Ligaments, tendons and other soft tissues are nonlinearly viscoelastic. To discriminate among various constitutive equations which may be used to describe the tissue, appropriate experimental modalities are requisite. Ideally, testing should span physiologic ranges for load (or strain), load history (recovery and reloading), and load onset and duration, and a robust model will fit all data. Met...

The strain-dependent electrical resistance characteristics of multi-walled carbon nanotube (MWCNT)/polymer composite films were investigated. In this research, polyethylene oxide (PEO) is used as the polymer matrix. Two representative volume fractions of MWCNT/PEO composite films were selected: 0.56 vol% (near the percolation threshold) and 1.44 vol% (away from the percolation threshold) of MWC...

The objective of the present study is to systematically characterize a nonlinear viscoelastic behavior of petroleum jelly in large amplitude oscillatory shear flow fields correspondent to the rubbing condition onto the human body. With this aim, using a strain-controlled rheometer, the dynamic viscoelastic properties of commercially available petroleum jelly have been measured at 37oC (body tem...

Biaxial strain is known to induce ferroelectricity in thin films of nominally nonferroelectric materials such as SrTiO3. By a direct comparison of the strained and strain-free SrTiO3 films using dielectric, ferroelectric, Raman, nonlinear optical and nanoscale piezoelectric property measurements, we conclude that all SrTiO3 films and bulk crystals are relaxor ferroelectrics, and the role of str...

We show how strain stiffening affects the elastic response to internal forces, caused either by material defects and inhomogeneities or by active forces that molecular motors generate in living cells. For a spherical force dipole in a material with a strongly nonlinear strain energy density, strains change sign with distance, indicating that, even around a contractile inclusion or molecular mot...

In the presented paper, the governing equations of a vibratory beam with moderately large deflection are derived using the first order shear deformation theory. The beam is homogenous, isotropic and it is subjected to the dynamic transverse and axial loads. The kinematic of the problem is according to the Von-Karman strain-displacement relations and the Hook's law is used as the constitutive eq...

conclusions pci was accompanied by some improvement in left atrial deformation indices as assessed by tissue doppler imaging. revascularization can, therefore, improve patient outcome. results regarding changes in left trial functional parameters after pci, those such as the strain of the septal wall and the anterior and inferior walls and the strain rate of the anterior and lateral walls signi...

BACKGROUND The nonlinear mechanical properties of internal organs and tissues may be measured with unparalleled precision using ultrasound imaging with phase-sensitive speckle tracking. The many potential applications of this important noninvasive diagnostic approach include measurement of arterial stiffness, which is associated with numerous major disease processes. The accuracy of previous ul...

In this paper, the first-order shear deformation theory is used to derive theoretical formulations illustrating the nonlinear dynamic response of functionally graded porous plates under thermal and mechanical loadings supported by Pasternak’s model of the elastic foundation. Two types of porosity including evenly distributed porosities (Porosity-I) and unevenly distributed porosities (Porosity-...

The aim of this article is to analyze nonlinear electro-magneto vibration of a double-piezoelectric composite microplate-system (DPCMPS) pursuant to the nonlocal piezoelasticity theory. The two microplates are assumed to be connected by an enclosing elastic medium, which is simulated by the Pasternak foundation. Both of piezoelectric composite microplates are made of poly-vinylidene fluoride (P...