Article
Instruments & Instrumentation
O. Duncan, G. Leslie, S. Moyle, D. Sawtell, T. Allen
Summary: Auxetic closed cell foam can be manufactured using pressure-vessel methods, with a noticeable settling period observed post processing. Placing the foam in a vacuum can reduce the settling period to within 24 hours.
SMART MATERIALS AND STRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Antonio Baldi, Michele Brun, Giorgio Carta
Summary: The proposed design of a novel three-dimensional porous continuous solid with negative Poisson's ratio exhibits cubic symmetry and moderate degree of anisotropy. The directional dependence of Poisson's ratio and Young's modulus shows multidirectional auxeticity. Numerical results are validated by experimental results from Digital Image Correlation data, with potential for large-scale industrial production.
MECHANICS OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Olly Duncan, Nicolas Bailly, Tom Allen, Yvan Petit, Eric Wagnac, Andrew Alderson
Summary: This study aimed to measure the effect of strain rate on the stiffness and Poisson's ratio of auxetic and conventional foams. The results showed that the Poisson's ratio of auxetic foams halved at high strain rates, while the Young's moduli of conventional foam approximately doubled at the highest applied strain rate.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Civil
Xin Ren, Yi Zhang, Chuan Zhen Han, Dong Han, Xiang Yu Zhang, Xue Gang Zhang, Yi Min Xie
Summary: By filling rigid polyurethane foam into hollow auxetic tubes, this study successfully enhanced the energy absorption capacity. The composite foam-filled auxetic tubes demonstrated superior energy absorption compared to single foams and hollow tubes. Geometrical parameters such as wall thickness and ellipticity significantly impact the structural deformation mode and energy absorption of the FFATs.
THIN-WALLED STRUCTURES
(2022)
Article
Instruments & Instrumentation
M. Parisi, T. Allen, M. Colonna, N. Pugno, O. Duncan
Summary: Auxetic closed cell foams and highly viscoelastic foams have the potential to improve impact protection. The study found that auxetic foams outperformed unconverted foams during severe impacts, exhibiting a reduced peak force and increased indentation resistance. However, infusing the auxetic foams with shear thickening gel had minimal impact on the reduction in peak impact force, potentially due to low and non-uniform levels of infusion.
SMART MATERIALS AND STRUCTURES
(2023)
Article
Engineering, Mechanical
Qicheng Zhang, Fabrizio Scarpa, David Barton, Yunpeng Zhu, Zi-Qiang Lang, Dayi Zhang, Hua-Xin Peng
Summary: This study describes large strain quasi-static and impact tests of a new class of low-cost uniaxially thermoformed transverse isotropic auxetic foams. The results show that these foams only exhibit auxetic behavior when loaded along the transverse direction to the uniaxial thermoforming compression. The impact energy absorption performance of the foams is enhanced, and the Poisson's ratio approaches 0 at large strains.
INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
(2022)
Review
Engineering, Multidisciplinary
Wei Jiang, Xin Ren, Shi Long Wang, Xue Gang Zhang, Xing Yu Zhang, Chen Luo, Yi Min Xie, Fabrizio Scarpa, Andrew Alderson, Ken E. Evans
Summary: Auxetic foams exhibit unique mechanical properties and multiphysics characteristics, making them potential candidates for applications in biomedicine, aerospace, and smart sensing. However, challenges such as complex fabrication and lacking stability hinder their practical applications, requiring further research and development to overcome these barriers.
COMPOSITES PART B-ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Kazi Zahir Uddin, Nicholas Pagliocca, Ibnaj Anamika Anni, George Youssef, Behrad Koohbor
Summary: This study investigates the relationships between global and local strain fields in rectangular center-symmetric perforated planar structures, highlighting the role of local morphology on the macroscopic material response.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Construction & Building Technology
Mohammad Asad, Nay Win, Tatheer Zahra, David P. Thambiratnam, Tommy H. T. Chan, Yan Zhuge
Summary: This paper presents an experimental investigation on the flexural response and energy absorption of auxetic cementitious composites reinforced with polyurethane foam. The results show that the auxetic fabric overlayed composites exhibited increased energy absorption and ductility without any signs of debonding compared to the commonly used carbon fibre overlayed composites. The findings will have applications for protecting structures that are vulnerable to impacts.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Nejc Novak, Olly Duncan, Tom Allen, Andrew Alderson, Matej Vesenjak, Zoran Ren
Summary: This study analyzed the shear moduli of conventional and auxetic open-cell polymer foams, finding that the measured shear moduli of auxetic foams were generally lower, and the calculated shear moduli were lower than the measured values.
MECHANICS OF MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Yongtao Yao, Yuncheng Xu, Hao Chen, Yuying Kang, Yanju Liu, Jinsong Leng
Summary: This study presents a feasible approach to fabricate shape memory foam with auxetic property using the second curing method, achieving tunable mechanical properties and wireless actuation.
JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
(2023)
Article
Engineering, Multidisciplinary
Qicheng Zhang, Xindi Yu, Fabrizio Scarpa, David Barton, Kathryn Rankin, Zi-Qiang Lang, Dayi Zhang
Summary: This study investigates the influence of the anisotropy of the foam material on the performance of auxetic foams produced through thermoforming. The results show that the anisotropic nature of the baseline foam plays a significant role in determining the mechanical behavior of the thermoformed auxetic foams. The study also demonstrates that significant negative Poisson's ratios can be achieved in certain conditions, where the foam is thermoformed in specific directions and loaded along a particular axis.
COMPOSITES PART B-ENGINEERING
(2022)
Article
Polymer Science
Xiao Yuan Chen, Ouassim Hamdi, Denis Rodrigue
Summary: This study proposes a method to convert polyethylene foams into auxetic materials with negative Poisson's ratios, which improves their mechanical properties and energy absorption ability. By optimizing the processing conditions, low-density foams with negative Poisson's ratios were obtained. These foams can be used in various applications including sport and military protection equipment.
POLYMERS FOR ADVANCED TECHNOLOGIES
(2023)
Article
Engineering, Manufacturing
Kang Zhang, Xiyao Zhang, Qiang Gao, Meishan Chan, Shilong Zhang, Jifan Li, Wei-Hsin Liao
Summary: In this study, a novel strategy for making ultrahigh energy-dissipation auxetic foam inspired by balloon art was reported. Through finite element analysis, it was found that spherical balloons will turn to reentrant shape when compressed uniaxially in polymer matrix with large Poisson's ratio. By utilizing this knowledge, auxetic silicone foam (ASF) was successfully developed through a well-designed foaming-compression-curing process. ASF exhibits ultrahigh energy dissipation capability of about 2000 kJ/m(3), which is over 80 times higher than conventional auxetic polyurethane foams. It also possesses low water absorption, high chemical and temperature resistance, and thermal responsiveness.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2023)
Article
Materials Science, Multidisciplinary
Qicheng Zhang, Wenjiang Lu, Fabrizio Scarpa, David Barton, Kathryn Rankin, Yunpeng Zhu, Zi-Qiang Lang, Hua-Xin Peng
Summary: The study presents a simplified procedure for manufacturing auxetic PU foam using a single direction thermoforming compression process on conventional open cell foam samples. Auxetic foams exhibit transverse isotropy with specific compression ratios required to achieve auxeticity. Numerical models built from 3D scans show good agreement with experimental data and help explain deformation mechanisms of auxetic foams.
MATERIALS & DESIGN
(2021)
Article
Materials Science, Multidisciplinary
P. J. Seelan, J. M. Dulieu-Barton, F. Pierron
MECHANICS OF MATERIALS
(2020)
Article
Multidisciplinary Sciences
D. J. Bull, J. A. Smethurst, I Sinclair, F. Pierron, T. Roose, W. Powrie, A. G. Bengough
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2020)
Article
Materials Science, Characterization & Testing
Pascal Lava, Elizabeth M. C. Jones, Lukas Wittevrongel, Fabrice Pierron
Article
Materials Science, Characterization & Testing
Jared Van Blitterswyk, Lloyd Fletcher, Fabrice Pierron
Summary: The study demonstrates that even under nonuniform, through-the-thickness loading, reducing angular misalignment can decrease the impact on single-sided measurements, with a relatively minor effect on stiffness identification compared to failure stress. Three-dimensional loading has a small impact on stiffness identification (approximately 5% bias) relative to failure stress (approximately 30% bias).
Review
Materials Science, Characterization & Testing
F. Pierron, M. Grediac
Summary: This paper reviews the research on the design and optimization of heterogeneous mechanical tests for identifying material parameters from full-field measurements, termed Material Testing 2.0 (MT2.0).
Article
Nanoscience & Nanotechnology
Y. G. Tan, D. J. Bull, R. Jiang, A. Evangelou, S. Chaudhuri, S. Octaviani, F. Pierron, N. Gao, H. Toda, I Sinclair, P. A. S. Reed
Summary: The crack initiation and early propagation behavior of DS superalloy CM247LC was assessed using various imaging techniques. Three modes of secondary crack behaviors were identified, with early fatigue damage controlled by microstructure-induced cracking, mainly carbide cracking. The mechanisms of these cracking behaviors are associated with the plastic zone of the main crack tip, with carbide-induced cracking more likely to occur in the early stages of the fatigue process.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Characterization & Testing
Lloyd Fletcher, Frances Davis, Sarah Dreuilhe, Aleksander Marek, Fabrice Pierron
Summary: The assumption of quasi-static equilibrium is crucial for obtaining accurate data in split Hopkinson bar testing. Image-based inertial impact (IBII) testing has emerged as an alternative that does not require this assumption, utilizing virtual fields for material property identification. The aim of the study is to develop the IBII method for identifying elasto-plasticity in metals.
Article
Materials Science, Characterization & Testing
Lloyd Fletcher, Frances Davis, Sarah Dreuilhe, Aleksander Marek, Fabrice Pierron
Summary: This study developed a new high strain rate testing method using the IBII technique to accurately identify the transition from elasticity to plasticity in metals. Experimental validation showed that the method performed well for materials with different rate sensitivities.
Article
Materials Science, Multidisciplinary
Jin-Seong Park, Ji-Min Kim, Frederic Barlat, Ji-Ho Lim, Fabrice Pierron, Jin-Hwan Kim
Summary: The research aims to determine stress-strain curves of sheet metals at various strain rates from a single dynamic experiment. A new high-speed tensile tester was built, and full-field heterogeneous strain fields were measured using digital image correlation technique. Stress-strain curves of three advanced high strength steels at intermediate strain rates were successfully obtained from a single experiment through an inverse identification scheme with a rate dependent hardening law.
MECHANICS OF MATERIALS
(2021)
Article
Multidisciplinary Sciences
Daniel J. Bull, Joel A. Smethurst, Gerrit J. Meijer, I Sinclair, Fabrice Pierron, Tiina Roose, William Powrie, A. Glyn Bengough
Summary: Vegetation enhances soil shearing resistance through water uptake and root reinforcement. The authors measured the shear resistance and deformations of fallow, willow-rooted and gorse-rooted soils during direct shear using X-ray computed tomography and digital volume correlation for the first time, and found that root reinforcement increases shear zone thickness.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Materials Science, Characterization & Testing
Palaniappan Jaya Seelan, Fabrice Pierron, Janice M. Dulieu-Barton
Summary: In this study, a method utilizing infrared camera to measure temperature changes helps in identifying different microstructural regions of a material by analyzing the sensitivity of intrinsic dissipative heat source and temperature changes. The approach is validated by deriving thermoelastic and dissipative heat sources from 'hole-in-plate' specimen, and successfully applied to identify different microstructures resulting from a welding process.
Article
Materials Science, Characterization & Testing
John M. Considine, Nathan J. Bechle, Fabrice Pierron, David E. Krestschmann
Summary: This study designed a virtual experiment to simultaneously determine the orthotropic stiffness of earlywood and latewood in loblolly pine, and evaluated the optimal orthotropy orientation for reduced identification errors and choices for data smoothing filters and identification methodology. The results showed that certain ring spacing and latewood percentages could produce large errors, but these combinations are unlikely to occur naturally.
Article
Engineering, Mechanical
Ji -Min Kim, Jin-Seong Park, Do-Hyun Leem, Minki Kim, Fabrice Pierron, Frederic Barlat, Jin-Hwan Kim
Summary: The present study aims to characterize the hardening behavior using acceleration data without utilizing the load information for accurate evaluation at intermediate or high strain rates. Virtual measurements from a finite element model were used to check for the minimum acceleration magnitude necessary for stable identification. High-speed tensile testing equipment for steel sheet specimens was modified to increase the acceleration magnitude, and promising results were obtained by comparing the stress-strain curves obtained from the acceleration and load data.
INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
(2023)
Review
Materials Science, Characterization & Testing
Fabrice Pierron
Summary: With the development of camera-based full-field measurement techniques like digital image correlation, researchers have been exploring more complex test configurations to utilize the extensive data sets. Known as "Material Testing 2.0", this new paradigm in mechanical testing of materials is currently experiencing a significant increase in research efforts.
Article
Materials Science, Multidisciplinary
S. Parry, L. Fletcher, F. Pierron
Summary: A new Image-Based Inertial Impact (IBII) test methodology was developed to accurately determine the mechanical properties of composite materials under high strain rate conditions. Results from different sample configurations were consistent, validating the method's reliability.
JOURNAL OF DYNAMIC BEHAVIOR OF MATERIALS
(2021)
