Inertial Microcavitation Rheometry of Anisotropic Biological Tissues
Abstract
Digital engineering harnesses predictive computational modeling for iterative engineering designthat minimizes the need for expensive testing, and this approach has been deployed in thedesign of complex engineering systems. However, this process neglects loads and deformationsapplied to human occupants, which is a crucial aspect of predicting potential injuries and henceoccupant safety. A keyimpediment to predictive digital engineering involving the mechanicalinteractions between humans and engineered systems is the highstrain-rate constitutive behaviorof biological tissues, which is required as an input but remains a source of uncertainty. Therefore,there is a need for improved constitutive modeling of biological tissues over a broad range of strainrates. Calibrated, predictiveconstitutive models for soft biological tissue materials are currentlylacking because applying traditional high strain-rate material characterization techniques to softmaterials is challenging. To address this need, a soft-material characterization technique, calledInertial Microcavitation Rheometry (IMR), has been developed using measurements of the dynamicsof isolated bubbles generated by laser or acoustic pulses. Using high-speed imaging of thebubble dynamics along with a cavitation modeling framework provides a route to high strain-ratesoft material characterization, and IMR has been shown to be able to discern mechanical propertiesat previously undocumented strain rates in materials as soft as a few kilopascals. In the proposedproject, IMR will be leveraged to obtain calibrated high strain-rate constitutive models for severaltypes of anisotropic biological tissue, including kidney, liver, and muscle tissue. To date, IMRhas only been applied to obtaining material properties for isotropic models. The proposed worktackles the challenge of extending IMR to anisotropic materials. The first aim of the proposedproject is to establish a robust methodology for applying IMRin an anisotropic material, usingcleared muscle tissue as a benchmark optically-clear soft material, so that it may be verified thatthe anisotropic IMR process (a-IMR) yields consistent parameters for both isolated bubbles andbubbles in thin slices. Then, the second aim moves to applying a-IMR to uncleared tissues ofinterest to the Naval Forces, specifically, kidney and liver. Finally, Aim 3 moves to applying a-IMRto skeletal muscle tissue, which is anticipated to be the most anisotropic biological material of interest.The proposed scope of work is fundamental research, having civil and military applications.Successful completion of the proposed work would result in a validated, extended version of IMRthat is applicable to anisotropic materials and provide a set of robust, large-strain, high strain-ratematerial properties for biological tissues. This material property data will enable predictive digitalengineering, potentially leading to improved strategies for mitigating and preventing injuries bothin the armed forces and amongst civilians (e.g., in sports-related injuries).
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 10, 2025
- Source ID
- N000142512254
Entities
People
- David L. Henann
Organizations
- Brown University
- Office of Naval Research
- United States Navy