Announcement Detail

Friday, July 31, 2026

1:00 PM CDT

Join via Zoom: https://us06web.zoom.us/j/82464478256?pwd=ZMkJVFdjMJzadgnVWFPqsdUSs4qTaY.1

Student Chapter Seminar Series

Physical mechanisms of blast-induced large deformations in brain-like soft matter

Speaker

Enze Chen, University of Wisconsin–Madison

Abstract

Blast-induced traumatic brain injury (bTBI) is a significant burden in the military population, often termed an invisible wound from training and combat. Although postmortem pathologies have been reported in the literature, the physical mechanism underlying their origin remains unclear. Several difficulties obstruct establishing direct causation between blast loading and injurious brain deformation: the fast shock transit and transient pressure loading, the inaccessibility of intracranial strain measurement, the complexity of brain anatomy and material behavior, and the limited availability of facilities generating well-controlled, open-field-like blast exposures at head scale.

In this presentation, I will present our recent work on measuring deformation in a skull–brain phantom from blast exposure and use numerical and theoretical analyses to elucidate the underlying physical mechanism. Biofidelic phantoms embedded with a speckle pattern are subjected to well-controlled blast exposures and imaged with a dual-camera system spanning two timescales, followed by digital image correlation for full-field deformation. This combined approach enables simultaneous observation of ultra-fast events driven by the primary wave and the later-stage material deformations via the much slower shear waves. Our measurement reveals that the shock transit stage produces no measurable deformation and cavitation, with injurious strain emerging only later through rotation-driven shear. Coupled numerical and theoretical analyses explain the physical chain from blast loading to the net moment and force on the phantom, which drives skull rotation and internal shear deformation. The resulting strain and strain rate are governed by the magnitude and frequency content of the net moment from blast loading relative to the phantom's torsional mode. This framework identifies the key parameters dictating brain strain and strain rate and offers key physical insight into postmortem pathology observed in humans from bTBI.

Bio

Dr. Enze Chen is a postdoctoral researcher in the Department of Mechanical Engineering at the University of Wisconsin–Madison. He received his Ph.D. in Civil Engineering from Johns Hopkins University in 2024. His research lies at the interface of solid mechanics and biology, where he develops experimental approaches to uncover the fundamental physical mechanisms governing injury of biological systems under extreme loading. By integrating nonlinear solid mechanics, high-rate experiments, and multiphysics modeling, he investigates how energy from various exposures such as blast waves and directed energy is transmitted through brain tissue and how the resulting deformations drive neurobiological responses at the cellular level. His research also spans mechanics of brittle and soft architected materials, advancing the understanding of brittle failure, nonlinear deformation, and mechanical instabilities in these material systems, while providing mechanics-based principles for the design of tissue-engineering scaffolds. His broader goal is to establish predictive, mechanics-based frameworks for biological systems that connect external loading to mechanical deformation and resulting biological response, enabling a mechanistic understanding of injury mechanisms and mechanobiology.