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Nan Hu

Bio: Nan Hu is an academic researcher from South China University of Technology. The author has contributed to research in topics: Bridge (interpersonal) & Buckling. The author has an hindex of 15, co-authored 44 publications receiving 1070 citations. Previous affiliations of Nan Hu include Michigan State University & Central South University.

Papers
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Journal ArticleDOI
TL;DR: A design approach inspired by the stereocilia bundles of a cochlea that uses a hierarchical assembly of interfacial nanowires to retard penetrating cracking and create a structured surface that outperforms its flat counterparts in stretchability and maintains high sensitivity in response to external stimuli.
Abstract: Current metal film-based electronics, while sensitive to external stretching, typically fail via uncontrolled cracking under a relatively small strain (~30%), which restricts their practical applications. To address this, here we report a design approach inspired by the stereocilia bundles of a cochlea that uses a hierarchical assembly of interfacial nanowires to retard penetrating cracking. This structured surface outperforms its flat counterparts in stretchability (130% versus 30% tolerable strain) and maintains high sensitivity (minimum detection of 0.005% strain) in response to external stimuli such as sounds and mechanical forces. The enlarged stretchability is attributed to the two-stage cracking process induced by the synergy of micro-voids and nano-voids. In-situ observation confirms that at low strains micro-voids between nanowire clusters guide the process of crack growth, whereas at large strains new cracks are randomly initiated from nano-voids among individual nanowires. Metal film-based electronics usually fail via uncontrolled cracking at small strains. Here, the authors design a micro-/nano-structured surface with bundled flexible nanowires onto which a metal film can stretch more than a regular flat surface, retard penetrating cracks and remain sensitive.

315 citations

Journal ArticleDOI
TL;DR: In this article, the authors highlight the recent advances in buckling-induced smart applications and explain why buckling responses have certain advantages and are especially suitable for these particular applications, and identify potential research avenues and emerging trends for using buckling and other elastic instabilities for future innovations.
Abstract: A paradigm shift has emerged over the last decade pointing to an exciting research area dealing with the harnessing of elastic structural instabilities for ‘smart’ purposes in a variety of venues. Among the different types of unstable responses, buckling is a phenomenon that has been known for centuries, and yet it is generally avoided through special design modifications. Increasing interest in the design of smart devices and mechanical systems has identified buckling and postbuckling response as a favorable behavior. The objective of this topical review is to showcase the recent advances in buckling-induced smart applications and to explain why buckling responses have certain advantages and are especially suitable for these particular applications. Interesting prototypes in terms of structural forms and material uses associated with these applications are summarized. Finally, this review identifies potential research avenues and emerging trends for using buckling and other elastic instabilities for future innovations.

273 citations

Journal ArticleDOI
TL;DR: It is demonstrated that the proposed asymmetric multimodal actuation enables a plethora of novel applications ranging from the basic 1D/2D active structures with asymmetric shape-shifting to biomimetic crawling robots, swimming robots with efficient dynamic performance and 2D metamaterials with tunable properties.
Abstract: Magnetic-responsive composites that consist of a soft matrix embedded with hard-magnetic particles have recently been demonstrated as robust soft active materials for fast-transforming actuation. H...

115 citations

Journal ArticleDOI
TL;DR: In this article, the authors provide a brief historical review of the HSR development in China along with emerging design issues, including design concepts and structural dimensions of two typical spans, including the superstructure, substructure as well as the auxiliary facilities on the bridge deck.

102 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide a state-of-the-art review on the design practice of these special spans in the high-speed rail (HSR) projects of China.

95 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: In this paper, a magnetic shape memory polymer composite is reported to achieve multiple shape manipulations in one material system, including reprogrammable, untethered, fast, and reversible shape transformation and locking.
Abstract: Shape-programmable soft materials that exhibit integrated multifunctional shape manipulations, including reprogrammable, untethered, fast, and reversible shape transformation and locking, are highly desirable for a plethora of applications, including soft robotics, morphing structures, and biomedical devices. Despite recent progress, it remains challenging to achieve multiple shape manipulations in one material system. Here, a novel magnetic shape memory polymer composite is reported to achieve this. The composite consists of two types of magnetic particles in an amorphous shape memory polymer matrix. The matrix softens via magnetic inductive heating of low-coercivity particles, and high-remanence particles with reprogrammable magnetization profiles drive the rapid and reversible shape change under actuation magnetic fields. Once cooled, the actuated shape can be locked. Additionally, varying the particle loadings for heating enables sequential actuation. The integrated multifunctional shape manipulations are further exploited for applications including soft magnetic grippers with large grabbing force, reconfigurable antennas, and sequential logic for computing.

319 citations

Journal ArticleDOI
TL;DR: A snapping mechanical metamaterial is designed, which exhibits a sequential snap-through behavior under tension, and can be altered by tuning the architecture of the snapping segments to achieve a range of nonlinear mechanical responses, including monotonic, S-shaped, plateau, and non-monotonic snap-Through behavior.
Abstract: A snapping mechanical metamaterial is designed, which exhibits a sequential snap-through behavior under tension. The tensile response of this mechanical metamaterial can be altered by tuning the architecture of the snapping segments to achieve a range of nonlinear mechanical responses, including monotonic, S-shaped, plateau, and non-monotonic snap-through behavior.

312 citations

Journal ArticleDOI
TL;DR: In this article, the authors highlight the recent advances in buckling-induced smart applications and explain why buckling responses have certain advantages and are especially suitable for these particular applications, and identify potential research avenues and emerging trends for using buckling and other elastic instabilities for future innovations.
Abstract: A paradigm shift has emerged over the last decade pointing to an exciting research area dealing with the harnessing of elastic structural instabilities for ‘smart’ purposes in a variety of venues. Among the different types of unstable responses, buckling is a phenomenon that has been known for centuries, and yet it is generally avoided through special design modifications. Increasing interest in the design of smart devices and mechanical systems has identified buckling and postbuckling response as a favorable behavior. The objective of this topical review is to showcase the recent advances in buckling-induced smart applications and to explain why buckling responses have certain advantages and are especially suitable for these particular applications. Interesting prototypes in terms of structural forms and material uses associated with these applications are summarized. Finally, this review identifies potential research avenues and emerging trends for using buckling and other elastic instabilities for future innovations.

273 citations

Journal ArticleDOI
TL;DR: In this article, a critical review is presented to systematically summarize the recent advance of flexible PVDF based piezoelectric nanogenerators in the aspects of incorporating various nanofillers, structural design, optimizing fabrication techniques and energy harvesting application.

258 citations