The Role of Cavity and Interface Interactions in Damage and Injury of Biological Materials for Protective Measures
Abstract
Approved for Public Release PROBLEM OVERVIEW AND IMPACT ON DOD CAPABILITIES: The acute need for accurate and reliable prediction ofthe resilience of the human body in presence of extreme loading conditions is addressed in the proposed work. Its results will therefore have immediate implications on the design criteria for ship and aircraft maneuvering and Personal Protective Equipment (PPE), which directly influence the safety of individual service members. While cavitation is thought to be a primary mechanism of damage in the brain and in other soft tissue that are subjected to extreme loads and blast, the focus in the literature has been on the investigation of isolated cavities. However, it is anticipated that several cavities can form simultaneously, and nearby cavities can interact and may even merge. Though such processes are commonly reported in fluids, they are rarely studied in solids and are thus notwell understood. In contrast to fluids, interactions between initially isolated events in a solid can lead to propagation of damageand to acute injury of the tissue. Understanding such phenomena requires the development of advanced experimental and theoretical techniques that can elucidate the damage mechanisms and relies on accurate measures of mechanical properties of biological tissue. However, reported properties in the literature vary in orders of magnitude. This irreproducibility has not only hindered the ability to obtain significant insights into the basic mechanisms of damage, but also prevents the maturation of large-scale computational platforms which are developed to simulate extreme response of the human body.PROJECT OBJECTIVES: To combat this challenge the proposed work plan will address significant gaps in the current knowledge, to meet two primary objectives:1. Elucidate the basic mechanisms of damage in soft and biological materials by accounting for the complexities associated with heterogeneity that can drive propagation of damagethrough cavity-cavity and cavity-interface interactions.2. Advance mechanical testing methods to accelerate and streamline data acquisition and mechanical characterization of soft biological tissue.TECHNICAL APPROACHES: The three Thrusts of this work will simultaneously drive the proposed research to achieve the objectives of this work. Thrust I will investigate the interactions between nearby cavities and the role of those interactions on the propagation of damage and emergence of mechanical instabilities that can ultimately lead to merger of cavities. Thrust II will focus on the interaction between cavities and material interfaces. To study realistic scenarios of tissue injury, interfacial cavitation and its transition to interfacial delamination willbe considered both at the interface between dissimilar materials and in finite samples. Dedicated experimental setups will be developed for Tasks I and II and will leverage the Volume Controlled Cavity Expansion (VCCE) method,developed by PI Cohen#s team. These experiments will be complemented by theoretical models that will further elucidate the mechanical phenomena in both synthetic and biological materials. Thrust III of the proposed research will complement the efforts in Tasks I and II by enhancing and accelerating mechanical characterization of soft biological tissue. A current bottleneck will be resolved by translating the VCCE setup to a portable device. Testing protocols and data analysis methods will be enhanced and streamlined thus establishing a platform that can be extended to a myriad of biological systems and organs.ANTICIPATED OUTCOMES: The proposed work will advance basic knowledge on the extreme behavior of biological materials and will accelerate characterization of soft tissue mechanical properties, thus enabling the development of mechanical database of material properties of the human body and enhanced safety measures for the resilience of biological tissue.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 29, 2023
- Source ID
- N000142312530
Entities
People
- Tal Cohen
Organizations
- Massachusetts Institute of Technology
- Office of Naval Research
- United States Navy