Article
Mechanics
Sree Kalyan Patiballa, Girish Krishnan
Summary: This paper presents a two-phase design methodology for the conceptual synthesis of three-dimensional tunable mechanical metamaterials. The first phase involves obtaining a kinematically feasible conceptual topology using a building block-based design approach, while in the second phase, the conceptual topology is refined using shape/size optimization to meet specific elastic properties and manufacturing requirements. The efficacy of the framework is demonstrated through the design of microstructures with negative Poisson's ratios and the ability to achieve isotropic microstructures from a qualitative understanding of the conceptual designs.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2022)
Article
Materials Science, Multidisciplinary
Yi He, Dong Li, Na Zhou, Lin Gan, Jin Huang
Summary: A strategy of transforming cell shape from convex to concave through viscoelastic compression was proposed, aiming to reverse the Poisson's ratio of biomass foam to negative and enhance its compression and shockproof properties. The preparation of poly(butylene succinate) foam with negative Poisson's ratio (NPR) showed significant improvements in compressive modulus, storage modulus, and loss modulus, indicating the universal potential of viscoelastic compression for reinforcing biomass foam materials.
ACS APPLIED POLYMER MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Dianwei Gao, Chunwei Zhang, Jianhua Zhang
Summary: This study investigates the Poisson's ratio of 2D and 3D nested helical structures through theoretical analysis and numerical simulations. The results show that impact velocity strongly influences the energy absorption and deformation behavior of the proposed 3D helical structure, increasing the beam radius reduces energy absorption capability, but the yield strength of nodes has minimal effect on energy absorption capability, and impact direction affects the energy absorption performance depending on the crushing strain. These findings can be utilized to optimize the design of the proposed novel 3D helical honeycombs for various applications, such as impact energy absorbers and vibration-resistant dampers.
APPLIED SCIENCES-BASEL
(2023)
Article
Materials Science, Multidisciplinary
Y. Yao, Y. Ni, L. H. He
Summary: The study explores the origin of negative Poisson's ratio in rutile-type oxides and fluorides through density functional theory (DFT) simulation, highlighting the dominant role of nearest-neighbor central force interactions. A new three-dimensional mechanical metamaterial is designed by mimicking the bond structure via elastic beams. The analytical expressions for the effective Poisson's ratio and compressibility are derived and validated by finite element computations, indicating the material can exhibit negative Poisson's ratio and negative linear, area, or volume compressibility simultaneously.
MATERIALS & DESIGN
(2021)
Article
Materials Science, Multidisciplinary
V Harinarayana, Y. C. Shin
Summary: In this study, a comprehensive design and fabrication of a three-dimensional axisymmetric auxetic structure that exhibits uniform and axisymmetric transverse deformation under longitudinal compression loading is proposed. The design of the metamaterial is generated by revolving a two-dimensional parabolic curve along the axis of rotation and subsequently perforating the structure periodically with elliptical voids. The significance of the perforations is elucidated by comparing the metamaterial structure to a plain structure.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Review
Materials Science, Multidisciplinary
James N. Grima-Cornish, Daphne Attard, Joseph N. Grima, Kenneth E. Evans
Summary: The article explores how ancient symmetrical esthetic artifacts have been transformed into functional auxetics through mechanisms in the field of mechanical metamaterials and architected materials. It focuses on the important role and various implementations of rotating rigid units at different scales of structure.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Physics, Applied
Wen-Ting Gao, Chenwen Yang, Yu-Tao Tan, Jie Ren
Summary: This study demonstrates a method to reverse the topological non-reciprocity by mechanically stretching and compressing an acoustic metamaterial, switching the Poisson's ratio from positive to negative. The design of a topological wave splitter based on adjusting the device's Poisson's ratio is also proposed.
APPLIED PHYSICS LETTERS
(2022)
Review
Materials Science, Multidisciplinary
Ebba Montgomery-Liljeroth, Silvia Schievano, Gaetano Burriesci
Summary: The field of auxetics, which focuses on materials or structures with a negative Poisson's ratio, has gained attention due to their advantageous properties including high indentation and shear resistance. Significant progress has been made in understanding the factors contributing to auxetic behavior, resulting in a wide variety of designed structures. This review provides an overview of identified and designed auxetic structures, discussing their mechanical behavior, structural properties, limitations, and potential applications, with a focus on important works and complementary research.
APPLIED MATERIALS TODAY
(2023)
Article
Engineering, Mechanical
Luke Mizzi, Andrea Sorrentino, Andrea Spaggiari, Davide Castagnetti
Summary: This study used Finite Element Analysis to investigate the impact of ligaments on rotating unit systems, finding that ligaments have a profound influence on most mechanical properties and off-axis loading behavior, leading to increased anisotropy and reduced stiffness levels in systems with ligaments.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE
(2021)
Article
Engineering, Marine
Zhiping Wang, Gang Chen, Xiaofei Cao, Wei Chen, Chun Bao Li, Xiaobin Li, Josko Parunov
Summary: This study investigates the effect of nodal configuration on the mechanical properties of hexachiral honeycombs. It reveals that nodal reinforcement improves the negative Poisson's ratio properties of the honeycomb, and nodal filling plays a significant role in enhancing the specific absorption energy.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Review
Instruments & Instrumentation
Matthew Wallbanks, Muhammad Farhan Khan, Mahdi Bodaghi, Andrew Triantaphyllou, Ahmad Serjouei
Summary: Auxetic metamaterials exhibit the unexpected behavior of negative Poisson's ratio, expanding transversely when stretched longitudinally, which has applications in energy absorption, sensors, smart filters, vibration isolation, and medical fields. The potential of these structures can be further explored through additive manufacturing. There is currently a lack of guidance on the design of these structures, and this paper provides insights into the state-of-the-art and design approaches.
SMART MATERIALS AND STRUCTURES
(2022)
Article
Chemistry, Multidisciplinary
Zaishan Lin, Jiaqi Dong, Xin Wang, Qitao Huang, Xi Shen, Minglong Yang, Xianxian Sun, Ye Yuan, Shasha Wang, Yuanhao Ning, Shuang Yang, Weilong Yin, Menglin Li, Yiwei Sun, Qiangqiang Zhang, Yibin Li
Summary: When flexible graphene nanosheets are assembled into a 3D porous architecture, anomalous mechanical properties can be induced. In this study, a 3D hierarchical graphene metamaterial (GTM) with twin-structured morphologies is assembled by manipulating the temperature gradient for ice growth. GTM demonstrates improved mechanical properties along different directions.
ADVANCED MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Yisong Bai, Chuanbao Liu, Yang Li, Jinxu Li, Lijie Qiao, Ji Zhou, Yang Bai
Summary: Mechanical metamaterials provide a feasible approach for achieving customized mechanical and thermal deformation. These metamaterials, constructed with curved bimaterial strips, can exhibit programmable and anisotropic thermal deformation through coding the unit cells. The fabricated metamaterials are verified experimentally and show unusual deformation modes.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Oliver Skarsetz, Viacheslav Slesarenko, Andreas Walther
Summary: This study introduces shape morphing of a hydrogel metamaterial by integrating responsive actuating elements to reconfigure the mesoscale unit cell geometry, achieving programmable auxeticity. The ability to programmably change the unit cell angle from 68 degrees to 107 degrees results in negative, zero, or positive Poisson's ratio under tensile strain. Finite element simulation confirms the predicted geometrical reconfiguration and programmable auxeticity.
Article
Engineering, Civil
Yang Pan, Xue Gang Zhang, Dong Han, Wei Li, Lin Fang Xu, Yi Zhang, Wei Jiang, Sai Bao, Xing Chi Teng, Tao Lai, Xin Ren
Summary: This study investigated the out-of-plane mechanical properties and deformation patterns of a recently proposed auxetic structure, the chiral lattice with circular nodes (NCL), under quasi-static uniaxial compression. The results showed that the NCL structure had superior energy absorption capacity in the out-of-plane direction compared to two benchmarks, the truss lattice and traditional chiral lattice (TCL). Parametric studies were also conducted to investigate the effects of geometric parameters and volume fraction on the structural deformation patterns and mechanical properties.
THIN-WALLED STRUCTURES
(2023)
Review
Materials Science, Multidisciplinary
James N. Grima-Cornish, Daphne Attard, Joseph N. Grima, Kenneth E. Evans
Summary: The article explores how ancient symmetrical esthetic artifacts have been transformed into functional auxetics through mechanisms in the field of mechanical metamaterials and architected materials. It focuses on the important role and various implementations of rotating rigid units at different scales of structure.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Mechanics
Russell Galea, Krzysztof K. Dudek, Pierre-Sandre Farrugia, Louis Zammit Mangion, Joseph N. Grima, Ruben Gatt
Summary: This study demonstrates the potential of a novel accordion-like magneto-mechanical metamaterial to change dimensions controllably under an external magnetic field, and return to its initial shape. It can also serve as a building block for larger 3D systems, transitioning its mechanical properties from positive to negative Poisson's ratio based on the external magnetic field.
COMPOSITE STRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Pierre-Sandre Farrugia, Ruben Gatt, Luke Mizzi, Joseph N. Grima
Summary: The deformation behavior of intersecting ligaments forming variants of the square and rectangular grids under mechanical compression was investigated. It was shown that these systems can exhibit a negative incremental Poisson's ratio at relatively large axial compressive strains. The extent of auxeticity depends on the relative offset of successive ligaments, the relative lengths of the ligaments as well as on their thickness. Two distinct modes of deformation were observed, one resembling that of the reentrant hexagonal honeycomb and the other that of the meta-tetrachiral system.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2023)
Article
Chemistry, Physical
Jakub W. Narojczyk, Mikolaj Bilski, Joseph N. Grima, Przemyslaw Kedziora, Dmitrij Morozow, Miroslaw Rucki, Krzysztof W. Wojciechowski
Summary: Negative Poisson's ratio materials challenge our traditional understanding of elastic properties and offer a wide range of potential applications. Modifying the structure of existing materials allows us to control elastic properties and anisotropy in cubic systems.
Article
Mechanics
Luke Mizzi, Andrea Spaggiari
Summary: This study investigates the impact of introducing geometric chiral characteristics on the mechanical properties of Euclidean polygonal tessellations with octahedral or dodecahedral elements. The research discovers three novel auxetic metamaterials with potentially large negative Poisson's ratios and high in-plane isotropy. It further demonstrates the control of auxeticity through tuning the geometric parameters. This work highlights the potential of Euclidean polygonal tessellations in designing innovative auxetic metamaterials and provides insights into the deformation mechanisms and geometric conditions that lead to this anomalous property.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Andrea Sorrentino, Davide Castagnetti, Luke Mizzi, Andrea Spaggiari
Summary: This work investigates the mechanical response of bio-inspired titanium mechanical metamaterials with negative Poisson's ratio evolved from rotating squares unit. The proposed solution consists of a combined auxetic rotating/chiral architecture with enhanced mechanical and topological properties which exhibits a 3% of global elastic strain of the structure and a Poisson's ratio equal to -0.94. The work confirms the great potential of biologically inspired auxetic metamaterials, which can be designed to obtain tailored mechanical properties while improving the elastic strains capabilities of the system.
MECHANICS OF MATERIALS
(2022)
Article
Instruments & Instrumentation
Luke Mizzi, Seyedeh Farzaneh Hoseini, Marco Formighieri, Andrea Spaggiari
Summary: Shape memory alloys (SMA) are used in a novel SMA-metamaterial actuator to achieve a reversible, global elongation in multiple directions. The actuator consists of an SMA component, a bias component, and a metamaterial geometry that amplify and re-direct the unidirectional SMA actuation. A prototype actuator was tested in different configurations to demonstrate its functionality and reusability. A theoretical model was developed to predict the actuation stroke based on material properties and geometry, and was validated.
SMART MATERIALS AND STRUCTURES
(2023)
Article
Mechanics
K. K. Dudek, L. Mizzi, J. A. Iglesias Martinez, A. Spaggiari, G. Ulliac, R. Gatt, J. N. Grima, V. Laude, M. Kadic
Summary: The ability to control Poisson's ratio of functional materials is essential for the development of efficient structures in various fields. This study proposes novel microscopic 2D and 3D functionally-graded mechanical metamaterials that can exhibit a wide range of Poisson's ratio depending on their composition. The research also explores the dynamic properties of these structures, specifically how the variation in composition affects wave propagation velocity. This has significant implications for applications involving wave attenuation or sensors.
COMPOSITE STRUCTURES
(2023)
Article
Biotechnology & Applied Microbiology
Tonio P. Agius, Dario Cerasola, Michael Gauci, Anabel Sciriha, Darren Sillato, Cynthia Formosa, Alfred Gatt, John Xerri de Caro, Robert Needham, Nachiappan Chockalingam, Joseph N. Grima
Summary: This study analyzes the specific kinematics of fixed-seat rowing and compares it with sliding-seat rowing. The results show that fixed-seat rowing involves more forward and backward movement of the thorax, but less spinal movement compared to sliding-seat rowing. This biomechanical explanation helps to understand why fixed-seat rowers do not have an increased risk of back injuries compared to sliding-seat rowers.
BIOENGINEERING-BASEL
(2023)
Article
Engineering, Multidisciplinary
Daphne Attard, Roberto Caruana-Gauci, Dario Cerasola, James N. Grima-Cornish, Daniel S. Bezzina, Giovanni Ficarra, Joseph N. Grima
Summary: Finite element simulations were carried out to examine the effect of shearing on finite-sized auxetic and non-auxetic samples. It was found that auxetics exhibited distinct characteristics compared to non-auxetic materials when subjected to shear testing, including extensive lateral expansion and the formation of significant concave creases on exposed lateral faces. The presence of these creases became more pronounced under combined shear and compressive loads, highlighting the need to consider their influence when evaluating the suitability of auxetics for practical applications involving shear loading.
ENGINEERING RESEARCH EXPRESS
(2023)
Article
Medicine, General & Internal
Joseph N. Grima, Michelle Vella Wood, Nadia Portelli, James N. Grima-Cornish, Daphne Attard, Alfred Gatt, Cynthia Formosa, Dario Cerasola
Summary: This study investigated the prevalence of dermatological issues (calluses and blisters) on rowers' hands, as well as their perceptions and pain tolerance. The results showed that most rowers considered calluses to be non-painful, while blisters were perceived as more painful. Blisters and calluses were mainly located on the lower parts of the fingers and the upper inner palms.
MEDICINA-LITHUANIA
(2022)
