Viscoelastic and Poisson’s ratio characterization of asphalt materials: critical review and numerical simulations

2016 ◽  
Vol 50 (1) ◽  
Author(s):  
Qazi Aurangzeb ◽  
Hasan Ozer ◽  
Imad L. Al-Qadi ◽  
Harry H. Hilton
Keyword(s):  
Numerical Simulations ◽  
Critical Review ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Asphalt Materials

Simultaneous Determination of E, G and ν of Soft Hydrogels Using Theory of Elasticity

2009 ◽  
Author(s):  
Uday Chippada ◽  
Xue Jiang ◽  
Lulu Li ◽  
Rene Schloss ◽  
Bernard Yurke ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Theory Of Elasticity ◽  
Complete Characterization ◽  
Poisson's Ratio ◽  
Force Microscopy ◽  
Cellular Processes ◽  
Atomic Force ◽  
Significant Research

Hydrogels have been used as substrates by many researchers in the study of cellular processes. The mechanical properties of these gels play a significant role in the growth of the cells. Significant research using several methods like compression, indentation, atomic force microscopy and manipulation of beads has been performed in the past to characterize the stiffness of these substrates. However, most of the methods employed assume the gel to be incompressible, with a Poisson’s ratio of 0.5. However, Poisson’s ratio can differ from 0.5. Hence, a more complete characterization of the elastic properties of hydrogels requires that one experimentally obtain the value of at least two of the three quantities: Poisson’s ratio, shear modulus, and elastic modulus.

Close-in blast resistance of large-scale auxetic re-entrant honeycomb sandwich panels

2020 ◽  
pp. 109963622097545
Author(s):  
Dulara Kalubadanage ◽  
Alex Remennikov ◽  
Tuan Ngo ◽  
Chang Qi
Keyword(s):  
Numerical Simulations ◽  
Poisson’S Ratio ◽  
Blast Loading ◽  
Steel Plates ◽  
Poisson's Ratio ◽  
Deformation Pattern ◽  
Negative Poisson’S Ratio ◽  
Blast Loads ◽  
Protective System ◽  
Negative Poisson's Ratio

The protection of critical infrastructure, including government buildings, airports, religious buildings, military buildings and military vehicles, which are at risk to blast loads, has become important due to increasing terrorist activities in recent years. Sacrificial cladding systems based on negative Poisson’s ratio core topologies have recently received more attention as a protective technology due to its excellent energy absorption capability. In this study, field blast tests were performed on metallic re-entrant honeycomb-cored sacrificial cladding systems as protective structures for steel plate structures. This study focused on the near-field blast loading conditions where liquid Nitromethane (NM) spherical charges were detonated in close proximity to the main structure. Two 6 mm thick mild steel plates and two steel plates protected with re-entrant honeycomb-cored sacrificial cladding systems were among the specimens tested. The proposed auxetic cladding system was fabricated from aluminium sheets using a novel in-house built folding machine. Numerical simulations were conducted utilising LS-DYNA software and the Blast Impact Impulse Model (BIIM). The results obtained from the numerical simulations are in good agreement with the experimental results. It was found that the deformation pattern of the sacrificial auxetic cladding system varies with the intensity of the blast loading, and there is a limit at which the proposed protective system ceases to effectively absorb the applied blast loading. The variation of negative Poisson’s ratio of the system with blast loading was studied. It was found that the auxetic cladding system could become a solid projectile leading to damage amplification for very close-range blast loads due to rapid densification of the auxetic core. The proposed cladding systems with narrow re-entrant angles performed well under blast loads due to relatively low stiffness of the panels. Finally, the optimisation study was performed for the protective system. Overall, the experimental and numerical results assure that auxetic-based cladding systems are suitable for applications requiring blast protection such as armoured vehicles and critical physical infrastructure but need to be carefully designed for the given blast threat to prevent overloading of the protected structures.

Design and fabrication of auxetic warp-knitted structures with a rotational hexagonal loop

2016 ◽  
Vol 86 (20) ◽  
pp. 2151-2157 ◽  
Author(s):  
Pibo Ma ◽  
Yuping Chang ◽  
Gaoming Jiang
Keyword(s):  
Poisson’S Ratio ◽  
Rotation Angle ◽  
Hexagonal Structure ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Two Dimensional ◽  
Auxetic Structures ◽  
Negative Poisson's Ratio ◽  
Novel Structures

In this paper, the design, manufacturing and characterization of two-dimensional warp-knitted textiles with auxetic performance is reported. Four warp-knitted structures based on a rotational hexagonal structure are produced, and these structures can lead to a negative Poisson’s ratio mathematically. The testing results have confirmed that the knitting structure of the front bar, as well as let-off values of the front bar’s chain parts, has a great effect, and auxetic properties of the warp-knitted textiles have a complicated relationship with the rotation angle. These novel structures can expand the applied area of auxetic structures.

scholarly journals Recommendation of RILEM TC 237-SIB on complex Poisson’s ratio characterization of bituminous mixtures

2017 ◽  
Vol 50 (2) ◽  
Author(s):  
A. Graziani ◽  
H. Di Benedetto ◽  
D. Perraton ◽  
C. Sauzéat ◽  
B. Hofko ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Bituminous Mixtures ◽  
Complex Poisson’S Ratio

Influence of the Poisson's ratio on the efficiency of viscoelastic damping treatments

2021 ◽  
Vol 263 (3) ◽  
pp. 3790-3794
Author(s):  
Lucie Rouleau ◽  
Isadora Ruas Henriques ◽  
Jean-François Deü
Keyword(s):  
Poisson’S Ratio ◽  
Poisson Ratio ◽  
Young Modulus ◽  
Indirect Measurement ◽  
Poisson's Ratio ◽  
Viscoelastic Layer ◽  
Temperature Dependent ◽  
Complex Shear ◽  
Damping Treatments

An efficient way of mitigating noise and vibration is to embed viscoelastic patches into the host structure. Viscoelastic properties are of significant importance in determining the performance of the passive damping treatment. The behaviour of homogeneous isotropic materials is described by two elastic constants (generally the Young modulus and the Poisson ratio, or the shear and bulk moduli), which are frequency- and temperature-dependent in the case of viscoelastic materials. In practice, the Poisson's ratio is often considered as independent of temperature and frequency. One goal of this work is to numerically evaluate the validity of this assumption and its limitations (frequency range, thickness of the viscoelastic layer). To this end, a thermo-mechanical characterization of a viscoelastic material is carried out by dynamic measurements of the complex shear and bulk moduli, allowing the indirect measurement of the frequency- and temperature-dependent Poisson's ratio. Moreover, the measurements of the Poisson's ratio (direct or indirect) can lead to considerable uncertainties. For instance, large discrepancies have been observed when characterizing the Poisson's ratio of polymer foams. Another goal of this work is to investigate the influence of those uncertainties on the dynamic response of a damped structure.

Design, preparation, and characterization of auxetic weft backed weave fabrics based on Miura origami structure

2021 ◽  
pp. 004051752110505
Author(s):  
Qiaoli Xu ◽  
Longxin Gu ◽  
Gui Liu ◽  
Zhuoran Liu ◽  
Dongdong Lu ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Physical Map ◽  
Structure Type ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Auxetic Materials ◽  
Out Of Plane ◽  
Weaving Technology ◽  
Negative Poisson's Ratio

The metamaterials with negative Poisson’s ratio are called auxetic materials, which as a branch of metamaterials has drawn a lot of attention in many areas. Existing auxetic knitting textiles combine flexibility and auxeticity, however the loose structure has been a main disadvantage for its application. In this study, we fabricated Miura origami structure fabrics by weaving technology in order to acquire more stable auxetic textiles. The results show that using the combination of fabric structure type and elastic yarns, an origami structure can be realized in a jacquard loom. In the Miura origami structure, the crease pattern can be separated into three parts, unfolding areas, convex areas, and concave areas. One warp system and two weft systems are compounded together, in which a weft backed weave is used to get elastic floats in the convex and concave areas, and to make the fabrics bend to the concave side. The physical map showed that the fabrics had a clear Miura origami structure and the unfolding areas were flat and even. On the basis of the designed geometric pattern, weft backed weaves can be used to construct different folded areas, spandex wrapped PET (Polyester) and inelastic PET are selected as two weft systems for weaving. Meanwhile, the Miura origami fabrics exhibit distinct in-plane negative Poisson’s ratio and out-of-plane positive Poisson’s ratio. Apart from the Miura origami structure, other origami and paper-cut structures can be realized using this method, and these special auxetic textiles have potential in protective cloths, ornamented textiles, wearable devices, and flexible sensors.

Development and auxetic characterization of 3D composites produced with newly-designed multi-cell flat-knitted spacer fabrics

2020 ◽  
pp. 152808372097169
Author(s):  
Zahra Moshtaghian ◽  
Hossein Hasani ◽  
Mohammad Zarrebini ◽  
Mohammad Pourheidar Shirazi
Keyword(s):  
Poisson’S Ratio ◽  
Composite Structures ◽  
Compressive Strain ◽  
Poisson's Ratio ◽  
Initial Slope ◽  
Displacement Curve ◽  
3D Composite ◽  
Spacer Fabrics ◽  
Composite Samples

The paper deals with development and characterization of 3D sandwich composite structures reinforced with newly-designed multi-cell flat-knitted spacer fabrics in terms of compressive behaviour and Poisson’s ratio. Multi-cell spacer knitted preforms was produced on a computerized flat knitting machine. 3D composite samples with three different cross-sectional geometries were prepared via vacuum assisted resin transfer moulding method. Quasi-static compressive experiments were carried out on the prepared 3D composite samples. The Poisson’s ratio of re-entrant 3D knitted composite varied between -6 and -1, which clearly points to existence of auxetic behaviour of the samples. The re-entrant 3D composites also demonstrated the highest initial slope and area under the compression force-displacement curve than spear-head or hexagonal composite structures which refer to higher energy absorbing capacity. The Poisson’s ratio of 3D regular hexagonal knitted composites at small strain was usually 4 which gradually decreased to 1.6 as the exerted compressive strain increased. Additionally, 3D spear-head knitted composite having zero Poisson’s ratio was also developed.

scholarly journals The manufacture and characterization of auxetic, self-curling, and self-folding woven fabrics by helical auxetic yarns

2018 ◽  
Vol 50 (1) ◽  
pp. 3-12
Author(s):  
Sai Liu ◽  
Xingxing Pan ◽  
Dongming Zheng ◽  
Gui Liu ◽  
Zhaoqun Du
Keyword(s):  
Poisson’S Ratio ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Poisson's Ratio ◽  
Natural State ◽  
Practical Applications ◽  
Maximum Value ◽  
Auxetic Structures ◽  
The Relationship

Auxetic fabrics with traditional filaments and auxetic structures have been provided by knitting method; however, the auxetic behavior and applicability of woven fabric with auxetic yarns remain to be studied. Thus, the paper aims to present the special characters of woven fabrics with heliacal auxetic yarns. Auxetic yarns with the maximum value of Poisson's ratio −0.88 were used as weft yarns to do the weaving by the semi-automatic loom. Then the properties of the fabrics have been tested and analyzed under tensions of different directions (warp, weft, and diagonal). The results indicated that the fabric presented auxetic effect with the maximum value of Poisson's ratio −0.3 under diagonal tension and also showed self-curling and self-folding behavior in natural state. Moreover, the relationship between properties and fabric weaves was also discussed and analyzed. It is expected that the study of fabrics with helical auxetic yarns could promote the practical applications of auxetic textiles such as the self-folding property for smart cladding materials.

Experimental characterization of the mechanical properties of 3D-printed ABS and polycarbonate parts

2017 ◽  
Vol 23 (4) ◽  
pp. 811-824 ◽  
Author(s):  
Jason T. Cantrell ◽  
Sean Rohde ◽  
David Damiani ◽  
Rishi Gurnani ◽  
Luke DiSandro ◽  
...  
Keyword(s):  
Yield Strength ◽  
Shear Modulus ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Experimental Characterization ◽  
Shear Testing ◽  
Content Type ◽  
Offset Yield Strength ◽  
3D Printed

Purpose This paper aims to present the methodology and results of the experimental characterization of three-dimensional (3D) printed acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) parts utilizing digital image correlation (DIC). Design/methodology/approach Tensile and shear characterizations of ABS and PC 3D-printed parts were performed to determine the extent of anisotropy present in 3D-printed materials. Specimens were printed with varying raster ([+45/−45], [+30/−60], [+15/−75] and [0/90]) and build orientations (flat, on-edge and up-right) to determine the directional properties of the materials. Tensile and Iosipescu shear specimens were printed and loaded in a universal testing machine utilizing two-dimensional (2D) DIC to measure strain. The Poisson’s ratio, Young’s modulus, offset yield strength, tensile strength at yield, elongation at break, tensile stress at break and strain energy density were gathered for each tensile orientation combination. Shear modulus, offset yield strength and shear strength at yield values were collected for each shear combination. Findings Results indicated that raster and build orientations had negligible effects on the Young’s modulus or Poisson’s ratio in ABS tensile specimens. Shear modulus and shear offset yield strength varied by up to 33 per cent in ABS specimens, signifying that tensile properties are not indicative of shear properties. Raster orientation in the flat build samples reveals anisotropic behavior in PC specimens as the moduli and strengths varied by up to 20 per cent. Similar variations were observed in shear for PC. Changing the build orientation of PC specimens appeared to reveal a similar magnitude of variation in material properties. Originality/value This article tests tensile and shear specimens utilizing DIC, which has not been employed previously with 3D-printed specimens. The extensive shear testing conducted in this paper has not been previously attempted, and the results indicate the need for shear testing to understand the 3D-printed material behavior fully.

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