A 3D-printed stretchable structural supercapacitor with active stretchability/flexibility and remarkable volumetric capacitance

2020 ◽  
Vol 8 (27) ◽  
pp. 13646-13658 ◽  
Author(s):  
Peng Chang ◽  
Hui Mei ◽  
Yuanfu Tan ◽  
Yu Zhao ◽  
Weizhao Huang ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Negative Poisson's Ratio ◽  
3D Printed ◽  
Volumetric Capacitance

3D-printed stretchable negative Poisson's ratio structural CoNi2S4/NiCo-LDHs-based supercapacitor with active stretchability/flexibility and remarkable volumetric capacitance are built.

scholarly journals The 3D-Printed Honeycomb Metamaterials Tubes with Tunable Negative Poisson’s Ratio for High-Performance Static and Dynamic Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1353
Author(s):  
Chunxia Guo ◽  
Dong Zhao ◽  
Zhanli Liu ◽  
Qian Ding ◽  
Haoqiang Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Poisson’S Ratio ◽  
Dynamic Compression ◽  
Equal Mass ◽  
Peak Force ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Negative Poisson's Ratio ◽  
3D Printed

The synthesized understanding of the mechanical properties of negative Poisson’s ratio (NPR) convex–concave honeycomb tubes (CCHTs) under quasi-static and dynamic compression loads is of great significance for their multifunctional applications in mechanical, aerospace, aircraft, and biomedical fields. In this paper, the quasi-static and dynamic compression tests of three kinds of 3D-printed NPR convex–concave honeycomb tubes are carried out. The sinusoidal honeycomb wall with equal mass is used to replace the cell wall structure of the conventional square honeycomb tube (CSHT). The influence of geometric morphology on the elastic modulus, peak force, energy absorption, and damage mode of the tube was discussed. The experimental results show that the NPR, peak force, failure mode, and energy absorption of CCHTs can be adjusted by changing the geometric topology of the sinusoidal element. Through the reasonable design of NPR, compared with the equal mass CSHTs, CCHTs could have the comprehensive advantages of relatively high stiffness and strength, enhanced energy absorption, and damage resistance. The results of this paper are expected to be meaningful for the optimization design of tubular structures widely used in mechanical, aerospace, vehicle, biomedical engineering, etc.

Behavior of Soft 3D-Printed Auxetic Structures Under Various Loading Conditions

2018 ◽  
Author(s):  
Mahmoud K. Ardebili ◽  
Kerim Tuna Ikikardaslar ◽  
Erik Chauca ◽  
Feridun Delale
Keyword(s):  
Poisson’S Ratio ◽  
Tensile Load ◽  
Geometric Parameters ◽  
Poisson's Ratio ◽  
Impact Loads ◽  
Negative Poisson’S Ratio ◽  
Auxetic Structures ◽  
Circular Holes ◽  
Negative Poisson's Ratio ◽  
3D Printed

Auxetic structures exhibiting non-linear deformation are a prevalent research topic in the material sciences due to their negative Poisson’s ratio. The auxetic behavior is most efficiently accomplished through buckling or hinging of 3d printed structures created with soft or flexible materials. These structures have been hypothesized to have some unique characteristics and may provide advantages over conventional engineering materials in certain applications. The objective of present study is to gain a better understanding of behavior of auxetic structures subjected to tensile, compressive and impact loads and assess geometric parameters affecting these structures in applications such as impact shielding or biomedicine. Analytical and experimental methods were employed to investigate two different types of auxetic structures which were 3d-printed with TPU (thermoplastic polyurethane). The first was based on symmetric re-entrant angles cells patterned to form sheet-like structure. Rotation of members in opposite directions in a cell induces negative Poisson’s ratio when the structure is subjected to tensile loading. The second structure was based on rectangular lattice of circular holes. This structure exhibited auxeticity due to formation of pattern of alternating mutually orthogonal ellipses when subjected to compressive and impact loads. Parameters of interest in this study included hardness of the plastic used in printing the structures, the fill pattern of 3d-printed solid parts, porosity of cylinders in the lattice structure, angles and thickness of members in the re-entrant structure. Preliminary results indicated that per unit weight of material, the re-entrant structure requires less tensile load to strain than a solid structure. This is advantageous in applications where expansion in lateral direction is required. The lattice of circular holes structure exhibited similar trend in impact and compressive loading. The results indicate that geometric parameters influence auxeticity of the structure a great deal. When the porosity of the lattice is too small, positive Poisson’s ratio is observed. The length to height ratio of the re-entrant cell has similar effect on the structure’s Poisson’s ratio. The main advantage gained by employing such structures is their overall ability to resist buckling and withstand impact load without cracking. This study will help to develop 3D-printing techniques in manufacturing better performing structures under similar conditions.

Free vibration and sound insulation of functionally graded honeycomb sandwich plates

2021 ◽  
pp. 109963622110204
Author(s):  
Fenglian Li ◽  
Wenhao Yuan ◽  
Chuanzeng Zhang
Keyword(s):  
Free Vibration ◽  
Poisson’S Ratio ◽  
Functionally Graded ◽  
Poisson's Ratio ◽  
Dynamic Equations ◽  
Sound Insulation ◽  
Sandwich Plates ◽  
Negative Poisson’S Ratio ◽  
Honeycomb Sandwich ◽  
Negative Poisson's Ratio

Based on the hyperbolic tangent shear deformation theory, free vibration and sound insulation of two different types of functionally graded (FG) honeycomb sandwich plates with negative Poisson’s ratio are studied in this paper. Using Hamilton’s principle, the vibration and vibro-acoustic coupling dynamic equations for FG honeycomb sandwich plates with simply supported edges are established. By applying the Navier’s method and fluid–solid interface conditions, the derived governing dynamic equations are solved. The natural frequencies and the sound insulation of FG honeycomb sandwich plates obtained in this work are compared with the numerical results by the finite element simulation. It is proven that the theoretical models for the free vibration and the sound insulation are accurate and efficient. Moreover, FG sandwich plates with different honeycomb cores are investigated and compared. The corresponding results show that the FG honeycomb core with negative Poisson’s ratio can yield much lower frequencies. Then, the influences of various geometrical and material parameters on the vibration and sound insulation performance are systematically analyzed.

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