PETEKKAYA, Ali Tolga Orta Doğu Teknik Üniversitesi - Makina Mühendisliği Bölümü, Turkey , TÖNÜK, Ergin Orta Doğu Teknik Üniversitesi - Biyomalzeme ve Doku Mühendisliği Mükemmeliyet Merkezi - Makina Mühendisliği Bölümü, Biyomedikal Mühendisliği Disiplinlerarası Lisansüstü Programı, Turkey

IN VIVO INDENTER EXPERIMENTS VIA ELLIPSOID INDENTER TIPS TO DETERMINE THE PERSONAL AND LOCAL IN-PLANE ANISOTROPIC MECHANICAL BEHAVIOR OF SOFT BIOLOGICAL TISSUES

16490

Mechanical interaction of human body with surrounding is mostly via soft tissues because human body is nearly entirely covered with them. Finite element method, extensively used in various fields of engineering, could not reach to a similar success in simulating soft tissues (especially for modeling the interaction with exoskeletal prosteses and orthoses) mainly because soft tissue mechanical behavior is not known in detail in addition to relatively complex mechanical response of soft tissues. In vivo cyclic, relaxation, and, creep indenter experiments with axially asymmetric ellipsoid tips were performed on forearm soft tissues to obtain a constitutive equation and related material coefficients to model soft biological tissues in large strain, considering material nonlinearity, mechanical energy dissipation and anisotropy.The results obtained are similar to those in literature, however, preconditioning (Mullin) effect was observed in hysteresis. It was sufficient to use a two-term Prony series to model the inelastic behavior. To model the preconditioning (Mullin) effects it may be necessary to add a third term to Prony series, however, experiments for this purpose were not conducted. The parameters modeling the inelastic behavior were direction dependent

63

Soft biological tissue , material characterization , indenter experiments , nonlinear viscoelastic properties , anisotropy

Journal Of The Faculty Of Engineering an‎d Architecture Of Gazi University

72