Auxetics (negative Poisson's ratio) and materials with negative linear compressibility (NLC) exhibit the anomalous mechanical properties of getting wider rather than thinner when stretched and expanding in at least one direction under hydrostatic pressure, respectively. A novel mechanism-termed the 'triangular elongation mechanism'-leading to such anomalous behavior is presented and discussed through an analytical model. Amongst other things, it is shown that this novel mechanism, when combined with the well-known 'rotating squares' model, can generate giant negative Poisson's ratios when the system is stretched.
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http://dx.doi.org/10.3390/ma13010079 | DOI Listing |
Phys Chem Chem Phys
January 2025
Department of Physics, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, People's Republic of China.
Two-dimensional (2D) carbon allotropes, together with their binary and ternary counterparts, have attracted substantial research interest due to their peculiar geometries and properties. Among them, grapheneplus, a derivative of penta-graphene, has been proposed to exhibit unusual mechanical and electronic behaviour. In this work, we perform a comprehensive first-principles study on its isoelectronic and isostructural analogue, a grapheneplus-like BCN (gp-BCN) monolayer.
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January 2025
Heilongjiang Ground Pressure and Gas Control in Deep Mining Key Laboratory, Heilongjiang University of Science and Technology, Harbin, 15002, China.
When underground tunnels in coal mines traverse geological structurally abnormal zones (faults, collapse columns, fractured zones, etc.), excavation-induced unloading leads to instability and failure of the engineering rock mass. Rock masses in fractured zones are in elastic, plastic, and post-peak stress states, and the process of excavation through these zones essentially involves unloading under full stress paths.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Department of Industrial Engineering, University of Trento, 38123 Trento, Italy.
The metastable β-Ti21S alloy exhibits a lower elastic modulus than Ti-6Al-4V ELI while maintaining high mechanical strength and ductility. To address stress shielding, this study explores the integration of lattice structures within prosthetics, which is made possible through additive manufacturing. Continuous adhesion between the implant and bone is essential; therefore, auxetic bow-tie structures with a negative Poisson's ratio are proposed for regions under tensile stress, while Triply Periodic Minimal Surface (TPMS) structures with a positive Poisson's ratio are recommended for areas under compressive stress.
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December 2024
Department of Mechanical Engineering, Kermanshah University of Technology, Kermanshah 6715685420, Iran.
The significance of this paper is an investigation into the design, development, and optimization of a new polymeric hybrid auxetic structure by additive manufacturing (AM). This work will introduce an innovative class of polymeric hybrid auxetic structure by the integration of an arrow-head unit cell into a missing rib unit cell, which will be fabricated using fused filament fabrication (FFF) technique, that is, one subset of AM. The auxetic performance of the structure is validated through the measurement of its negative Poisson's ratio, confirming its potential for enhanced energy absorption.
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January 2025
Department of Geotechnical Engineering, School of Civil Engineering, Tongji University, Shanghai, 200000, China.
This study investigates the vulnerability of expansive soil slopes to destabilization and damage, particularly under intense rainfall, due to their heightened sensitivity to moisture. Focusing on a project in Yunnan Province, numerical simulation software is employed to address slope stability challenges. Meanwhile, the soil mechanical parameters of this study were acquired through experimentation.
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