needle insertion is a minimally invasive technique in diagnosing and treating tumors. however, to perform a surgery accurately, the tissue should have minimum amount of displacement during needle insertion so that it reaches the target tissue. therefore, the tissue membrane has to move less to decrease rupturing under the membrane. in this study, the effect of different design parameters on dis...

Needle insertion is a minimally invasive technique in diagnosing and treating tumors. However, to perform a surgery accurately, the tissue should have minimum amount of displacement during needle insertion so that it reaches the target tissue. Therefore, the tissue membrane has to move less to decrease rupturing under the membrane. In this study, the effect of different design parameters on dis...

PURPOSE The aim of this study is to propose a method to construct corneal biomechanical model which is the foundation for simulation of corneal microsurgery. METHODS Corneal material has two significant characteristics: hyperelastic and viscoelastic. Firstly, Mooney-Rivlin hyperelastic model of cornea obtained based on stored-energy function can be simplified as a linear equation with two unk...

Intraoperative brain retraction leads to a misalignment between the intraoperative positions of the brain structures and their previous positions, as determined from preoperative images. In vitro swine brain sample uniaxial tests showed that the mechanical response of brain tissue to compression and extension could be described by the hyper-viscoelasticity theory. The brain retraction caused by...

The complex structural and material behaviour of the human heel fat pad determines the transmission of plantar loading to the lower limb across a wide range of loading scenarios; from locomotion to injurious incidents. The aim of this study was to quantify the hyper-viscoelastic material properties of the human heel fat pad across strains and strain rates. An inverse finite element (FE) optimis...

Cerebrospinal fluid (CSF) pulsations have been proposed as a possible causative mechanism for the ventricular enlargement that characterizes the neurological condition known as hydrocephalus. This paper summarizes recent work by the authors to anaylze the effect of CSF pulsations on brain tissue to determine if they are mechanically capable of enlarging the cerebral ventricles. First a poroelas...

The objective of this study is to develop robust finite element models of the liver and kidney. The organs are modeled for the first time as hyper viscoelastic materials and with individual constituents of each (viz. the capsule and veins). To characterize the tissues, static and dynamic experiments were performed on individual parts of the porcine abdominal o...

the effect of temperature on the viscoelastic behavior of chicken meat frankfurters was assessed by creep recovery tests. compression creep-recovery tests were performed at room temperature (20°c) and refrigeration (5°c) on samples of cylindrical shape. the viscoelastic behavior of samples was characterized based on the parameters of the four-element burgers model. during the compression phase,...

This paper contains experimental results of in vitro, uniaxial tension of swine brain tissue in finite deformation as well as proposes a new hyper-viscoelastic constitutive model for the brain tissue. The experimental results obtained for two loading velocities, corresponding to strain rates of 0.64 and 0.64 x 10(-2)s(-1), are presented. We believe that these are the first ever experiments of t...