A negative Poisson's ratio suspension jounce bumper

Wang, Yuanlong; Wang, Liangmo; Dong, Zheng; Wang, Tao

doi:10.1016/j.matdes.2016.04.041

Cited by 86 publications

(32 citation statements)

References 23 publications

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“…Analytical formulae were however used to validate FEM suggestions that auxetic honeycombs have higher energy absorption than conventional honeycombs in crushing strength analysis [176]. When varying the impact energy on a jounce bumper [27,177], FEM closely matched experimental values for the material's Poisson's ratio and compressive modulus and the jounce bumper's force and displacement. A subsequent auxetic bumper model showed less vibration in compression than a non-auxetic equivalent.…”

Section: Modelling Auxetic Materials and Structuresmentioning

confidence: 95%

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: Modelling Auxetic Materials and Structuresmentioning

confidence: 95%

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

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“…[56] FE modeling has been used to investigate auxetic structures under impact scenarios, [57] although these examples use flat plates and a high-velocity bullet (150-300 m s À1 ), which is different to the impact scenarios typical of sport, in terms of impactor shape, stiffness, mass, and velocity. Elsewhere, FE modeling has been used to develop an auxetic jounce bumper in the automotive industry, [58] to produce auxetic stents for medicine and predict the indentation response of an auxetic foam in an antivibration glove. [59,60] The accuracy of FE models should be quantified by comparison against experimental data if they are to be used to develop products, such as helmets and other PPE, which require testing of a physical product or prototype, [61] as demonstrated for rotating-unit auxetic structures by Slann et al [62] It is important to validate FE models for scenarios that are representative of those where potential products may be used, such as oblique impacts of helmets or concentrated loads for sporting body padding.…”

mentioning

confidence: 99%

“…[72,73] Specifically designed and intricate auxetic structures can be produced by AM [74] and used in validation experiments for both FE and analytical models. [58,75] Dualmaterial AM auxetic structures have also been developed, where a flexible and a stiffer material can be used in different regions of a structure, allowing greater control over its mechanical properties for the designer. [76] These dual-material structures are more complex to manufacture and, through the application of FE modeling, it may be possible to tailor the geometry of a single-material structure (e.g., rib thickness and taper) to achieve desirable properties at lower manufacturing complexity.…”

mentioning

confidence: 99%

Validation of a Finite Element Modeling Process for Auxetic Structures under Impact

Shepherd

Winwood

Venkatraman

et al. 2020

Physica Status Solidi (b)

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Poisson's ratio (ν) is the negative ratio of the lateral-to-axial strain of a material under compression or tension and ranges between À1 and þ0.5 for 3D isotropic materials, according to elasticity theory, [1] and À1 and þ1 for 2D isotropic materials. [2] Auxetic materials (and structures) have a negative Poisson's ratio (NPR) as they expand laterally when stretched and contract laterally when compressed. [3] Auxetics can have enhanced properties including increased resistance to indentation and increased energy absorption under compression. [4,5] They also exhibit synclastic curvature, [3,6] which could improve the conformability of clothing to the body. Such properties make auxetics ideal candidates for enhancing personal protective equipment (PPE) in sport, [7] such as those used in rugby, [8] American football, [9] or snow sports. [10] Head injuries, for example, still frequently occur in sport despite developments in helmet technology and increased user uptake. [11,12] Shear thickening materials are often used in sporting PPE products, such as snowboard back protectors, but their ability to limit impact forces can change with temperature. [13] Approximately 4.5 million people are treated in EU hospitals for sports-related injuries annually, [14] at a cost of €2.4 billion (%£2 billion), [15] which could be reduced with more effective protection and better regulation. Better fitting, more comfortable, and higher-performing auxetic PPE has the potential to increase participation in sport and improve general well-being, both physically and mentally. [16] In addition, a more active population could reduce healthcare costs, particularly as National Health Service providers spent %£900 million on addressing health issues related to physical inactivity in the UK in 2009/2010. [17] There are also social health benefits of practicing a sport with others. [18] Bailly et al. found that snow-sport participants with an injury that was not to the head were less likely to be wearing a helmet than those without an injury, [19] challenging the concerns of Wilson that sporting participants who wear PPE take more risks. [20] Although auxetic systems can be found in nature, [21] research into these materials has typically focused on manmade products like open-cell foam, which was first manufactured by Lakes using thermomechanical techniques that combined compression and heating. [3] Auxetic foam fabrication has also been investigated by Chan and Evans. [4,22] Scarpa et al. were the first to report the dynamic response of auxetic open-cell foam, highlighting its potential in crashworthiness applications. [23] More recently, this potential was demonstrated further; open-cell auxetic foam reduced the peak acceleration of drop tower impacts (energies up to 5.6 J) by two to three times, compared with its conventional

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“…impact [54,172,195] are crucial to design protective equipment, such as jounce bumpers for automotive suspension [196] and nonpneumatic tire. [197] In the field of ergonomics, AMMs are also used to design cushions to improve the comfort of seats.…”

Section: Other Applicationsmentioning

confidence: 99%

Progress in Auxetic Mechanical Metamaterials: Structures, Characteristics, Manufacturing Methods, and Applications

et al. 2020

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Auxetic mechanical metamaterials (AMMs), as an exciting paradigm of metamaterials, have attracted increasing attention due to their interesting mechanical properties (e.g. negative Poisson's ratio), as well as the emergence of advanced manufacturing technology (e.g. 3D printing). Although various reviews on AMMs, their structures, properties, and applications, have existed, it still lacks a comprehensive review in terms of manufacturing methods. Herein, the latest progress in AMMs is extensively reviewed, including AMMs' structures, characteristics, manufacturing methods, and applications. In addition, the current challenges and future works of AMMs are concluded and discussed. This Review aims to serve as a collection of knowledge that supplies more comprehensive understanding and inspiration to support further developments of AMMs from the perspective of design and manufacturing.

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A negative Poisson's ratio suspension jounce bumper

Cited by 86 publications

References 23 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

Validation of a Finite Element Modeling Process for Auxetic Structures under Impact

Progress in Auxetic Mechanical Metamaterials: Structures, Characteristics, Manufacturing Methods, and Applications

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