Hybrid auxetic materials implemented in crates & non-pneumatic wheels for shock absorption

2021 ◽  
Author(s):  
Ankan Narayan Biswas ◽  
Nunna Mahesh ◽  
Shanmukha Ram Peri ◽  
Bharath R Krishnan ◽  
P.S. Rama Sreekanth
Keyword(s):  
Shock Absorption ◽  
Auxetic Materials

Application of Auxetic Polymeric Structures for Body Protection

2016 ◽  
Author(s):  
Chulho Yang ◽  
Hitesh D. Vora ◽  
Young B. Chang
Keyword(s):  
Structural Characteristics ◽  
Polymeric Materials ◽  
The Body ◽  
Material Structure ◽  
Light Weight ◽  
Body Parts ◽  
Shock Absorption ◽  
Element Analysis ◽  
Auxetic Materials ◽  
Polymeric Structures

Negative Poisson’s ratio (NPR) materials, also known as auxetic materials, have many promising application areas. In recent years, various auxetic material structures have been designed and fabricated for diverse applications that utilized normal materials which follow Hooke’s law but still show the properties of negative Poisson’s ratios. In light of this, efforts are made to apply auxetic material structures to body protection pads that are comfortable to wear and effective in protecting body parts by reducing impact force and preventing injuries in high-risk individuals such as elderly people, industry workers, law enforcement and military personnel, and sport players. For those people, blunt impacts such as falls, bullets, and blast wave may reduce quality of life, increase the possibility of early death and generate an extremely high medical costs. Therefore, it is important to develop new body protectors that best combine each individual’s requirements of wearing comfort (flexible, light weight), ease of fitting (customized), ensured protection, and cost-effectiveness. The developed protection pad would be made from multilayer materials with an adaptive structure to achieve a unique multifunctional properties such as high hardness, impact toughness, light weight, excellent shock absorption, self-assembly suitable for the needs. Particularly, an integrated computational (finite element analysis) approach is used to investigate the effect of three material structures (honeycomb or flexin structure, re-entrant hexagonal cells or reflexin structure, and arrowhead structure) in combination with three polymeric materials (Polylactic acid (PLA) and two thermoplastic polyurethane (TPU) materials). Efforts are made to relate the individual and/or combined effect of auxetic structure and materials to the overall stiffness and shock-absorption performance of the body protection pads. Initially, parametric 3D CAD models of auxetic polymeric structures are developed. Later, key structural characteristics of protectors are evaluated through static analyses of FEA models. Impact/shock analyses are conducted to validate the results obtained from the static analyses. The mechanism for ideal input force distribution or shunting is suggested for designing protectors using various shapes, thicknesses, and materials of auxetic materials to reduce the risk of injury. The results show that the auxetic material can be considered as an effective material structure for body protection pads.

Evaluation of Auxetic Polymeric Structures for Use in Protective Pads

2016 ◽  
Author(s):  
Chulho Yang ◽  
Hitesh D. Vora ◽  
Young Bae Chang
Keyword(s):  
Poisson’S Ratio ◽  
Polymeric Materials ◽  
Poisson's Ratio ◽  
Light Weight ◽  
Negative Poisson’S Ratio ◽  
Shock Absorption ◽  
Fused Deposition ◽  
Auxetic Materials ◽  
Negative Poisson's Ratio ◽  
Polymeric Structures

Auxetic materials, known as materials with negative Poisson’s ratio (NPR), have many promising application areas. However, there are only few natural and man-made materials such as certain living bone tissues, certain rocks and minerals, polymeric honeycombs, microporous polytetrafluoroethylene (PTFE), foams, and carbon-fiber-reinforced epoxy composite laminate panels that possess this property. In recent years, various auxetic material structures have been designed and fabricated for diverse applications that utilized normal materials which follow Hooke’s law but still show the NPR properties. One of the applications is body protection pads that are comfortable to wear and effective in protecting body parts by reducing impact force and preventing injuries in high-risk individuals such as elderly people, industry workers, law enforcement and military personnel, and sports players. It is important to develop new body protectors that best combine each individual’s requirements for wearing comfort (flexible, light-weight), ease of fitting (customized), ensured protection, and cost-effectiveness. The protection pad would be made from multilayer materials and adaptive structures to achieve unique multifunctional properties such as high hardness, impact toughness, light weight, and excellent shock absorption suitable for the needs. This paper reports an integrated theoretical, computational (finite element analysis), and experimental investigation conducted for typical auxetic polymeric materials that exhibit negative Poisson’s ratio (NPR) effect. Parametric 3D CAD models of auxetic polymeric structures such as re-entrant hexagonal cells and arrowhead were developed. Then, key structural characteristics of protectors were evaluated through static analyses of FEA models. In addition, impact/shock analyses were conducted through dynamic analyses of FEA models to validate the results obtained from the static analyses. Particularly, an advanced additive manufacturing (3D printing) technique was used to build prototypes of the auxetic polymeric structures. Specifically, three different materials typically used for FDM (Fused Deposition Modeling) technology such as Polylactic acid (PLA) and thermoplastic polyurethane (TPU) material (NinjaFlex® and SemiFlex®) were used for different stiffness and shock-absorption performances. The 3D printed prototypes were then tested and the results were compared with the computational prediction. The results showed that the auxetic material can be effective for body protection pads. Each structure and material had unique structural properties such as stiffness, Poisson’s ratio, and efficiency in shock absorption. Particularly, auxtetic structures showed better shock absorption performance than non-auxetic ones. The mechanism for ideal input force distribution or shunting could be suggested for designing protectors using various shapes, thicknesses, and materials of auxetic materials to reduce the risk of injury.

scholarly journals Application of Glass Fiber and Carbon Fiber-Reinforced Thermoplastics in Face Guards

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 18
Author(s):  
Takahiro Wada ◽  
Hiroshi Churei ◽  
Mako Yokose ◽  
Naohiko Iwasaki ◽  
Hidekazu Takahashi ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Glass Fiber ◽  
Impact Testing ◽  
Fiber Reinforced ◽  
Shock Absorption ◽  
Glass Fiber Reinforced ◽  
Field Of Vision ◽  
Commercial Glass ◽  
Carbon Fiber Reinforced ◽  
Reinforced Thermoplastics

Face guards (FGs) are protectors that allow for the rapid and safe return of athletes who are to play after sustaining traumatic facial injuries and orbital fractures. Current FGs require significant thickness to achieve sufficient shock absorption abilities. However, their weight and thickness render the FGs uncomfortable and reduce the field of vision of the athlete, thus hindering their performance. Therefore, thin and lightweight FGs are required. We fabricated FGs using commercial glass fiber-reinforced thermoplastic (GFRTP) and carbon fiber-reinforced thermoplastic (CFRTP) resins to achieve these requirements and investigated their shock absorption abilities through impact testing. The results showed that an FG composed of CFRTP is thinner and lighter than a conventional FG and has sufficient shock absorption ability. The fabrication method of an FG comprising CFRTP is similar to the conventional method. FGs composed of commercial FRTPs exhibit adequate shock absorption abilities and are thinner and lower in weight as compared to conventional FGs.

scholarly journals Giant negative Poisson’s ratio in two-dimensional V-shaped materials

2021 ◽  
Author(s):  
Xikui Ma ◽  
Jian Liu ◽  
Yingcai Fan ◽  
Weifeng Li ◽  
Jifan Hu ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Two Dimensional ◽  
Auxetic Materials ◽  
Negative Poisson's Ratio ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Two-dimensional (2D) auxetic materials with exceptional negative Poisson’s ratios (NPR) are drawing increasing interest due to the potentials in medicine, fasteners, tougher composites and many other applications. Improving the auxetic...

The Comparative Analysis of Cushion or Shock Absorption Characteristic of Commonly-Used Cushion Packaging Materials

2012 ◽  
Vol 490-495 ◽  
pp. 3902-3906 ◽  
Author(s):  
Zhen Jie Du ◽  
Wan Yu Gao ◽  
Hai Hong Kang ◽  
Sheng Jun Liu ◽  
Ming Xi Hu ◽  
...  
Keyword(s):  
Dynamic Compression ◽  
Static Stress ◽  
Final Conclusion ◽  
Absorption Characteristic ◽  
Packaging Materials ◽  
Shock Absorption ◽  
Static Test ◽  
Reference Information ◽  
Stress Curve ◽  
Packaging Structure

The purpose and method of this paper is to comparatively analyze several commonly-used cushion packaging materials, obtain their shock absorption characteristic curves, and by doing such, provide reference information for cushion packaging design and research. With the static test, dynamic compression test and vibration transfer test carried out, the cushion coefficient ~ static stress curve, maximal acceleration ~ static stress curve and vibration transfer rate ~ frequency curve are gained. A final conclusion is educed that in practical design routine, rational choice of cushion packaging materials, scientific design of packaging structure and validation of anti-vibration capability are relative to those three curves.

Auxetic Materials and Related Systems

2012 ◽  
Vol 249 (7) ◽  
pp. 1313-1314 ◽  
Author(s):  
Ruben Gatt ◽  
Joseph N. Grima ◽  
Jakub W. Narojczyk ◽  
Krzysztof W. Wojciechowski
Keyword(s):  
Auxetic Materials
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