scholarly journals Brief review of metamaterials and auxetic materials

2021 ◽  
Vol 31 ◽  
pp. 1-9
Author(s):  
Raluca Florentina NEGREA ◽  
Keyword(s):  
Energy Absorption ◽  
Mechanical Response ◽  
Deformation Pattern ◽  
Geometrical Shape ◽  
Variable Permeability ◽  
Base Materials ◽  
Mechanical Metamaterials ◽  
Auxetic Materials ◽  
Potential Applications ◽  
Absorption Performance

This paper aims to provide a comprehensive review on auxetic materials and structures, including various types of cellular auxetics, natural and artificial auxetics, metallic auxetics, multi-material and composite auxetics. A material engineered to have aproperty that is not found in naturally occurring materials is the metamaterial (meaning"beyond" from the Greek word μετά meta, and "material" from the Latin word materia) made from assemblies of multiple elements shaped from composite materials such as metals and plastics. They have exceptional properties, derive from their geometrical shape rather than directly from the behavior of the base materials, in terms of mechanical response, energy absorption and, heat transport performance.One of the most studied species of mechanical metamaterials is the auxetic materials, a type of mechanical metamaterial with a negative Poisson’s ratio (which shrink transversely under longitudinal compression and expand transversely under longitudinal tension). They consistof numerous hinge-like cells that are joined together. The cells have a re-entrant geometry, i.e. under pressure, they expand in lateral direction.Superior and unusual properties of auxetics are presented and some existing or potential applications are summarized. Accompanied by uncommon deformation pattern under compression and tension, auxetic materials and structures are endowed with many desirable material properties, such as superior shear resistance, indentation resistance, fracture resistance, synclastic behavior, variable permeability and better energy absorption performance.

Large Torsion Deformation: Centrosymmetric Reentrant Honeycomb

2022 ◽  
Vol 904 ◽  
pp. 17-25
Author(s):  
Bo Hao Xu ◽  
Shuai Wang ◽  
Kai Fa Zhou ◽  
Wen Yi Ma ◽  
Nan Sun
Keyword(s):  
Energy Absorption ◽  
Sandwich Structure ◽  
Absorption Capacity ◽  
The Other ◽  
Deformation Pattern ◽  
Deformation Capacity ◽  
Energy Absorption Capacity ◽  
Specific Energy Absorption ◽  
Absorption Performance ◽  
Torsion Deformation

There exist some problems in the crash box and anti-collision beam sandwich structure, such as monotone deformation pattern and uneconomical energy absorption performance. In order to raise the deformation capacity and energy absorption performance of sandwich structure, centrosymmetric reentrant honeycomb (CRH) and hexagonal centrosymmetric reentrant honeycomb (HCRH) are proposed based on auxetic reentrant honeycomb (ARH) in this work. Based on HCRH, four kinds of transverse combination structures and two kinds of longitudinal combination structures are obtained. The results of specific energy absorption show that the energy absorption capacity of the angular contact homodromous combination structure (ACOC) is about 3 times that of the other three transverse combination structures. Compared with longitudinal heterodromous combination structure (LHEC), the energy absorption capacity of longitudinal homodromous combination structure (LHOC) is improved by 72.7%.

Multi-objective design optimization of additively manufactured lattice structures for improved energy absorption performance

2021 ◽  
pp. 095440622199554
Author(s):  
Recep M Gorguluarslan
Keyword(s):  
Energy Absorption ◽  
Response Surfaces ◽  
Optimization Process ◽  
Truss Optimization ◽  
Size Optimization ◽  
Lattice Structures ◽  
Multi Objective ◽  
Lattice Design ◽  
Highly Nonlinear ◽  
Absorption Performance

This paper aims to improve the energy absorption performance of stiffness-optimized lattice structures by utilizing a multi-objective surrogate-based size optimization that considers the additive manufacturing (AM) constraints such as the minimum printable size. A truss optimization is first utilized at the unit cell level under static compressive loads for stiffness maximization and two optimized lattice configurations called the Face-Body Centered Cubic (FBCC) lattice and the Octet Cubic (OC) are obtained. A multi-objective size optimization process is then carried out to improve the energy absorption capabilities of those lattice designs using non-linear compression simulations with Nylon12 material to be fabricated by the Multi Jet Fusion (MJF) AM process. Thin plate spline (TPS) interpolation method is found to produce very high accuracy as the surrogate model to predict the highly nonlinear response surfaces of energy absorption objectives in the optimization. Compared to the lattice designs with uniform strut diameters, by using the optimization process, the maximum energy absorption efficiency ( EAEm) and the crush stress efficiency ( CSE) of the OC lattice design are further improved up to 33% and 37%, respectively. The FBCC lattice design is also found to have superior EAEm performance compared to the existing lattice types considered for fabricating by the MJF process in the literature.

Metamaterials with enhanced mechanical properties and tuneable Poisson’s ratio

2021 ◽  
Author(s):  
Amer Alomarah ◽  
Syed Masood ◽  
Dong Ruan
Keyword(s):  
Poisson’S Ratio ◽  
Structural Modification ◽  
Mechanical Response ◽  
Good Alternative ◽  
Poisson's Ratio ◽  
Polyamide 12 ◽  
Loading Direction ◽  
Wide Range ◽  
Potential Applications ◽  
Parametric Studies

Abstract This paper reports a structural modification of an auxetic metamaterial with a combination of representative re-entrant and chiral topologies, namely, a re-entrant chiral auxetic (RCA). The main driving force for the structural modification was to overcome the undesirable properties of the RCA metamaterial such as anisotropic mechanical response under uniaxial compression. Additively manufactured polyamide 12 specimens via Multi Jet Fusion (MJF) were quasi-statically compressed along the two in-plane directions. The experimental results confirmed that the modified structure was less sensitive to the loading direction and the deformation was more uniform. Moreover, similar energy absorptions were obtained when the modified metamaterial was crushed along the two in-plane directions. The energy absorptions were improved from 390 to 950 kJ/m³ and from 500 to 1000 kJ/m³ compared with the RCA when they were crushed along the X and Y directions, respectively. The absorbed energy per unit mass (SEA) also improved from 1.4 to 2.9 J/g and from 1.78 to 3.1 J/g compared with that of the RCA under the axial compression along the X and Y directions. Furthermore, parametric studies were performed and the effects of geometric parameters of the modified metamaterial were numerically investigated. Tuneable auxetic feature was obtained. The energy absorption and Poisson’s ratio of the modified metamaterial offer it a good alternative for a wide range of potential applications in the areas such as aerospace, automotive, and human protective equipment.

Bending Behavior of Simply-Supported Sandwich Beams Subjected to Large Deflection

2018 ◽  
Vol 777 ◽  
pp. 569-574
Author(s):  
Zhong You Xie
Keyword(s):  
Energy Absorption ◽  
Large Deflection ◽  
Absorption Efficiency ◽  
Sandwich Beams ◽  
Element Simulation ◽  
Energy Absorption Efficiency ◽  
Load Carrying ◽  
Absorption Performance ◽  
Bending Behavior ◽  
The Moment

Due to thin skins and soft core, it is apt to local indentation inducing the concurrence of geometrical and material nonlinearity in sandwich structures. In the paper, finite element simulation is used to investigate the bending behavior of lightweight sandwich beams under large deflection. A modified formulation for the moment at mid-span section of sandwich beams under large deflection is presented, and energy absorption performance is assessed based on energy absorption efficiency. In addition, it is found that no local indentation arises initially, while later that increases gradually with loading displacement increasing. The height of the mid-span section as well as load-carrying capacity decreases significantly with local indentation depth increasing.

Computational Modeling and Energy Absorption Behavior of Thin-Walled Tubes with the Kresling Origami Pattern

2021 ◽  
Vol 62 (2) ◽  
pp. 71-81
Author(s):  
Jiaqiang Li ◽  
Yao Chen ◽  
Xiaodong Feng ◽  
Jian Feng ◽  
Pooya Sareh
Keyword(s):  
Energy Absorption ◽  
Material Properties ◽  
Rotation Angle ◽  
Programming Model ◽  
Mixed Integer ◽  
Element Analysis ◽  
Cross Sectional ◽  
Thin Walled Tube ◽  
Absorption Performance ◽  
Thin Walled

Origami structures have been widely used in various engineering fields due to their desirable properties such as geometric transformability and high specific energy absorption. Based on the Kresling origami pattern, this study proposes a type of thin-walled origami tube the structural configuration of which is found by a mixed-integer linear programming model. Using finite element analysis, a reasonable configuration of a thin-walled tube with the Kresling pattern is firstly analyzed. Then, the influences of different material properties, the rotation angle of the upper and lower sections of the tube unit, and cross-sectional shapes on the energy absorption behavior of the thin-walled tubes under axial compression are evaluated. The results show that the symmetric thin-walled tube with the Kresling pattern is a reasonable choice for energy absorption purposes. Compared with thin-walled prismatic tubes, the thin-walled tube with the Kresling pattern substantially reduces the initial peak force and the average crushing force, without significantly reducing its energy absorption capacity; moreover, it enters the plastic energy dissipation stage ahead of time, giving it a superior energy absorption performance. Besides, the material properties, rotation angle, and cross-sectional shape have considerable influences on its energy absorption performance. The results provide a basis for the application of the Kresling origami pattern in the design of thin-walled energy-absorbingstructures.

The Mechanical Interaction of Clad and Base Metal for Molten Salt Reactor Structural Components

2018 ◽  
Author(s):  
M. C. Messner ◽  
V.-T. Phan ◽  
R. I. Jetter ◽  
T.-L. Sham
Keyword(s):  
High Temperature ◽  
Molten Salt ◽  
Mechanical Response ◽  
Base System ◽  
Molten Salt Reactor ◽  
Structural Components ◽  
Mechanical Interaction ◽  
Base Materials ◽  
Creep Fatigue ◽  
Axisymmetric Structures

Cladding structural components with a corrosion resistant material may greatly extend the design life of molten salt reactor concepts. A complete design methodology for such cladded, high temperature nuclear components will require addressing many issues: fabrication, corrosion resistance, metallurgical interaction, and the mechanical interaction of the clad and base materials under load. This work focuses on the final issue: the mechanical interaction of the base and clad under creep-fatigue conditions. Depending on the relative mechanical properties of the two materials the clad may substantially influence the long-term cyclic response of the structural system or its effect might be negligible. To quantify the effect of different clad material properties we develop an efficient method for simulating pressurized cladded components in the limiting case where the section of interest is far from structural discontinuities. Using this method we evaluate the mechanics of the clad/base system and identify different regimes of mechanical response. The focus is on situations relevant to high temperature nuclear components: thermal-cyclic Bree-type problems and similar axisymmetric structures. The insights gained from these structural studies will form the basis for developing design rules for high-temperature, nuclear, cladded components.

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