scholarly journals Modelling of Auxetic Woven Structures for Composite Reinforcement

Textiles ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 1-15
Author(s):  
Shivangi Shukla ◽  
Bijoya Kumar Behera ◽  
Rajesh Kumar Mishra ◽  
Martin Tichý ◽  
Viktor Kolář ◽  
...  
Keyword(s):  
Analytical Model ◽  
Poisson’S Ratio ◽  
Axial Strain ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
Actual Performance ◽  
Bending Modulus ◽  
Woven Structures ◽  
Error Percentage ◽  
Composite Reinforcement

The current research is focused on the design and development of auxetic woven structures. Finite element analysis based on computational modeling and prediction of axial strain as well as Poisson’s ratio was carried out. Further, an analytical model was used to calculate the same parameters by a foldable zig-zag geometry. In the analytical model, Poisson’s ratio is based on the crimp percentage, bending modulus, yarn spacing, and coefficient of friction. In this yarn, properties and fabric parameters were also considered. Experimental samples were evaluated for the actual performance of the defined auxetic material. Auxetic fabric was developed with foldable strips created in a zig-zag way in the vertical (warp) direction. It is based on the principle that when the fabric is stretched, the unfolding of the folds takes place, leading to an increase in transverse dimensions. Both the analytical and computational models gave close predictions to the experimental results. The fabric with foldable strips created in a zig-zag way in the vertical (warp) direction produced negative Poisson’s ratio (NPR), up to 8.7% of axial strain, and a maximum Poisson’s ratio of −0.41 produced at an axial strain of around 1%. The error percentage in the analytical model was 37.14% for the experimental results. The computational results also predict the Poisson’s ratio with an error percentage of 22.26%. Such predictions are useful for estimating the performance of auxetic woven structures in composite reinforcement. The auxetic structure exhibits remarkable stress-strain behavior in the longitudinal as well as transverse directions. This performance is useful for energy absorption in composite reinforcement.

scholarly journals 4D Printing of NiTi Auxetic Structure with Improved Ballistic Performance

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 745
Author(s):  
Hany Hassanin ◽  
Alessandro Abena ◽  
Mahmoud Ahmed Elsayed ◽  
Khamis Essa
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Analytical Model ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
4D Printing ◽  
Auxetic Structures ◽  
Negative Poisson's Ratio ◽  
The Impact ◽  
Auxetic Structure

Auxetic structures have attracted attention in energy absorption applications owing to their improved shear modulus and enhanced resistance to indentation. On the other hand, four-dimensional (4D) printing is an emerging technology that is capable of 3D printing smart materials with additional functionality. This paper introduces the development of a NiTi negative-Poisson’s-ratio structure with superelasticity/shape memory capabilities for improved ballistic applications. An analytical model was initially used to optimize the geometrical parameters of a re-entrant auxetic structure. It was found that the re-entrant auxetic structure with a cell angle of −30° produced the highest Poisson’s ratio of −2.089. The 4D printing process using a powder bed fusion system was used to fabricate the optimized NiTi auxetic structure. The measured negative Poisson’s ratio of the fabricated auxetic structure was found in agreement with both the analytical model and the finite element simulation. A finite element model was developed to simulate the dynamic response of the optimized auxetic NiTi structure subjected to different projectile speeds. Three stages of the impact process describing the penetration of the top plate, auxetic structure, and bottom plate have been identified. The results show that the optimized auxetic structures affect the dynamic response of the projectile by getting denser toward the impact location. This helped to improve the energy absorbed per unit mass of the NiTi auxetic structure to about two times higher than that of the solid NiTi plate and five times higher than that of the solid conventional steel plate.

Characterization of the Mechanical Properties of Monolayer Molybdenum Disulfide Nanosheets Using First Principles

2013 ◽  
Vol 4 (3) ◽  
Author(s):  
R. Ansari ◽  
S. Malakpour ◽  
M. Faghihnasiri ◽  
S. Ajori
Keyword(s):  
Mechanical Properties ◽  
Molybdenum Disulfide ◽  
Poisson’S Ratio ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Axial Strain ◽  
Poisson's Ratio ◽  
Generalized Gradient ◽  
Shear Moduli ◽  
Molybdenum Disulfide Nanosheets

Recently, synthesized inorganic two-dimensional monolayer nanostructures are very promising to be applied in electronic devices. This article explores the mechanical properties of a monolayer molybdenum disulfide (MoS2) including Young's bulk and shear moduli and Poisson's ratio by applying density functional theory (DFT) calculation based on the generalized gradient approximation (GGA). The results demonstrate that the elastic properties of MoS2 nanosheets are less than those of graphene and hexagonal boron-nitride (h-BN) nanosheets. However, their Poisson's ratio is found to be higher than that of graphene and h-BN nanosheet. It is also observed that due to the special structure of MoS2, the thickness of nanosheet changes when the axial strain is applied.

Poisson's ratio of plywood measured by tension test

Holzforschung ◽  
2009 ◽  
Vol 63 (5) ◽  
Author(s):  
Hiroshi Yoshihara
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Poisson’S Ratio ◽  
Tension Test ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
Element Analysis ◽  
Young’S Moduli ◽  
Tension Tests ◽  
Finite Element Calculations

Abstract In this research, Poisson's ratio of plywood as obtained by a tension test was examined by varying the width of the specimen. The tension tests were conducted on five-plywood of lauan (Shorea sp.) with various widths, and Young's moduli and Poisson's ratios of the specimens were measured. Finite element calculations were independently conducted. A comparison of the experimental results with those of finite element analysis revealed that Young's modulus could be obtained properly when the width of the plywood strip varied. In contrast, the width of the plywood strip should be large enough to determine Poisson's ratio properly.

Temperature Buildup in Bonded Rubber Blocks Due to Hysteresis

1977 ◽  
Vol 50 (1) ◽  
pp. 186-193
Author(s):  
B. P. Holownia
Keyword(s):  
Temperature Distribution ◽  
Cyclic Loading ◽  
Theoretical Analysis ◽  
Poisson’S Ratio ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
The Third ◽  
Significant Figure ◽  
Rubber Block

Abstract The comparison between theoretical and experimental results of the temperature distribution in bonded cyclindrical rubber blocks due to compressive cyclic loading was largely dependent on the value of Poisson's ratio. It was found that, for thin rubber blocks (D/h>6), the third significant figure in the value of v appreciably altered the temperature distribution, while for thick blocks (D/h<4), the same change in v had much smaller effect on the temperature distribution within the rubber block. The theoretical analysis used in the paper can easily be adapted for blocks of different geometries, and hence the temperature distribution within a desirable limit can be achieved by changing the geometry of the rubber block.

MICROSCOPIC PROPERTIES OF BONE TISSUE USING MEASUREMENT SYSTEM WITH NANO-RESOLUTION

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4697-4702
Author(s):  
JUNGHWA HONG ◽  
YOUNG-WHAN PARK ◽  
HEE-SUNG CHA ◽  
GON KHANG
Keyword(s):  
Elastic Modulus ◽  
Measurement Error ◽  
Measurement System ◽  
Poisson’S Ratio ◽  
Axial Strain ◽  
Biomechanical Properties ◽  
Poisson's Ratio ◽  
System Configuration ◽  
Skeletal System ◽  
The Mean

To understand the physiology and pathology of human skeletal system, the accurate measurement of microscopic biomechanical properties of bone is an important works. In this study, a measurement system of the Poisson's ratio with a sub-nano resolution was developed. The resulting resolution of the system was 0.3 nm, which was 0.1% of the measurement error for this system configuration. Using this measurement system, actual tests were performed to check the capability of the measurement system. Cubic bone specimens with a dimension of 300 μm were loaded up to an axial strain of 0.5%, which is within the elastic range of the specimens. The mean elastic modulus and the Poisson's ratio of bovine femoral cortical bone measured in this study were 14.42 GPa ( SD ± 0.6179) and 0.265 ( SD ± 0.0125) respectively. The developed system will be useful to understand the biomechanics of bones for modeling the mechanobiological bone system.

An approximate analysis of infinitesimal deformations of bonded elastic mounts

1988 ◽  
Vol 23 (3) ◽  
pp. 115-120 ◽  
Author(s):  
M H B M Shariff
Keyword(s):  
Explicit Form ◽  
Elastic Material ◽  
Poisson’S Ratio ◽  
Shape Factor ◽  
Theoretical Solution ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
Approximate Analysis ◽  
Theoretical Investigations ◽  
Infinitesimal Deformations

An approximate simple theoretical solution is developed for infinitesimal plane and axisymmetric strain deformations for blocks of elastic material with Poisson's ratio between 0 and 0.5 bonded to rigid end plates. The explicit form of solution, developed for shape factor, S, between 0 and ∞, is easy to use and compares well with published experimental results. It is also comparable with previous theoretical investigations and expected behaviour.

scholarly journals An Experimental Study on the Mechanical Properties of High-Temperature Granite under Natural Cooling and Water Cooling

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yanan Gao ◽  
Yunlong Wang ◽  
Taiping Lu ◽  
Liuzhou Li ◽  
Jinwen Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
High Temperature ◽  
Poisson’S Ratio ◽  
Heating Temperature ◽  
Axial Strain ◽  
Peak Stress ◽  
Poisson's Ratio ◽  
Water Cooling ◽  
Cooling Methods

With the further development of deep rock mechanics engineering, such as the exploitation and utilization of geothermal resources, the exploitation of deep mineral resources, and the safe disposal of nuclear waste, the study of mechanical properties of deep high-temperature rock is gaining the attention of the researchers. However, not only the high temperature but also the cooling condition/method that will be used in the construction such as drilling cooling will also greatly affect the mechanical properties of the rock. In this paper, the mechanical behaviour and the evolution of the mechanical properties of the high-temperature (600°C–1,000°C) granite under different cooling methods are studied. The following conclusions can be obtained: (1) The peak stress of the granite decreases with the heating temperature. Compared with natural cooling, water cooling has a more significant effect on strength degradation. (2) The increase of the heating temperature increases the maximum axial strain of the granite. The water cooling method more greatly induces the maximum axial strain of granite than the natural cooling. The maximum axial strain of the specimen under the water cooling reaches 117.3% of that under natural cooling (800°C). (3) The elastic modulus of the granite decreases with the heating temperature. Water cooling will have a stronger effect on the reduction of the elastic modulus than natural cooling. The maximum difference value (2.02 GPa) of the elastic modulus under the different cooling methods occurs at the temperature of 800°C. (4) Poisson’s ratio of the granite increases with heating temperature, and the cooling method does not have an evident effect on it. The relationship between Poisson’s ratio and the heating temperature under different cooling methods can be described using the linear model. (5) According to the influence of the temperature on the peak stress, the elastic modulus, and Poisson’s ratio, the heating temperature domain can be divided into the unapparent zone, the significant zone, and the mitigation zone. (6) The thermal stress due to the nonuniform temperature field and the different thermal expansion coefficients is incompatible. Such incompatibility stresses the essences of the degradation of the mechanical properties of the granite.

scholarly journals Effect of Different Yarn Combinations on Auxetic Properties of Plied Yarns

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mine Akgun ◽  
Recep Eren ◽  
Fatih Suvari ◽  
Tugba Yurdakul
Keyword(s):  
Polyvinyl Chloride ◽  
Poisson’S Ratio ◽  
Tensile Modulus ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
Yarn Twist ◽  
Twist Level ◽  
Negative Poisson's Ratio ◽  
Yarn Structure ◽  
Plied Yarn

Abstract This study presents the effects of a novel plied yarn structure consisting of different yarn components and yarn twist levels on the Poisson's ratio and auxetic behavior of yarns. The plied yarn structures are formed with bulky and soft yarn components (helical plied yarn [HPY], braided yarn, and monofilament latex yarn) and stiff yarn components (such as high tenacity [HT] and polyvinyl chloride [PVC]-coated polyester yarns) to achieve auxetic behavior. Experimental results showed that as the level of yarn twist increased, the Poisson's ratios and the tensile modulus values of the plied yarns decreased, but the elongation values increased. A negative Poisson's ratio (NPR) was obtained in HT–latex and PVC–latex plied yarns with a low twist level. The plied yarns formed with braid–HPY and braid–braid components gave partial NPR under tension. A similar result was achieved for yarns with HT–latex and PVC–latex components. Since partial NPR was seen in novel plied yarns with braided and HPY components, it is concluded that yarns formed with bulky–bulky yarn components could give an auxetic performance under tension.

Apparent Poisson’s Ratio for Fe-Ga Alloy Single Crystal due to Magnetostriction

2018 ◽  
Vol 941 ◽  
pp. 879-883 ◽  
Author(s):  
Masaki Fujita ◽  
Takehito Ikeuchi ◽  
Akihiro Koyama ◽  
Muneyuki Imafuku ◽  
Shun Fujieda ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Poisson’S Ratio ◽  
Axial Strain ◽  
Magnetic Domain ◽  
Strain Analysis ◽  
Poisson's Ratio ◽  
Zero Magnetic Field ◽  
Actual Behavior ◽  
X Ray Diffraction

Fe-Ga alloys are used for practical magnetostrictive materials. The understanding of mechanical properties under magnetic field is very important for their application to vibration power generation devices. Especially, Poisson’s ratio is one of key parameters because it is strongly related with the volume change of materials. In the study, we investigated actual behavior of Poisson’s ratio due to magnetostriction, instead of just the mechanical one. The sample was cube-oriented Fe-18mol%Ga single crystal disc. Static magnetic fields were applied in various directions parallel to (001). Strain values in various directions were measured by strain gauge and X-ray diffraction. And then, tri-axial strain analysis for single crystal was carried out. Theoretically, Poisson’s ratio due to magnetostriction is known to be 0.5, (volume conservative), value is close to the mechanical one, 0.45. On the other hand, we found that Poisson’s ratio exhibits anisotropic behavior despite the elastic constants are equivalent in [010] and [001]. This phenomenon is attributable to the magnetic domain structure under zero magnetic field. In this presentation, we will discuss this apparent Poisson’s ratio considering the volume strain and magnetostriction comprehensively.

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