3D‐Printed Soft and Hard Meta‐Structures with Supreme Energy Absorption and Dissipation Capacities in Cyclic Loading Conditions

Abstract

The main objective of this article is to introduce novel 3D bio‐inspired auxetic meta‐structures printed with soft/hard polymers for energy absorption/dissipation applications under single and cyclic loading–unloading. Meta‐structures are developed based on understanding the hyper‐elastic feature of thermoplastic polyurethane (TPU) polymers, elastoplastic behavior of polyamide 12 (PA 12), and snowflake inspired design, derived from theory and experiments. The 3D meta‐structures are fabricated by multi‐jet fusion 3D printing technology. The feasibility and mechanical performance of different meta‐structures are assessed experimentally and numerically. Computational finite element models (FEMs) for the meta‐structures are developed and verified by the experiments. Mechanical compression tests on TPU auxetics show unique features like large recoverable deformations, stress softening, mechanical hysteresis characterized by non‐coincident compressive loading–unloading curve, Mullins effect, cyclic stress softening, and high energy absorption/dissipation capacity. Mechanical testing on PA 12 meta‐structures also reveals their elastoplastic behavior with residual strains and high energy absorption/dissipation performance. It is shown that the developed FEMs can replicate the main features observed in the experiments with a high accuracy. The material‐structural model, conceptual design, and results are expected to be instrumental in 3D printing tunable soft and hard meta‐devices with high energy absorption/dissipation features for applications like lightweight drones and unmanned aerial vehicles (UAVs).

Shape memory meta-laminar jamming actuators fabricated by 4D printing

“…The behaviour of the auxetic structure is different from others due to its mechanical properties and zero Poisson's ratio in terms of absorbing energy. 42 The recovery time of all meta-structures is recorded as reported in Fig. 8(e).…”

“…The maximum temperature at which the structures recover their shape is around 71±2 °C for compressed ones and 68±2 °C for bent specimens. The behaviour of the auxetic structure is different from others due to its mechanical properties and zero Poisson's ratio in terms of absorbing energy [42]. The recovery time of all metastructures is recorded as reported in Figure 8(e).…”

Parrot Beak‐Inspired Metamaterials with Friction and Interlocking Mechanisms 3D/4D Printed in Micro and Macro Scales for Supreme Energy Absorption/Dissipation

“…[ 9 ] In general, metamaterials can be divided into several main groups, including positive Poisson's ratio (PPR) structures such as honeycombs, [ 10–12 ] zero Poisson's ratio (ZPR), [ 13,14 ] buckling metamaterials, [ 15,16 ] and negative indices mechanical metamaterials. [ 17–23 ]…”

“…[9] In general, metamaterials can be divided into several main groups, including positive Poisson's ratio (PPR) structures such as honeycombs, [10][11][12] zero Poisson's ratio (ZPR), [13,14] buckling metamaterials, [15,16] and negative indices mechanical metamaterials. [17][18][19][20][21][22][23] More related to our work, energy-absorbing structures are often designed using repeatable nonlinear buckling effects to achieve recoverable structures. [24] Most traditional dampers have cylindrical shapes, [25] and this study will also focus on cylindrical metamaterials designed by repeating the unit cells along the radial and axial directions.…”

Energy absorbing 4D printed meta-sandwich structures: load cycles and shape recovery

“…With reference to energy absorption, (Youse et al, 2022) proposed a high-performance auxetic metastructure with an original design inspired by a snow ake. Two materials with distinct mechanical characteristics were tested: the soft hyper-elastic TPU, capable of withstanding large deformations, and the hard elasto-plastic PA12, more performing in terms of energy absorption.…”