# Co-Design of Mechanical and Vibration Properties of a Star Polygon-Coupled Honeycomb Metamaterial
## 6 Conclusions  
A novel metamaterial is designed to solve the problem of incompatibility between carrying capacity and vibration suppression performance of common metamaterial. The carrying capacity and vibration suppression capability of the proposed metamaterial are analyzed and verified by simulation and experimental methods. The results show that the carrying capacity of the proposed metamaterial is enhanced by adding rings and assembly pins, and a better vibration suppression capacity is further achieved by adjusting the configuration parameters to generate specific bandgaps. The following conclusions can be drawn from this work:  
1. With the design of rings, the stiffness of the SPCHM has increased by 325% compared to that of the IM, while the mass of the SPCHM is only 23.8% heavier than that of the IM. Moreover, the stiffness of the SPCHM with copper pins has further increased by 62% on the basis of the SPCHM, and the mass of the SPCHM with copper pins is 335% heavier than that of the SPCHM. These features indicate a notable improvement in load-bearing capacity.
2. The bandgap properties could be effectively regulated by inserting different sizes and materials of pins, thereby improving the vibration suppression performance. Furthermore, more bandgaps will be generated by changing the number and position of pins.
3. The particle damping method has the advantage of replacing existing materials by designing an equal equivalent density, and it could even be used as a substitute for specific materials that exist in reality. Moreover, this feature makes it possible to adjust the bandgaps continuously, and the good adaptability of particles provides the potential to be applied in engineering applications with high precision requirements.  
For a moving automobile, the vibration frequency range of the vehicle body, which is caused by the engine/motor, tires, and wind noise, is generally from 50 Hz to 3500 Hz [45; 46; 47; 48]. To improve the environmental perception accuracy for safety and comfort control of intelligent vehicles, our future work will concentrate on the development of a vibration suppression bracket for environmental sensor installation based on the proposed metamaterial. Moreover, adding mixed particle damping of different materials to the rings may produce better results, which will also be the direction for further research.  
Conceptualization, J.Y. and X.H.; methodology, J.Y. and X.H.; software, W.L. and Z.W.; validation, W.L., Y.D. and Z.W.; formal analysis, J.Y. and N.F.; investigation, Y.D. and N.F.; resources, Z.W.; data curation, W.L.; writing--original draft preparation, J.Y. and W.L.; writing--review and editing, J.Y. and X.H.; visualization, Y.D.; supervision, J.Y.; project administration, J.Y. and N.F.; funding acquisition, J.Y. All authors have read and agreed to the published version of the manuscript.  
This research was funded by National Natural Science Foundation of China (No. 52002009). Beijing Natural Science Foundation (No. 3222003), and the State Key Laboratory of Automotive Safety and Energy under Project No. KF2010.  
Not applicable.  
The data that support the findings of this study are available from the corresponding author upon reasonable request.  
The authors declare no conflicts of interest.