Design and testing of a passively adaptive inlet

Arena, Gaetano; Groh, Rainer; Theunissen, Raf; Pirrera, Alberto

doi:10.1088/1361-665x/aacf79

Cited by 15 publications

(8 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By increasing the amount of compression beyond the limit point on the broken-away path, the inlet can be transformed into a bistable structure that remains closed once the airflow is reduced. The greater the applied compression, the higher the airspeed required to actuate snap-through; the system's parameters can be tailored to meet specific operating requirements (see [98,99] for further details).…”

Section: Adaptive Structuresmentioning

confidence: 99%

Happy Catastrophe: Recent Progress in Analysis and Exploitation of Elastic Instability

Champneys

Dodwell

Groh

et al. 2019

Front. Appl. Math. Stat.

View full text Add to dashboard Cite

A synthesis of recent progress is presented on a topic that lies at the heart of both structural engineering and non-linear science. The emphasis is on thin elastic structures that lose stability subcritically-without a nearby stable post-buckled state-a canonical example being a uniformly axially-loaded cylindrical shell. Such structures are hard to design and certify because imperfections or shocks trigger buckling at loads well below the threshold of linear stability. A resurgence of interest in structural instability phenomena suggests practical stability assessments require stochastic approaches and imperfection maps. This article surveys a different philosophy; the buckling process and ultimate post-buckled state are well-described by the perfect problem. The significance of the Maxwell load is emphasized, where energy of the unbuckled and fully-developed buckle patterns are equal, as is the energetic preference of localized states, stable, and unstable versions of which connect in a snaking load-deflection path. The state of the art is presented on analytical, numerical and experimental methods. Pseudo-arclength continuation (path-following) of a finite-element approximation computes families of complex localized states. Numerical implementation of a mountain-pass energy method then predicts the energy barrier through which the buckling process occurs. Recent developments also indicate how such procedures can be replicated experimentally; unstable states being accessed by careful control of constraints, and stability margins assessed by shock sensitivity experiments. Finally, the fact that subcritical instabilities can be robust, not being undone by reversal of the loading path, opens up potential for technological exploitation. Several examples at different length scales are discussed; a cable-stayed prestressed column, two examples of adaptive structures inspired by morphing aeroelastic surfaces, and a model for a functional auxetic material.

show abstract

Section: Adaptive Structuresmentioning

confidence: 99%

Happy Catastrophe: Recent Progress in Analysis and Exploitation of Elastic Instability

Champneys

Dodwell

Groh

et al. 2019

Front. Appl. Math. Stat.

View full text Add to dashboard Cite

show abstract

“…However, this narrative has been challenged more recently, and instabilities have been exploited for novel functionalities. This has led to the creation of well-behaved nonlinear structures [5] such as shape-adaptive structures [6][7][8][9], deployable structures [10][11][12], zero or negative stiffness structures [13,14], energy harvesters [15], as well as non-destructive testing techniques [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Structural function from sequential, interacting elastic instabilities

et al. 2023

Self Cite

View full text Add to dashboard Cite

Elastic instabilities have traditionally been considered a failure mechanism; however, recent years have seen numerous studies exploiting instabilities as a means to achieve structural functionality. By contrast, interacting instabilities and compound buckling are still largely viewed as a failure mechanism. In this paper, we show that interacting instabilities can also be exploited to achieve bespoke functionality. We focus on ‘sequential instabilities’, whose associated critical points cannot both lie on a fundamental equilibrium path. We obtain sequential instabilities by combining canonical bifurcations, (e.g. limit point, pitchfork) as building-blocks. Initially, this concept is explored through simple bar-and-spring models that are found to have several properties not exhibited by the building blocks from which they are constructed. Further, the utility of the building block approach, and that of sequential, interacting instabilities, is demonstrated through the development of a morphing structure which must rapidly deploy after a critical input displacement is attained, and meet specific post-deployment stiffness requirements. Two design concepts are proposed, each comprising building blocks to mirror the fundamental working principles identified through the bar-and-spring models. Finite-element models of the design solutions are presented, demonstrating how the designs positively use sequential, interacting instabilities in order to meet the challenging requirements of the application. This work extends the contextual framework of instabilities that can be used to create structures with novel functionality.

show abstract

“…From a macroscopic point of view, recent studies have indicated that a flexible material can be adopted to control the fluid (including both gas and liquid) flow in fluidic devices. − In this kind of flexible fluidic device, the fluid flow and the wall deformation are coupled to each other. Comparing with the rigid fluidic device, the flexible wall plays an important role in solid–fluid coupling behaviors, which might further be harnessed for the control of the fluid flow process.…”

Section: Introductionmentioning

confidence: 99%

Snap-through in Graphene Nanochannels: With Application to Fluidic Control

Jiao

Liu

2020

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Recent studies on the structure and transport behaviors of water confined within lamellar graphene have attracted intense interest in filtration technology, but the mechanism of water transport in complex membrane nanostructures remains an open question. For example, similar systems but at much larger scales have indicated that the instabilities of an elastic structure, such as snap-through, play an essential role in controlling the fluid flow. Graphene sheets, which have an atomic thickness, often appear highly wrinkled in nanofluidic devices and so are vulnerable to elastic instabilities. However, it remains unclear how does the flexible wrinkled structure affect the transport of water and filtration efficiency or whether such an effect can be exploited in devices. In this work, we explore the flow-induced snap-through in graphene nanochannels by combining molecular simulations with the theoretical analysis. We further demonstrate its applications to passive control of fluid flow and to ion/molecule selection. By introducing a flexible arch embedded within a graphene nanochannel, we observe the “snap” of the arched graphene wall from one stable state to another by varying the fluid flux (i.e., velocity); the critical velocity of this snap transition is found to depend nonmonotonically on the geometric size of the channel and the arch. We also demonstrate reversible snap-through by fixing the end parts of the flexible arch. These results suggest the potential of flow-induced snap-through in graphene-based nanochannels for ion/molecule selection applications in, for example, the design of a foul-resistant, easy-to-clean, reusable filter membrane.

show abstract

Design and testing of a passively adaptive inlet

Cited by 15 publications

References 24 publications

Happy Catastrophe: Recent Progress in Analysis and Exploitation of Elastic Instability

Happy Catastrophe: Recent Progress in Analysis and Exploitation of Elastic Instability

Structural function from sequential, interacting elastic instabilities

Snap-through in Graphene Nanochannels: With Application to Fluidic Control

Contact Info

Product

Resources

About