On-demand contactless programming of nonlinear elastic moduli in hard magnetic soft beam based broadband active lattice materials

Abstract

Engineered honeycomb lattice materials with high specific strength and stiffness along with the advantage of programmable direction-dependent mechanical tailorability are being increasingly adopted for various advanced multifunctional applications. To use these artificial microstructures with unprecedented mechanical properties in the design of different application-specific structures, it is essential to investigate the effective elastic moduli and their dependence on the microstructural geometry and the physics of deformation at the elementary level. While it is possible to have a wide range of effective mechanical properties based on their designed microstructural geometry, most of the recent advancements in this field lead to passive mechanical properties, meaning it is not possible to actively modulate the lattice-level properties after they are manufactured. Thus the on-demand control of mechanical properties is lacking, which is crucial for a range of multi-functional applications in advanced structural systems. To address this issue, we propose a new class of lattice materials wherein the beam-level multi-physical deformation behavior can be exploited as a function of external stimuli like magnetic field by considering hard magnetic soft (HMS) beams. More interestingly, effective property modulation at the lattice level would be contactless without the necessity of having a complex network of electrical circuits embedded within the microstructure. We have developed a semi-analytical model for the nonlinear effective elastic properties of such programmable lattice materials under large deformation, wherein the mechanical properties can be modulated in an expanded design space of microstructural geometry and magnetic field. The numerical results show that the effective properties can be actively modulated as a function of the magnetic field covering a wide range (including programmable state transition with on-demand positive and negative values), leading to the behavior of soft polymer to stiff metals in a single lattice microstructure according to operational demands.

Current developments in elastic and acoustic metamaterials science

“…The effective elastic moduli can be actively controlled in piezoelectric lattices as a function of voltage, leading to stiffer or softer behaviour of a single lattice architecture in an on-demand framework as per operational requirements, even after its fabrication [33,34]. A magnetic field can lead to on-demand modulation of effective elastic properties in a contactless framework [35,36]. Programmability of thermal expansion and load-bearing capacity can be attained simultaneously in multi-phase metamaterials containing framework structures [37].…”

Hard magnetics and soft materials—a synergy

“…Figure 14 illustrates several modeling frameworks employed for the analysis of hMS beams in the existing literature. Consider the following recent studies in hMS beams for further [302][303][304][305][306][307][308][309]. The detailed models for hMS beams serve as an integral part of the broader computational frameworks designed for hMSM characterization and analysis.…”

Pneumatic elastostatics of multi-functional inflatable lattices: realization of extreme specific stiffness with active modulation and deployability

“…Artificially engineered materials can achieve a wide range of tailor-made multi-functional abilities which may not always be available in naturally occurring materials [1][2][3][4][5]. Their micro-scale design can present unprecedented and unconventional, yet useful, properties like ultra-lightweight characteristics [6][7][8][9], shape programming [6,10], crushing resistance and high specific energy absorption [11][12][13][14], auxetic properties [15][16][17][18][19], negative elastic moduli [20][21][22], meta-fluid characteristics [23,24], negative mass density [25,26], tunable wave propagation characteristics and vibration control [27][28][29], programmable constitutive laws [30][31][32], active mechanical property modulation [33][34][35][36][37] and many other multiphysical properties [38][39][40][41][42]. The use of such metamaterials in structural systems can result in the most optimal use of materials along with fulfilling multiple other structural demands simultaneously.…”