Designing and Harnessing the Metastable States of a Modular Metastructure for Programmable Mechanical Properties Adaptation

Abstract

Recent studies on periodic metamaterial systems have shown that remarkable properties adaptivity and versatility are often the products of exploiting internal, coexisting metastable states. Motivated by this concept, this research develops and explores a local-global design framework wherein macroscopic system-level properties are sought according to a strategic periodic constituent composition and assembly. To this end and taking inspiration from recent insights in studies of multiphase composite materials and cytoskeletal actin networks, this study develops adaptable metastable modules that are assembled into modular metastructures, such that the latter are invested with synergistic features due to the strategic module development and integration. Using this approach, it is seen that modularity creates an accessible pathway to exploit metastable states for programmable metastructure adaptivity, including a near-continuous variation of mechanical properties or stable topologies and adjustable hysteresis. A model is developed to understand the source of the synergistic characteristics, and theoretical findings are found to be in good agreement with experimental results. Important design-based questions are raised regarding the modular metastructure concept, and a genetic algorithm (GA) routine is developed to elucidate the sensitivities of the properties variation with respect to the statistics amongst assembled module design variables. To obtain target multifunctionality and adaptivity, the routine discovers that particular degrees and types of modular heterogeneity are required. Future realizations of modular metastructures are discussed to illustrate the extensibility of the design concept and broad application base.

On the wave propagation analysis and supratransmission prediction of a metastable modular metastructure for non-reciprocal energy transmission

“…3, we noticeably observed the correlation between dynamics of the first bistable element with respect to the transmission ratio (TR) under forward actuation. This is mainly for two reasons: first is the weak coupling between the individual units (to maintain adaptable and metastable characteristics, strong coupling is not desired [33] [34]) and second is because the driving frequency is inside the stopband, vibration is prone to be localized closer to the excitation initially. Therefore, we propose to predict the onset of supratransmission of the fully nonlinear metsatructure by analyzing an equivalent but simplified mathematical model that only retains the nonlinear element of the first unit while linearizing the rest of the chain.…”

“…V, influence of some key parameters on the threshold amplitude to trigger supratransmission is explored. In general, for a fixed global displacement , a chain of metastable modules can have up to 2 metastable states (internal configurations), Figure 1(c) [33] [34]. Starting from one of the metastable states, equations of motion for the ℎ metastable module can be expressed as:…”

A New Architecture of Morphing Wing Based on Hyperelastic Materials and Metastructures With Tunable Stiffness

“…In addition, metamaterial or metastructure is a class of synthetic materials and its macroscopic properties can be artificially controlled to obtain a new type of material or structure with exotic properties, such as mechanical metamaterial, acoustic metamaterial, and thermal metamaterial (Harne et al, 2016). The special properties of metamaterial or metastructure are achieved by engineering its cellular architecture and chemical composition (Cui et al, 2010).…”

Harnessing the anisotropic multistability of stacked-origami mechanical metamaterials for effective modulus programming

“…Relevant studies suggested that multistability can be exploited to achieve shape morphing (Daynes and Weaver, 2013;Haghpanah et al, 2016;Lachenal et al, 2013;Sun et al, 2016), broadband vibration control (Johnson et al, 2014(Johnson et al, , 2013Yang et al, 2014), robust sensing (Harne and Wang, 2014), energy harvesting (Daqaq et al, 2014;Harne and Wang, 2013), impact energy trapping (Frenzel et al, 2016;Puglisi and Truskinovsky, 2002;Shan et al, 2015), and even non-reciprocal wave propagations (Bilal et al, 2017;Nadkarni et al, 2016;Raney et al, 2016). In particular, stiffness adaptation has also been demonstrated on multistable structures such as the asymmetric fiber composite laminates (Arrieta et al, 2014;Kuder et al, 2015) and muscle inspired modular assemblies (Harne et al, 2015;Wu et al, 2016). If the effective stiffness or modulus is designed to be different among these stable states, one only needs to supply the energy to initiate a switch between stable states to achieve a sustained stiffness adaptation.…”