Singularities in auxetic elastic bimaterials

Adam, Mohammed Mustafa; Berger, J. R.; Martin, P. A.

doi:10.1016/j.mechrescom.2012.10.003

Cited by 4 publications

(5 citation statements)

References 29 publications

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“…Auxetics material's tendency to volumetric (rather than distortional deformation) could effectively increase indentation resistance (Figure 6c, Equations (3) and (4)). As Poisson's ratio decreases, so does the stress concentration at a crack's tip, preventing crack propagation and increasing toughness [296,297]. Von Mises and maximum shear stress theory both define failure when distortional strain energy exceeds a maximum value.…”

Section: Appl Sci 2018 8 X 12 Of 31mentioning

confidence: 99%

Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection

Duncan

Shepherd

Moroney³

et al. 2018

Applied Sciences

244

151

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Following high profile, life changing long term mental illnesses and fatalities in sports such as skiing, cricket and American football-sports injuries feature regularly in national and international news. A mismatch between equipment certification tests, user expectations and infield falls and collisions is thought to affect risk perception, increasing the prevalence and severity of injuries. Auxetic foams, structures and textiles have been suggested for application to sporting goods, particularly protective equipment, due to their unique form-fitting deformation and curvature, high energy absorption and high indentation resistance. The purpose of this critical review is to communicate how auxetics could be useful to sports equipment (with a focus on injury prevention), and clearly lay out the steps required to realise their expected benefits. Initial overviews of auxetic materials and sporting protective equipment are followed by a description of common auxetic materials and structures, and how to produce them in foams, textiles and Additively Manufactured structures. Beneficial characteristics, limitations and commercial prospects are discussed, leading to a consideration of possible further work required to realise potential uses (such as in personal protective equipment and highly conformable garments).

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Section: Appl Sci 2018 8 X 12 Of 31mentioning

confidence: 99%

Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection

Duncan

Shepherd

Moroney³

et al. 2018

Applied Sciences

244

151

View full text Add to dashboard Cite

show abstract

“…The increased tendency of materials with a low or negative Poisson's ratio to deform volumetrically, rather than in shear (figure 4), may also increase strength. With lower shear strain, the likelihood of failure close to a crack tip or an ellipsoid reduces, according to Von-Mises, Tresca, and crack propagation theories [379,380]. Without the presence of stress concentrations caused by a crack or ellipsoid, Von-Mises and Tresca criterion are unaffected [368].…”

Section: Auxetic Metamaterialsmentioning

confidence: 99%

Mechanical metamaterials for sports helmets: structural mechanics, design optimisation, and performance

Haid,

Foster,

Hart

et al. 2023

Smart Mater. Struct.

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Sports concussions are a public health concern. Improving helmet performance to reduce concussion risk is a key part of the research and development community response. Head impacts with compliant surfaces that cause long duration moderate or high linear and rotational accelerations are associated with a high rate of clinical diagnoses of concussion. As engineered structures with unusual combinations of properties, mechanical metamaterials are being applied to sports helmets, with the goal of improving impact performance and reducing brain injury risk. Replacing established helmet material (i.e., foam) selection with a metamaterials design approach (structuring material to obtain desired properties) allows development of near optimal properties. Objective functions based on up to date understanding of concussion could be applied to topology optimisation regimes, when designing mechanical metamaterials for helmets. Such regimes balance computational efficiency with predictive accuracy, both of which could be improved under high strains and strain rates to allow helmet modifications as knowledge of concussion develops. Researchers could also share mechanical metamaterial data, topologies and computational models in open, homogenised repositories, to improve the efficiency of their development.

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“…Microstructures and property inhomogeneity of Zr702/TA2/Q345R explosive welding composite plate have been investigated by Ning, and the discontinuities of mechanical properties and chemical components at the interface have been found. In fact, owing to the similarity of Zr702 and TA2, the Zr702/TA2/Q345R composite plate can be classified into mismatched bimaterial system . Normally, the composite material combines two or more different materials so that the finished product can meet the requirements of various working conditions .…”

Section: Introductionmentioning

confidence: 99%

“…In fact, owing to the similarity of Zr702 and TA2, the Zr702/TA2/Q345R composite plate can be classified into mismatched bimaterial system. 5,6 Normally, the composite material combines two or more different materials so that the finished product can meet the requirements of various working conditions. 7,8 Because of the differences of properties between combined materials, the performance of cracks in the composite material has always been the focus of research about the mismatched material.…”

Section: Introductionmentioning

confidence: 99%

“…23 At present, there are many theoretical analyses about cracks normal to interface in the mismatch bimaterial system, 19,24 but these analyses are built on many assumptions, such as ideal interface assumption and continuous distribution assumption. 5,7,13 However, due to the properties and composition of the material at the interface formed by explosive welding are very complicated, these assumptions will be no longer applicable for metal composite plates. Therefore, experimental test is always the main method to study the effect of interface.…”

Section: Introductionmentioning

confidence: 99%

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Investigation on the fatigue crack behavior of Zr702/TA2/Q345R composite plate with a crack normal to interface

Zhou

et al. 2019

Fatigue Fract Eng Mat Struct

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In this paper, the effects of maximum load, load ratio, and average load on fatigue crack propagation of Zr702/TA2/Q345R composite plate with a crack normal to the interface are studied by experiment and finite element method. When crack propagates to the interface from the compliant material side, the crack growth rate decreases to the minimum at first. After crack penetrates through the interface, the fatigue crack growth rate accelerates continuously. When crack propagates to the interface from the stiff material side, the fatigue crack growth rate generally increases with the crack length. Regardless of the direction of crack growth, the increase of load ratio will weaken the difference of crack growth rate near the interface caused by material property mismatch. Finite element results show that elastic modulus mismatch significantly changes the variation of the stress intensity factor amplitude. All results demonstrate that crack growth rate is dependent on the competition of the stress intensity factor amplitude, the fatigue crack growth rate in the corresponding material, and the interface strength.

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Singularities in auxetic elastic bimaterials

Cited by 4 publications

References 29 publications

Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection

Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection

Mechanical metamaterials for sports helmets: structural mechanics, design optimisation, and performance

Investigation on the fatigue crack behavior of Zr702/TA2/Q345R composite plate with a crack normal to interface

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