3D printing shape memory polymer of laminated multi-component metamaterial towards optimization of auxetic and shape recovery behaviors

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With the development of mechanical metamaterials, structures with large and nonlinear deformations have attracted great research passions for their increasingly applications. Although it has been studied for decades, the mechanics of conflict between large deformation with non-buckling has not been well understood. In this study, a new type of mechanical metamaterial, of which the large deformation is achieved without buckling, has been proposed to achieve the zero Poisson’s ratio using fractal design. Effects of fractal iteration ( i ) and connection angle ( α ) on the Poisson’s ratio and mechanical stress-strain behaviors of 3D printing mechanical metamaterial were studied by finite element analysis and experimental tests. Finally, constitutive relationships among loading force, Poisson’s ratio, iteration time and connection angle have been explored and discussed to achieve a large and non-buckling deformation.

Section: Feamentioning

confidence: 97%

Fractal design of 3D-printing mechanical metamaterial undergoing tailorable zero Poisson’s ratio

Liu,

Lu,

Lau

2023

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“…Liu et al [133] have developed a multi-component layered metamaterial that can provide a customizable strain energy release rate for optimizing auxetic and form recovery behaviors. The material incorporated viscoelastic and elastic SMPs and was experimentally tested for auxetic, yielding, and shape recovery behaviors, which agreed with finite element method results.…”

Section: D Printing Of Auxetic Structuresmentioning

confidence: 99%

4D printing of fiber-reinforced auxetic structures: the building blocks: a review

Karima,

Habibi,

Laperrière

2024

Four-dimensional (4D) printing has recently received much attention in the field of smart materials. It concerns using additive manufacturing to obtain geometries that can change shape under the effect of different stimuli. Such a technique enables the fabrication of 3D printed parts with the additional functionality of scalable, programmable, and controllable part shapes over time. This review provides a comprehensive examination of advances in the field of 4D printing, emphasizing the integration of fiber reinforcement and auxetic structures as crucial building blocks. The incorporation of fibers enhances structural integrity, while auxetic design principles contribute unique mechanical properties, such as negative Poisson's ratio and great potential for energy absorption due to their specific deformation mechanisms. Therefore, they present potential applications in aerospace, drones, and robotics.The objective of this review article is first to describe the distinctive properties of shape memory polymers (SMPs), auxetic structures, and composite (fiber-reinforced) materials. A review of applications that use combinations of such materials is also presented when appropriate. The goal is to get a grip on the delicate balance between the different properties achievable in each case. The paper concludes by describing recent advances in 4D printing of fiber-reinforced auxetic structures.

“…Auxetic materials and composites have been used in defence, sports and machine vibration damping applications to improve mechanical and energy absorbing characteristics due to their unique negative Poisson's ratio (NPR) behaviour [1][2][3][4]. It is well known that the re-entrant structure of auxetic materials results in NPR due to which these materials contract in all directions while compressed or stretched in all directions when extension is applied along one of their axes.…”

Section: Introductionmentioning

confidence: 99%

Flexural behaviour of cementitious composites embedded with 3D printed re-entrant chiral auxetic meshes

Zahra,

Asad,

Thamboo

2024

3D printed auxetic metamaterials can be used to make high performing cementitious composites to strengthen existing structures and elements due to their negative Poisson’s ratio behaviour and high energy absorbing characteristics. In this paper, three different re-entrant chiral auxetic (RCA) meshes of various cell geometries and orientations were developed by 3D printing them using poly-lactic acid (PLA) and thermoplastic polyurethane (TPU) filament. The developed meshes were tested under out-of-plane flexure to study their load carrying capacity, ductility and energy absorption characteristics, especially to characterise the best cell orientation. The horizontal cells provided enhanced load carrying and energy absorption characteristics for all three cell geometries for both materials. These RCA meshes were then embedded into low and high strength premix cement mortar matrices to develop Auxetic Cementitious Composites (ACC). In total, forty-two ACC specimens were casted and tested under flexural loading. The results were studied in terms of their failure patterns, load-displacement responses, flexural capacities, ductility and energy absorption. The RCA meshes made of PLA filament showed limited capacity and energy absorption as compared to RCA meshes made of TPU filament due to extended flexibility and resilience provided by TPU meshes. The RCA meshes with a denser cell structure exhibited highest flexural capacity and effective energy absorption of 14,700 kJ/m2 for TPU-RCA mesh embedded into high strength cement mortar matrix. The results obtained in this study have enabled to understand the flexural behaviour of cementitious composites embedded with 3D printed auxetic lattices and to strengthen the existing structures.