Poisson's ratios of lightweight transversally isotropic foam plastics subjected to deformation perpendicular to the rise direction

1992 ◽  
Vol 27 (4) ◽  
pp. 463-470 ◽  
Author(s):  
I. V. Beverte
Keyword(s):  
Transversally Isotropic ◽  
Poisson's Ratios ◽  
Poisson’S Ratios ◽  
Foam Plastics ◽  
Isotropic Foam ◽  
Rise Direction

scholarly journals Giant negative Poisson’s ratio in two-dimensional V-shaped materials

2021 ◽  
Author(s):  
Xikui Ma ◽  
Jian Liu ◽  
Yingcai Fan ◽  
Weifeng Li ◽  
Jifan Hu ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Two Dimensional ◽  
Auxetic Materials ◽  
Negative Poisson's Ratio ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Two-dimensional (2D) auxetic materials with exceptional negative Poisson’s ratios (NPR) are drawing increasing interest due to the potentials in medicine, fasteners, tougher composites and many other applications. Improving the auxetic...

Continuum Description of the Time- and Strain-Dependent Poisson’s Ratio of Ligament Under Finite Deformation

2013 ◽  
Author(s):  
Aaron M. Swedberg ◽  
Shawn P. Reese ◽  
Steve A. Maas ◽  
Benjamin J. Ellis ◽  
Jeffrey A. Weiss
Keyword(s):  
Large Scale ◽  
Mechanical Response ◽  
Tensile Deformation ◽  
Large Strain ◽  
Fiber Direction ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Poisson's Ratios ◽  
Poisson’S Ratios ◽  
Strain Dependent

Ligament volumetric behavior controls fluid and thus nutrient movement as well as the mechanical response of the tissue to applied loads. The reported Poisson’s ratios for tendon and ligament subjected to tensile deformation loading along the fiber direction are large, ranging from 0.8 ± 0.3 in rat tail tendon fascicles [1] to 2.98 ± 2.59 in bovine flexor tendon [2]. These Poisson’s ratios are indicative of volume loss and thus fluid exudation [3,4]. We have developed micromechanical finite element models that can reproduce both the characteristic nonlinear stress-strain behavior and large, strain-dependent Poisson’s ratios seen in tendons and ligaments [5], but these models are computationally expensive and unfeasible for large scale, whole joint models. The objectives of this research were to develop an anisotropic, continuum based constitutive model for ligaments and tendons that can describe strain-dependent Poisson’s ratios much larger than the isotropic limit of 0.5. Further, we sought to demonstrate the ability of the model to describe experimental data, and to show that the model can be combined with biphasic theory to describe the rate- and time-dependent behavior of ligament and tendon.

Carbon nanotube films change Poisson’s ratios from negative to positive

2010 ◽  
Vol 97 (6) ◽  
pp. 061909 ◽  
Author(s):  
Yin Ji Ma ◽  
Xue Feng Yao ◽  
Quan Shui Zheng ◽  
Ya Jun Yin ◽  
Dong Jie Jiang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Poisson's Ratios ◽  
Poisson’S Ratios ◽  
Nanotube Films

scholarly journals Theoretical and practical differences between creep and relaxation Poisson’s ratios in linear viscoelasticity

2015 ◽  
Vol 19 (4) ◽  
pp. 537-555 ◽  
Author(s):  
Abudushalamu Aili ◽  
Matthieu Vandamme ◽  
Jean-Michel Torrenti ◽  
Benoit Masson
Keyword(s):  
Linear Viscoelasticity ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Testing and Simulation of Stress-Stiffening Extreme Poisson’s Ratio Twisted Fiber-Reinforced Elastomer Composites

2008 ◽  
Author(s):  
Larry D. Peel ◽  
Madhuri Lingala
Keyword(s):  
Double Helix ◽  
Fiber Bundles ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Morphing Aircraft ◽  
Active Vibration ◽  
Elastomer Composites ◽  
Poisson's Ratios ◽  
Poisson’S Ratios ◽  
Twisted Fiber

Laminates that exhibit high and negative Poisson’s ratios can be used as solid-state actuators, passive and active vibration dampers, and for morphing aircraft structures. Recently, fiber-reinforced elastomer (FRE) laminates have been fabricated that exhibit extreme (high and negative) Poisson’s ratios [1]. The current research explores twisted fiber bundle elastomeric laminates (both single and double helix) which are being investigated using experimentation, linear and non-linear finite element analysis (FEA). Twisted fiber bundles can be made from carbon fibers, fiberglass, etc, but for simplicity the current work uses twisted cotton string. It is observed that uniaxial fiber-reinforced elastomer laminates, where the fibers are twisted as shown in Figure 1, exhibit stress stiffening. Negative Poisson’s ratios may be produced if the fiber bundles have a double helical path as simulated by a series of laminated tubes. Future auxetic FRE laminates may be developed that do experience extreme shear.

Modulation of Abnormal Poisson’s Ratios and Electronic Properties in Mixed-Valence Perovskite Manganite Films

2018 ◽  
Vol 10 (21) ◽  
pp. 18029-18035 ◽  
Author(s):  
Shanquan Chen ◽  
Changxin Guan ◽  
Shanming Ke ◽  
Xierong Zeng ◽  
Chuanwei Huang ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Mixed Valence ◽  
Perovskite Manganite ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Shallow velocity structure and poisson's ratio at the Tarzana, California, strong-motion accelerometer site

1996 ◽  
Vol 86 (6) ◽  
pp. 1704-1713 ◽  
Author(s):  
R. D. Catchings ◽  
W. H. K. Lee
Keyword(s):  
Urban Areas ◽  
Velocity Structure ◽  
Strong Motion ◽  
P Wave ◽  
S Wave ◽  
Near Surface ◽  
Velocity Models ◽  
Wave Velocities ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Abstract The 17 January 1994, Northridge, California, earthquake produced strong ground shaking at the Cedar Hills Nursery (referred to here as the Tarzana site) within the city of Tarzana, California, approximately 6 km from the epicenter of the mainshock. Although the Tarzana site is on a hill and is a rock site, accelerations of approximately 1.78 g horizontally and 1.2 g vertically at the Tarzana site are among the highest ever instrumentally recorded for an earthquake. To investigate possible site effects at the Tarzana site, we used explosive-source seismic refraction data to determine the shallow (<70 m) P-and S-wave velocity structure. Our seismic velocity models for the Tarzana site indicate that the local velocity structure may have contributed significantly to the observed shaking. P-wave velocities range from 0.9 to 1.65 km/sec, and S-wave velocities range from 0.20 and 0.6 km/sec for the upper 70 m. We also found evidence for a local S-wave low-velocity zone (LVZ) beneath the top of the hill. The LVZ underlies a CDMG strong-motion recording site at depths between 25 and 60 m below ground surface (BGS). Our velocity model is consistent with the near-surface (<30 m) P- and S-wave velocities and Poisson's ratios measured in a nearby (<30 m) borehole. High Poisson's ratios (0.477 to 0.494) and S-wave attenuation within the LVZ suggest that the LVZ may be composed of highly saturated shales of the Modelo Formation. Because the lateral dimensions of the LVZ approximately correspond to the areas of strongest shaking, we suggest that the highly saturated zone may have contributed to localized strong shaking. Rock sites are generally considered to be ideal locations for site response in urban areas; however, localized, highly saturated rock sites may be a hazard in urban areas that requires further investigation.

Expansion potential of skin grafts with novel I-shaped auxetic incisions

2021 ◽  
Author(s):  
Vivek Gupta ◽  
Arnab Chanda
Keyword(s):  
Skin Grafting ◽  
Burn Injuries ◽  
Skin Grafts ◽  
Severe Burn ◽  
Thickness Skin ◽  
Split Thickness Skin Grafting ◽  
Shape Pattern ◽  
Severe Burn Injuries ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Abstract Severe burn injures lead to millions of fatalities every year due to lack of skin replacements. While skin is a very limited and expensive entity, split thickness skin grafting, which involves the projection of a parallel incision pattern on a small section of healthy excised skin, is typically employed to increase the expansion and cover a larger burn site. To date, the real expansion capacity of such grafts are low (<3 times) and insufficient for treatment of severe burn injuries. In this study, novel I-shaped auxetic incision patterns, which are known to exhibit high negative Poisson’s ratios, have been tested on the skin to investigate their expansion potential. Fourteen two-layer skin graft models with varying incision pattern parameters (i.e., length, spacing, and orientation) were developed using finite element modelling and tested under uniaxial and biaxial tensile loads. The Poisson’s ratio, meshing ratios, and induced stresses were quantified across all models. Graft models tested uniaxially along the orthogonal directions indicated opposite trends in generated Poisson’s ratios, as the length of the I-shape incisions were increased. Biaxially, with a symmetric and closely spaced I-shape pattern, graft meshing ratios up to 15.65 were achieved without overstressing the skin. Overall, the findings from the study indicated that expansion potentials much higher than that of traditional skin grafts can be achieved with novel I-shaped auxetic skin grafts, which would be indispensable for covering large wounds in severe burn injuries.

scholarly journals Mechanical properties and fracture dynamics of silicene membranes

2014 ◽  
Vol 16 (36) ◽  
pp. 19417-19423 ◽  
Author(s):  
T. Botari ◽  
E. Perim ◽  
P. A. S. Autreto ◽  
A. C. T. van Duin ◽  
R. Paupitz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Temperature Dependence ◽  
Young’S Modulus ◽  
Edge Effects ◽  
Critical Strain ◽  
Young's Modulus ◽  
Stress Distributions ◽  
Fracture Dynamics ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

A thorough study on the mechanical properties of silicene membranes. Young's modulus, Poisson's ratios, critical strain values, edge effects, dynamics of edge reconstructions, temperature dependence and stress distributions were investigated.

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