Heart failure is a leading cause of death in New Zealand. In order to determine the causesof rhythm disturbances leading to failure a knowledge of the structure and mechanical behaviour of cardiac tissue is important. This paper presents realistic stress and strain distributions for the passive heart that have been reproduced using a three-dimensional finite element model of the ventricles base...

Sun, Jianzhuo. M.S.A.A., Purdue University, May 2014. Biaxial Shear/Tension Failure Criteria of Spectra single fibers. Major Professor: Weinong Chen. An experimental study was conducted to develop the biaxial failure surface criteria of single Spectra 130d and 100d filaments in a torsion-tension environment. The crosssectional profiles of single Spectra fibers were investigated using scanning e...

Mounting evidence suggests that the normal biomechanical state of arteries may include a nearly equibiaxial intramural stress and that arteries tend to undergo rapid and dramatic remodeling when perturbed from this normal state. Technical developments since the early 1980s have enabled in vitro (acute) and ex vivo (chronic culture) study of isolated, perfused microvessels, and it is clear that ...

A new acellular, natural, biodegradable matrix has been discovered in the cholecyst-derived extracellular matrix (CEM). This matrix is rich in collagen and contains several other macromolecules useful in tissue remodeling. In this study, the principal material axes, collagen fiber orientations, and biaxial mechanical properties in a physiological loading regime were characterized. Fiber directi...

A technique is presented for the constructions of stressstrain relations based on experimental, cyclic, damping data. The extension of this technique to the biaxial stress case is then shown followed by an example application involving flexural vibrations of a cantilever.

This article presents design, fabrication and characterization of lead zirconate titanate (PZT)-actuated micromirrors, which enable extremely large scan angle of up to 106◦ and high frequency of 45 kHz simultaneously. Besides the high driving torque delivered by PZT actuators, mechanical leverage amplification has been applied for the micromirrors in this work to reach large displacements consu...

By thermally cycling through their transformation temperature range, coarse-grained polymorphic materials can be deformed superplastically, owing to the emergence of transformation mismatch plasticity (or transformation superplasticity) as a deformation mechanism. This mechanism is presently investigated under biaxial stress conditions during thermal cycling of unalloyed titanium, Ti-6Al-4V, an...

Myocardial infarction was experimentally induced in rat hearts and harvested immediately, 7, 14 and 28 days after the infarction induction. Anterior wall infarct samples underwent biaxial tensile and uniaxial compressive testing. Orientation of collagen fibres was analysed following mechanical testing. In this paper, we present the tensile and compressive stress-strain raw data, the calculated ...

Tagged MRI and finite-element (FE) analysis are valuable tools in analyzing cardiac mechanics. To determine systolic material parameters in three-dimensional stress-strain relationships, we used tagged MRI to validate FE models of left ventricular (LV) aneurysm. Five sheep underwent anteroapical myocardial infarction (25% of LV mass) and 22 wk later underwent tagged MRI. Asymmetric FE models of...

We report elastic constant calculation and a "theoretical" tensile experiment on stoichiometric hydroxyapatite (HAP) crystal using an ab initio technique. These results compare favorably with a variety of measured data. Theoretical tensile experiments are performed on the orthorhombic cell of HAP for both uniaxial and biaxial loading. The results show considerable anisotropy in the stress-strai...