Effect of Filler Morphology and Distribution State on the Linear and Nonlinear Mechanical Behavior of Nanofilled Elastomers

2017 ◽  
Vol 50 (17) ◽  
pp. 6369-6384 ◽  
Author(s):  
Mathieu Tauban ◽  
Jean-Yves Delannoy ◽  
Paul Sotta ◽  
Didier R. Long
Keyword(s):  
Mechanical Behavior ◽  
Nonlinear Mechanical ◽  
Linear And Nonlinear ◽  
Distribution State

BIOMECHANICAL CHARACTERIZATION OF NORMAL AND PROLAPSED VAGINAL TISSUE SURROGATES

2018 ◽  
Vol 18 (03) ◽  
pp. 1750100 ◽  
Author(s):  
ARNAB CHANDA ◽  
ZACHARY FLYNN ◽  
VINU UNNIKRISHNAN
Keyword(s):  
Mechanical Behavior ◽  
Experimental Testing ◽  
Low Cost ◽  
Vaginal Tissue ◽  
Novel Materials ◽  
Tissue Interactions ◽  
Surgical Suture ◽  
Nonlinear Mechanical ◽  
Implantation Techniques ◽  
Linear And Nonlinear

In the recent years, poorly evaluated gynecological surgeries and urogynecological mesh implantations have been affecting millions of women in the US and across the globe. These failed surgeries could be mainly attributed to the nonavailability of vaginal tissues (due to ethical and biosafety issues), which does not allow any experimental testing of operation and mesh implantation techniques before an actual surgery. A surrogate which behaves biomechanically like the human vaginal tissue would be indispensable for simulating surgical suture of vaginal tissues in prolapse surgery, hysterectomy or surgery during traumatic child births (such as Cesarean). Also, vaginal tissue surrogates simulating the various prolapse conditions (such as vaginal tissue stiffening) would be very useful to evaluate tissue modifications due to prolapse, and also mesh and vaginal tissue interactions. In the current work, a low cost four-part silicone-based material was developed, which precisely simulates the linear and nonlinear mechanical behavior of the normal human vaginal tissue. Additionally, a range of four-part silicone-based novel materials were developed which precisely mimics the mechanical behavior of stiffened vaginal tissues at different degrees of prolapse. The linear and nonlinear mechanical behavior of all such novel materials were characterized using elastic and hyperelastic formulations. Such precisely characterized normal and prolapsed vaginal tissue surrogates have not been developed anywhere to date as per the best of our knowledge and would be clinically helpful for gynecological surgical planning in the future.

scholarly journals Material properties and effect of preconditioning of human sclera, optic nerve, and optic nerve sheath

2021 ◽  
Author(s):  
Joseph Park ◽  
Andrew Shin ◽  
Somaye Jafari ◽  
Joseph L. Demer
Keyword(s):  
Optic Nerve ◽  
Mechanical Behavior ◽  
Material Properties ◽  
Biomechanical Properties ◽  
Ocular Tissues ◽  
Tangent Moduli ◽  
Nonlinear Mechanical ◽  
Human Eyes ◽  
Range Of Variation ◽  
Great Stress

AbstractThe optic nerve (ON) is a recently recognized tractional load on the eye during larger horizontal eye rotations. In order to understand the mechanical behavior of the eye during adduction, it is necessary to characterize material properties of the sclera, ON, and in particular its sheath. We performed tensile loading of specimens taken from fresh postmortem human eyes to characterize the range of variation in their biomechanical properties and determine the effect of preconditioning. We fitted reduced polynomial hyperelastic models to represent the nonlinear tensile behavior of the anterior, equatorial, posterior, and peripapillary sclera, as well as the ON and its sheath. For comparison, we analyzed tangent moduli in low and high strain regions to represent stiffness. Scleral stiffness generally decreased from anterior to posterior ocular regions. The ON had the lowest tangent modulus, but was surrounded by a much stiffer sheath. The low-strain hyperelastic behaviors of adjacent anatomical regions of the ON, ON sheath, and posterior sclera were similar as appropriate to avoid discontinuities at their boundaries. Regional stiffnesses within individual eyes were moderately correlated, implying that mechanical properties in one region of an eye do not reliably reflect properties of another region of that eye, and that potentially pathological combinations could occur in an eye if regional properties are discrepant. Preconditioning modestly stiffened ocular tissues, except peripapillary sclera that softened. The nonlinear mechanical behavior of posterior ocular tissues permits their stresses to match closely at low strains, although progressively increasing strain causes particularly great stress in the peripapillary region.

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