Action-at-a-distance metamaterials: Distributed local actuation through far-field global forces

The main aim of the paper is to evaluate the mechanical behavior or lattice specimens subjected to quasi-static and dynamic compression tests. Both regular and three different variants of SS 316L lattice structures with gradually changed topologies (discrete, increase and decrease) have been successfully designed and additively manufactured with the use of the selective laser melting technique. The fabricated structures were subjected to geometrical quality control, microstructure analysis, phase characterization and compression tests under quasi-static and dynamic loading conditions. The mismatch between dimensions in the designed and produced lattices was noticed. It generally results from the adopted technique of the manufacturing process. The microstructure and phase composition were in good agreement with typical ones after the additive manufacturing of stainless steel. Moreover, the relationship between the structure relative density and its energy absorption capacity has been defined. The value of the maximum deformation energy depends on the adopted gradient topology and reaches the highest value for a gradually decreased topology, which also indicates the highest relative density. However, the highest rate of densification was observed for a gradually increasing topology. In addition, the results show that the gradient topology of the lattice structure affects the global deformation under the loading. Both, static and dynamic loading resulted in both barrel- and waisted-shaped deformation for lattices with an increasing and a decreasing gradient, respectively. Lattice specimens with a gradually changed topology indicate specific mechanical properties, which make them attractive in terms of energy absorption applications.

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“…These two lattice structures showed narrow-waisted and barrel-shaped deformations. A similar relationship was noticed by Hedayati et al [57].…”

Section: Compression Tests Under Impact Loading Conditionssupporting

confidence: 88%

Investigations on the Mechanical Response of Gradient Lattice Structures Manufactured via SLM

Sienkiewicz

Płatek

Jiang

et al. 2020

Metals

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“…Page 10 of 37 AUTHOR SUBMITTED MANUSCRIPT -SMS-107709 .R1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 A c c e p t e d M a n u s c r i p t 11 where η is non-negative consistency coefficient. The superscript D indicates deviatoric component of gp T that has been assumed to contribute in the plastic evolution.…”

Section: Ii) Mechanism Of Cold Programmingmentioning

confidence: 99%

“…Their experimental and numerical results indicated that the proposed lattices exhibited extreme Poisson's-ratio variations between -0.7 and 0.5 over large tensile deformations up to 50%. Hedayati et al [11] proposed action-at-adistance 3D printed mechanical metamaterials by grading designs of auxetic and conventional unit cells with changing Poisson's ratios. Rafsanjani et al [13] proposed a multi-stable 2-D mechanical metamaterial comprising a periodic arrangement of snapping units with tunable tensile behavior.…”

Section: Introductionmentioning

confidence: 99%

4D printed tunable mechanical metamaterials with shape memory operations

Bodaghi

Liao

2019

Smart Mater. Struct.

110

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A B S T R A C TThe aim of this paper is to introduce tunable continuous-stable metamaterials with reversible thermomechanical memory operations by four-dimensional (4D) printing technology. They are developed based on an understanding on glassy-rubbery behaviors of shape memory polymers and hot/cold programming derived from experiments and theory. Fused decomposition modeling as a well-known 3D printing technology is implemented to fabricate mechanical metamaterials. They are experimentally tested revealing elastic-plastic and hyper-elastic behaviors in low and high temperatures at a large deformation range. A computational design tool is developed by implementing a 3D phenomenological constitutive model coupled with a geometrically non-linear finite element method. Governing equations are then solved by an elastic-predictor plastic-corrector return map procedure along with the Newton-Raphson and Riks techniques to trace non-linear equilibrium path. A tunable reversible mechanical metamaterial unit with bistable memory operations is printed and tested experimentally and numerically. By a combination of cold and hot programming, the unit shows potential applications in mimicking electronic memory devices like tactile displays and designing surface adaptive structures. Another design of the unit shows potentials to serve in designing self-deployable bio-medical stents. Experiments are also conducted to demonstrate potential applications of cold programming for introducing recoverable rolling-up chiral metamaterials and load-resistance supportive auxetics.

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“…Another emerging design strategy explores the capacity of the internal architecture 2 of 12 to transfer local deformation through the metamaterial. In this case of so-called action-at-a-distance metamaterials, the internal architecture may define the involved geometrical changes observed on the surface of the metamaterial in response to applied mechanical stimuli [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Planar Mechanical Metamaterials with Embedded Permanent Magnets

Slesarenko

2020

Materials

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The design space of mechanical metamaterials can be drastically enriched by the employment of non-mechanical interactions between unit cells. Here, the mechanical behavior of planar metamaterials consisting of rotating squares is controlled through the periodic embedment of modified elementary cells with attractive and repulsive configurations of the magnets. The proposed design of mechanical metamaterials produced by three-dimensional printing enables the efficient and quick reprogramming of their mechanical properties through the insertion of the magnets into various locations within the metamaterial. Experimental and numerical studies reveal that under equibiaxial compression various mechanical characteristics, such as buckling strain and post-buckling stiffness, can be finely tuned through the rational placement of the magnets. Moreover, this strategy is shown to be efficient in introducing bistability into the metamaterial with an initially single equilibrium state.

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Action-at-a-distance metamaterials: Distributed local actuation through far-field global forces

Cited by 43 publications

References 36 publications

Investigations on the Mechanical Response of Gradient Lattice Structures Manufactured via SLM

Investigations on the Mechanical Response of Gradient Lattice Structures Manufactured via SLM

4D printed tunable mechanical metamaterials with shape memory operations

Planar Mechanical Metamaterials with Embedded Permanent Magnets

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