Structural-acoustic coupling characteristics of honeycomb sandwich plate based on parameter sensitivity analysis

The structural-acoustic coupling model for isotropic thin elastic plate was extended to honeycomb sandwich plate(HSP) by applying Green function method.Then an equivalent circuit model of the weakly-strongly coupled system was proposed.Based on that,the estimation formulae of the coupled eigenfrequency were derived.The accuracy of the theoretical predictions was checked against experimental data,with good agreement achieved.Finally,the effects of HSP design parameters on the system coupling degree,the acoustic cavity eigenfrequency,and sound pressure response were analyzed.The results show that mechanical and acoustical characteristics of HSP can be improved by increasing the thickness of face sheet and reducing the mass density of material.

Vibration properties and transverse shear characteristics of multibody molded beetle elytron plates

This study utilized cantilever experiments to investigate the vibration properties of multibody molded beetle elytron plates(BEPs),which is a type of biomimetic sandwich plate inspired by beetle elytra;the corresponding shear characteristics were further revealed by a finite element method(FEM). The following results were obtained:(1) Experimental results suggest that the maximum displacement response of the BEPs was about 25% less than that of a honeycomb plate with almost the same first natural frequency,which indicates that a BEP with reasonable structural parameters has the potential to replace a honeycomb plate to achieve better vibration performance;(2) The trabecular structure not only enhanced the shear stiffness of the core layer in column areas but also the skins in the honeycomb wall areas,thus changing the distribution of the shear force in the different components and improving the mechanical performances of the BEP;and(3) Although this enhancement effect from trabeculae was not uniform,the average shear force proportion of the skins(or core structure) in the entire BEP structure was very close to that of the honeycomb plate. Therefore,the shear calculation assumption used for honeycomb plates is still applicable in the BEP.The results provide an experimental basis for the design and application of BEPs and inspiration for the development of related products in vibrational environments.

The flexural property and its synergistic mechanism of multibody molded beetle elytron plates

To improve the applications of beetle elytron plates(BEPs,which are biomimetic sandwich plates inspired by beetle elytra),the flexural performance and its synergistic mechanism of multibody molded BEPs were investigated via cantilever testing and finite element method(FEM).The results are summarized as follows.(1)Although debonding damage causes failure of the multibody molded BEPs and honeycomb plate and the reasonable range of trabecular size for BEPs is narrow,both the optimal loading capacity per mass and failure deformation of the BEPs are over two times those of the honeycomb plate.(2)A flexural synergistic mechanism is revealed in the trabecular-honeycomb core structure of BEPs;this mechanism causes the maximum deformation of core structure to gradually transfer from the honeycomb wall to the trabeculae with the increase inη(the ratio of the trabecular radius to the distance between the center points of two trabeculae),which means the different stretching behaviors in these core structures.(3)Unlike the compressive mechanism of BEPs,by controlling and balancing the deformation degrees of the trabeculae and honeycomb walls,the flexural mechanism achieves a minimum core deformation and an optimal flexural performance.These results suggest a qualitative relationship between the deformation behavior of trabecular-honeycomb core structure and bending performance of the whole BEP,and provide a solid foundation for subsequent research and the considerable application potential of this biomimetic sandwich structure in many fields.

Influence Mechanism of the Trabecular and Chamfer Radii on the Three-point Bending Properties of Trabecular Beetle Elytron Plates

To improve the mechanical properties of Trabecular Beetle Elytron Plates(TBEPs,a type of biomimetic sandwich structure inspired by the beetle elytron)under transverse loads,three-point bending tests are performed to investigate the influence of the trabecular and chamfer radii of the core structure on the mechanical performance of TBEPs manufactured by 3D printing technology.The results show that the three-point bending performance of TBEPs can be improved by setting reasonable trabecular and chamfer radii;however,excessive increases in these radii can cause a decline in the mechanical performance.For the reason,these two structural parameters can enhance the deformation stiffness of the whole structure and the connection property between the core and skin,which is also the mechanical reason why Prosopocoilus inclinatus beetle elytra have thick,short trabeculae with a large chamfer radius.However,when these radii increase to a certain extent,the cracks are ultimately controlled between two adjacent trabeculae,and the failure of the plate is determined by the skin rather than the core structure.Therefore,this study suggests a reasonable range for trabecular and chamfer radii,and indicates that TBEPs are better suited for engineering applications that have high compression requirements and general bending requirements.