In these cases, phenomena such as dissociation, ionization, and energy exchange between internal energy modes become important. In order to simulate these conditions, a number of additional equations need to be solved in a computational fluid dynamics (CFD) code. Many modelling choices exist to simulate these conditions, and as such, running through every permutation of these choices is computationally exhausting for two- and three-dimensional flow fields. By using a reduced form of the nonequilibrium Navier-Stokes equations, many one-dimensional cases can be run fairly accurately in a fraction of the time. The  results of these cases will assist to better understand the assumptions of each modelling choice and how they affect certain flow features. On top of this, reduced order models for quantities such as shock stand-off distance, heat transfer, and the degree of nonequilibrium can be developed from a large database of results.

Speaker Bio:  Connor Switala is a second year graduate student in the Computational Hypersonics Research Group, where he is advised by Professor Graham Candler. His work focuses on investigating nonequilibrium models for high-speed flows. He works closely with Anthony Knutson to assist in new C++ code for nonequilibrium flow computation.

Second Talk:

Title: Unraveling Tension–Compression Failure Asymmetry in Soft Solids via Logarithmic-Strain Invariants

Abstract: Soft materials often exhibit pronounced tension–compression asymmetry (TCA) in their softening and failure behavior, a feature that conventional hyperelastic and continuum-damage formulations fail to capture within a unified framework. This work presents a Lode-invariant-based hyperelastic softening model that explicitly incorporates deformation-mode dependence through a bi-failure construction with distinct tensile and compressive energy limiters. The proposed model extends Volokh’s classical energy-limiting approach by embedding a Lode-angle-dependent weighting function within failure and elastic energy descriptions, which ensures a smooth and thermodynamically consistent transition of failure behavior across distortion modes, achieved directly within the constitutive description of the bulk response—without introducing internal damage variables. Agarose hydrogels (1, 2, and 3% w/v) serve as the model system for validation. The framework accurately reproduces experimental stress–stretch responses in uniaxial tension and compression, capturing concentration-dependent stiffness and failure energetics. Using parameters calibrated solely from combined uniaxial data, the model successfully predicts pure shear behavior—including softening and failure—demonstrating strong cross-mode generalizability. To further assess thermodynamic stability and deformation-mode sensitivity, the proposed model’s strain energy density landscape was analyzed across the full Lode invariant space, confirming its consistent and stable behavior under diverse loading conditions. Parameter evolution with concentration follows power-law scaling, enabling interpolation and predictive validation at intermediate concentrations (evaluated at 2.5% w/v). By establishing a physically interpretable failure modeling framework over the Lode invariant space, this work provides a unified framework for tension–compression–asymmetric softening and lays the foundation for distortional-mode-sensitive, three-dimensional failure mapping of soft materials.

Speaker Bio: Yogesh Chandrashekar is a fourth-year Ph.D. student in the Soft Materials Mechanics Lab under the guidance of Prof. Kshitiz Upadhyay. His research focuses on understanding the mechanics of damage and failure in soft materials, such as hydrogels and elastomers, by integrating advanced experimental techniques with theoretical modeling. Outside of research, he enjoys swimming and playing table tennis.

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