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Uncertainty Quantification in Composite Structures
Published in Sudip Dey, Tanmoy Mukhopadhyay, Sondipon Adhikari, Uncertainty Quantification in Laminated Composites, 2018
Sudip Dey, Tanmoy Mukhopadhyay, Sondipon Adhikari
In this section, a brief literature review concerning the impact analysis of composites is presented, wherein it can be found that the effect of different parameters such as impact load, impact angle, impact velocity, thickness of laminates and laminate configuration are widely investigated. Different approaches and models are utilised to analyse the impact behaviour of composites. Khashaba and Othman (2017) carried out low-velocity impact testing on the woven CFRE composites considering the effect of temperature. Liao and Liu (2017) presented a FEM based low-velocity impact analysis considering the progressive failure in the laminated composites. Jiang and Hu (2017) performed experimental low-velocity impact analysis of composite structures including auxetic effect. The results show that auxetic composites have better shock resistance and energy absorption capacity as compared to non-auxetic composites. Choi (2017) studied the influence of prestress in composite cylinder subjected to low-velocity impact by using the shear deformation theory, Karman’s large deflection theory and strain displacement relationship. Chen et al. (2017) investigated the effect low-velocity impact on the intra-laminar damage, delamination and strain rate of material in sandwich composite structures.
Overview of Mechanical Behavior of Materials
Published in Heather N. Hayenga, Helim Aranda-Espinoza, Biomaterial Mechanics, 2017
Radu Reit, Matthew Di Prima, Walter E. Voit
Poisson’s ratio, named for the nineteenth-century French mathematician, describes the relationship between the deformation in the loading axis and the deformation normal to the load axis. It can also be thought of as the coefficient of expansion on the transverse axes or the negative ratio of transverse to axial strain. Poisson’s ratio varies between −1.0 and 0.5, the theoretical and practical limits for stable, isotropic, linear elastic materials. Perfectly incompressible materials have Poisson’s ratios of 0.5, and include elastic rubbers. A Poisson’s ratio of 0.5 is density and volume preserving. Thus, the transverse deformation is such that the density is not changed during compression. Most materials have a Poisson’s ratio between 0 and 0.5 and show some signs of densification during compression or tension. Materials such as cork and Styrofoam can have Poisson’s ratios of 0, meaning that there is no change in transverse directions during axial deformation. Materials with negative Poisson’s ratios are called auxetic materials and actually get thicker as they are stretched. Materials such as the synthetic biomaterial Gore-Tex and some tendons [9] show auxetic properties. It is recommended that readers who want to gain a deeper understanding of the complex mechanical properties of materials, delve into more in-depth treatments of these topics and learn about tensor notation, compliance matrices, and advanced mechanics of materials from one of many great references in this area [10].
Metallic Armour Materials and Structures
Published in Paul J. Hazell, Armour, 2023
Auxetic structures are structures that exhibit a negative Poisson’s ratio when applied with a load. That is, when under compression a structure would contract inwards, or when under tension the structure would expand outward (see Figure 7.24). This is counterintuitive as usually one would expect the opposite to occur. However, this behaviour is realized simply through the clever design of an architectured system. Nevertheless, there are several natural auxetic materials that have been discovered in single crystals of arsenic and cadmium as well as other materials. Biological auxetic examples also exist in cow teat skin and cat skin, see (Evans and Alderson, 2000).
A horizontal punch on a layered and orthotropic composite system with negative Poisson’s ratio
Published in Mechanics of Advanced Materials and Structures, 2023
The term “auxetic” was first used by Evans et al. [4] to describe the materials with a negative value of Poisson’s ratio [4]. Isotropic porous materials with a negative value of Poisson's ratios were fabricated by Lakes [5] from conventional open-cell polymer foams by using a method of compression-heating process. The negative Poisson’s ratio of auxetic materials are mainly due to the intertwined deformations of inter-connected members of macro structural forms. Thus, the properties of auxetic cellular materials can be altered if the unit cell architectures are changed. The unusual deformation mode of negative Poisson’s ratio materials exhibit superior properties as compared to conventional materials, such as increased indentation resistance [6–8], improved protective properties [9, 10], higher energy absorption capabilities [11], and better fracture toughness [12, 13]. Auxetic materials are very important in future applications in civil engineering, aeronautical engineering, defense equipment, smart sensors and actuators, filter cleaning technology and biomechanics engineering. In recent years, the number of patent applications and paper publications on auxetic materials has increased significantly.
Nonlinear bending of temperature-dependent FG-CNTRC laminated plates with negative Poisson’s ratio
Published in Mechanics of Advanced Materials and Structures, 2020
Hui-Shen Shen, Xu-Hao Huang, Jian Yang
Recently, fiber reinforced composite (FRC) plate structures have seen a consistent growth in their applications in the sectors of aerospace, aviation, shipbuilding, infrastructure construction etc. Different from the isotropic counterpart, composites always possess complicated mechanical/structural behaviors under external loading actions. Owing to the high specific strength of composites, the design thickness of the plate tends to small. These plates are often subjected to transverse loading and may experience large deflections. In the engineering practice, there often requires prediction of the plate behaviors more accurately in order to suitable applications. Many studies have been carried out on the nonlinear bending behavior of composite laminated plates [1–12]. Auxetic materials are known to exhibit enhancements in many of their key properties for composite materials, including energy absorption, fracture toughness and low velocity impact resistance. The auxetic materials have a wide variety of multifunctional applications, for example, in energy storage, biomedical, acoustics, photonics, and thermal management [13]. There are two ways to construct auxetic structures. One way is to use auxetic metamaterials as sandwich core of plates [14]. Another way is to change the stacking sequence and orientation of the laminates to obtain auxetic laminated plate. The production of larger values of negative Poisson’s ratio (NPR) requires both a particular stacking sequence and that the individual ply material be highly anisotropic [15].
Design and fabrication of novel auxetic weft-knitted fabrics with Kevlar yarns
Published in The Journal of The Textile Institute, 2019
Wanli Xu, Yaxin Sun, King Rafiu Raji, Pibo Ma
Auxetic materials and structures exhibit negative Poisson’s ratio (NPR), they laterally contract when compressed and laterally expend when stretched (Evans, Nkansah, Hutchinson, & Rogers, 1991). These materials and structures have gained attention over the last several years from textile experts, materials engineers and other researchers (Lakes, 1987). This is because of their extraordinary properties, such as antishearing ability, robust fracture strength, excellent mechanical properties, anticompression, good surface fitting ability and high energy absorption properties. Auxetic materials can be widely applied in various areas, including architecture, civil engineering, sports clothing, protection against explosives, high performance equipment, insulation, filters and so on (Pichandi, Rana, Oliveira, Fangueiro, & Xavier, 2014; Simkins, Alderson, Davies, & Alderson, 2005; Wright et al., 2012).