新型星形负泊松比抗冲击结构设计与入水冲击

To solve the problem that the trans-media flight vehicle will be subjected to large impact load in the process of entering water, a topology optimization design method for anti-impact structure with of negative Poisson's ratio based on engineering requirements is proposed. A star-quadrangular honeycomb (SQH) structure with negative Poisson's ratio which meets the requirements of impact resistance is obtained by adding the elastic modulus and Poisson's ratio into the objective function of topology optimization design. Based on the theoretical analysis model of SQH structure, the analytical formula of plateau stress under impact load is deduced and verified by numerical simulation. Compared with the specific energy absorption of star-circle honeycomb (SCH) and other negative Poisson's ratio structures, the specific energy absorptions of SQH structure under low-speed, medium-speed and high-speed impact are 28. 74%, 45. 2% and 7. 03% higher than that of SCH structure, respectively. Through the fluid-solid coupling simulation analysis, the designed SQH sandwich structure is studied for load reduction by water- entry impact, and the influence of the main size parameters of SQH sandwich structure on the impact characteristics of water entry is further discussed. The results show that, within the allowable range of size, the increase in the inclination angle and wall thickness of SQH unit will reduce the peak acceleration of the structure and the transformation of kinetic energy into the deformation energy of the structure, which verifies the effectiveness of the negative Poisson's ratio structure topology optimization design for engineering requirements.