In the past few centuries, with the amazing advances in science and technology, the requirements for engineered materials have become more and more specific [1,2] and novel [3,4]. Fortunately, the required mechanical properties can be achieved through certain processing programs and structural designs [5-8]. The idea has effectively implemented negative Poisson’s ratio (NPR) [9-12] lattice structures in many fields. Mechanical metamaterials are a class of architected materials with superior physical properties beyond nature [13]. Through the rational design of their microstructures and material [14], they have counterintuitive properties that can achieve unique and uncommon mechanical properties such as negative Poisson’s ratio [15], graded stiffness [16], non-reciprocal response [17], negative coefficient of thermal expansion [18-20], energy harvesting [21-26], among others. Mechanical metamaterials are an innovative field focusing on the interplay between material and structure [27]. The development has shifted towards 2D and 3D metamaterials, allowing programmability and unique properties [28,29]. These materials can be adjusted through deformation, controlled by internal or external stimuli, enhancing flexibility and adaptability [30,31]. Using modular structures is highly effective for creating metamaterials with features like adjustable negative Poisson’s ratio [32], demonstrating the vast potential of this emerging field. 
As a special type of mechanical metamaterials, auxetic metamaterials with negative Poisson ratio can expand their volume when stretched, and vice versa. The first NPR materials were reported in the 1870s. Voigt’s [33] experimental calculation determined that the Poisson’s ratio of pyrite is υ ≈ - 1/7. Lake et al. [34,35] designed artificial NPR structures in foam materials and computed the Poisson’s ratio as υ ≈ - 0.7 for the first time in 1987. Evans et al. [36,37] then began using the proprietary term “auxetic”, which means that the material expands when stretched but does not signify “compression” in the literal sense. Since this term is universally accepted, it can also referred to NPR structural materials as “auxetic metamaterials” [38]. Auxetic materials show potential in the biomedical field [39], aerospace [40], protective devices [41], strain sensors [42], and fasteners [43]. According to the geometrical relations of the auxetic unit cell, the preponderant topological NPR lattice structures are re-entrant [44] and chiral structures [45-47]. Although the rotating rigid square elements cannot be referred to as lattices, the structure can also be considered to originate from a unit cell array and exhibit NPR behavior [48,49].
Auxetic materials play important roles in various fields. For example, in medical and biomedical applications, auxetic metamaterials hold great promise, particularly as materials for vascular stents [50,51]. Traditional vascular stent materials have certain limitations and deficiencies, whereas auxetic metamaterials, with their excellent mechanical properties and biocompatibility, can offer better elasticity and adaptability. This can reduce complications and restenosis after stent implantation, thereby improving patients' quality of life [52]. In the aerospace sector, auxetic metamaterials can be used as sandwich materials to enhance the stability and structural rigidity of aircraft wings [53]. Their unique properties allow them to provide additional support and stability when wings are subjected to wind loads, helping to reduce vibrations and instabilities during high-speed flights and thus improving flight safety and efficiency [54]. In the automotive industry, auxetic metamaterials can be employed to construct sandwich beams as protective devices, safeguarding drivers and passengers [55]. The design and manufacture of these beams can leverage the energy absorption and distribution characteristics of auxetic metamaterials, effectively cushioning and reducing the impact forces in vehicle collisions [56]. This would significantly enhance vehicle safety and reduce injury in accidents. Auxetic metamaterials also have immense potential in mitigating explosive impacts. Sandwich panel structures can effectively absorb and disperse energy, thus reducing damage to the surrounding environment and structures from blasts [57]. The unique properties of auxetic metamaterials make them ideal for designing and manufacturing explosion-proof equipment and structures, enhancing safety and minimizing the damage of blast incidents.
The unit cells of metamaterials can be similar while the assembled structures in the overall phase are relatively different. In the unit phase, some existing unit cell structures can be chosen, such as re-entrant hexagon structure [58], double arrow structure [59], star-shaped structure [60], and missing rib structure [61], etc. For design optimization, or to create a new type of unit cell structure to achieve specific goals, the microstructures determine local performance. In the overall phase, the performance resembles homogenous materials. Specific mechanical behaviors can be achieved through different combinations of the same unit cell or particular combinations between different units [62]. And metamaterials’ mechanical performance is between the natural materials dominated by their intrinsic material properties and the artificial structures influenced by their structural characteristics. Considering that the performance of mechanical metamaterials is mainly determined by unit cells, their tunability is typically achieved by rational design and optimization of the unit cells. This makes it possible to obtain structures with desirable mechanical properties through designing models. Therefore, the mechanical properties of mechanical metamaterials are usually satisfied through the design and optimization of their microstructure units, as well as different combinations. 
While beam-based lattice structures have been the mainstay in the field of mechanical metamaterials over the past two decades, their structural efficiency has been less than optimal, preventing them from reaching the theoretical stiffness and strength limits, known as the Hashin-Shtrikman and Suquet upper bounds [63]. These bounds represent the maximum potential for any isotropic cellular topology. Plate-based designs, on the other hand, are theoretically capable of reaching these upper bounds, but practical implementation has been hindered by substantial manufacturing obstacles. Furthermore, its most notable characteristic is the authenticity exhibited in the wall thickness. Upon vertical compression of the tubular structure, a contraction of the tube wall occurs, leading to a reduction in the outer diameter and an increase in the inner diameter. This novel characteristic of the proposed auxetic tubular structures significantly broadens the potential scope of applications for such structures.
In this research, a plate-based auxetic cylindrical metamaterial was proposed based on the star-shaped structure. The auxetic behavior, effective stiffness, and effective yield strength of the cylinder were validated through in situ compression tests and Finite Element Method (FEM) simulations. In comparison to beam-based lattice structures, the plate-based auxetic cylindrical metamaterial was demonstrated to have considerable enhancement in both Young's modulus and strength. 
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