טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentSoussan Maor
SubjectSoft Biological Tissues Cavitation and Penetration
Mechanics
DepartmentDepartment of Aerospace Engineering
Supervisors Professor Emeritus David Durban
Dr. Rami Masri


Abstract

Recent progress in experimental biomechanics has provided reliable hyperelastic constitutive parameters for a variety of soft biological tissues like brain, kidney and liver. These laboratory-verified strain energy functions enable accurate analytical and numerical evaluation of complicated mechanical response of soft bio tissues, at large strains. Advances in diagnosis, numerical simulation and design of medical procedures have followed accordingly. In particular, research of soft tissues ballistic impact phenomena (perforation and penetration) can now be investigated within the framework of nonlinear continuum mechanics. This development stands in marked contrast to earlier studies, performed over decades, where substitute materials like ballistic soap or ballistic gelatin were used to assess the resistance of bio tissues to ballistic impact.   

The aim of the present work is to suggest a new model for the mechanics of deep penetration of rigid projectiles into soft tissues. The study centers on the dynamic cavitation model which has been successfully employed in solid targets penetration analysis. The underlying assumptions are rigid point headed projectiles, normal impact at small firearms velocity range and straight penetration path. Material behaviour is hyperelastic, isotropic and incompressible, with simple post failure behaviour. Inertia effects are accounted for and both spherical and cylindrical cavitation patterns are considered. The study starts with literature review and background chapters in order to provide the present state of relevant research and understanding of basic agreed upon ideas, and paves the way for presenting and discussing this work findings.