Experimentally program large magnitude of Poisson's ratio in additively manufactured mechanical metamaterials

Ling, Bo; Wei, Kai; Wang, Zhonggang; Yang, Xujing; Qu, Zhaoliang; Fang, Daining

doi:10.1016/j.ijmecsci.2020.105466

Cited by 81 publications

(24 citation statements)

References 46 publications

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“…It may also be used as a method to gauge the strain tolerance and fatigue limits of microstructures or machine components subjected to predetermined displacement loads under both static and dynamic conditions. 60,61 Systems with high K ε values are more susceptible to material yielding and failure upon the application of a load than systems with lower values. In Figure 8, figures showing the K ε distribution obtained for uniaxial loading of the Orientation = 0° systems of these three structures are shown, while in Table 4 the maximum K ε values obtained for each orientation and loading type (uniaxial and shear) of each structure are presented.…”

Section: Resultsmentioning

confidence: 99%

A comparison between rotating squares and anti-tetrachiral systems: Influence of ligaments on the multi-axial mechanical response

Mizzi

Sorrentino

Spaggiari

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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Rotating unit systems are one of the most important and well-known classes of auxetic mechanical metamaterials. As their name implies, when loaded, these systems deform primarily via rotation of blocks of material, which may be connected together either directly through joints (or ‘joint-like’ connections made by overlapping vertices of the rotating units) as in the case of rotating rigid polygonal-unit systems or by ligaments/ribs as in the case of chiral honeycombs. In this work, we used Finite Element Analysis to investigate the effect which the presence/absence of ligaments has on the on-axis and off-axis mechanical properties of these systems by analysing two of the most well-known structures which characterise these two cases: the rotating square system and the anti-tetrachiral honeycomb. It was found that while the presence of ligaments has a negligible effect on the on-axis Poisson’s ratio of these systems, it has a profound influence on nearly all other mechanical properties as well as on the off-axis loading behaviour. Systems with ligaments were found to exhibit a high level of anisotropy and also a severely reduced level of stiffness in comparison to their non-ligamented counterparts. On the other hand, the rotating square system suffers from high localized stress-intensities and has a very low strain-tolerance threshold. In addition, an optimized ‘hybrid’ geometry which is specifically designed to capture the best features of both the anti-tetrachiral and rotating square system, was also analysed. This work shows the main differences between ligament-based and non-ligament-based auxetic structures and also highlights the importance of considering the off-axis mechanical response in addition to the on-axis properties when investigating such systems.

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Section: Resultsmentioning

confidence: 99%

A comparison between rotating squares and anti-tetrachiral systems: Influence of ligaments on the multi-axial mechanical response

Mizzi

Sorrentino

Spaggiari

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…The introduction of side panels results in the differences in Poisson’s ratio of CS-based units and the structural model. According to the literature [ 41 ], for the NPR metamaterials, the structural expansion or shrinkage accompanied by the distortion of units near loading end and boundaries. As shown in Figure 6 a, the distortion of top layer units is limited by the top panel at one end.…”

Section: Resultsmentioning

confidence: 99%

A New Polymer-Based Mechanical Metamaterial with Tailorable Large Negative Poisson’s Ratios

et al. 2020

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Mechanical metamaterials have attracted significant attention due to their programmable internal structure and extraordinary mechanical properties. However, most of them are still in their prototype stage without direct applications. This research developed an easy-to-use mechanical metamaterial with tailorable large negative Poisson′s ratios. This metamaterial was microstructural, with cylindrical-shell-based units and was manufactured by the 3D-printing technique. It was found numerically that the present metamaterial could achieve large negative Poisson′s ratios up to −1.618 under uniaxial tension and −1.657 under uniaxial compression, and the results of the following verification tests agreed with simulation findings. Moreover, stress concentration in this new metamaterial is much smaller than that in most of existing re-entrance metamaterials.

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“…In addition, among the various auxetic structures printed, re-entrant structures have displayed the highest Poisson's ratio. A significant contribution was made by Ling et al [79], who realized an auxetic re-entrant triangle and honeycomb structures through FDM. The fabricated structures Fig.…”

Section: Fdmmentioning

confidence: 99%

On the application of additive manufacturing methods for auxetic structures: a review

2021

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Auxetic structures are a special class of structural components that exhibit a negative Poisson's ratio (NPR) because of their constituent materials, internal microstructure, or structural geometry. To realize such structures, specialized manufacturing processes are required to achieve a dimensional accuracy, reduction of material wastage, and a quicker fabrication. Hence, additive manufacturing (AM) techniques play a pivotal role in this context. AM is a layer-wise manufacturing process and builds the structure as per the designed geometry with appreciable precision and accuracy. Hence, it is extremely beneficial to fabricate auxetic structures using AM, which is otherwise a tedious and expensive task. In this study, a detailed discussion of the various AM techniques used in the fabrication of auxetic structures is presented. The advancements and advantages put forward by the AM domain have offered a plethora of opportunities for the fabrication and development of unconventional structures. Therefore, the authors have attempted to provide a meaningful encapsulation and a detailed discussion of the most recent of such advancements pertaining to auxetic structures. The article opens with a brief history of the growth of auxetic materials and later auxetic structures. Subsequently, discussions centering on the different AM techniques employed for the realization of auxetic structures are conducted. The basic principle, advantages, and disadvantages of these processes are discussed to provide an in-depth understanding of the current level of research. Furthermore, the performance of some of the prominent auxetic structures realized through these methods is discussed to compare their benefits and shortcomings. In addition, the influences of geometric and process parameters on such structures are evaluated through a comprehensive review to assess their feasibility for the latermentioned applications. Finally, valuable insights into the applications, limitations, and prospects of AM for auxetic structures are provided to enable the readers to gauge the vitality of such manufacturing as a production method.

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Experimentally program large magnitude of Poisson's ratio in additively manufactured mechanical metamaterials

Cited by 81 publications

References 46 publications

A comparison between rotating squares and anti-tetrachiral systems: Influence of ligaments on the multi-axial mechanical response

A comparison between rotating squares and anti-tetrachiral systems: Influence of ligaments on the multi-axial mechanical response

A New Polymer-Based Mechanical Metamaterial with Tailorable Large Negative Poisson’s Ratios

On the application of additive manufacturing methods for auxetic structures: a review

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