剪切增稠液体液舱侵彻实验

为研究剪切增稠液体(shear-thickening fluid, STF)液舱对弹体的防护性能，制备特定规格剪切增稠液体，并开展弹体侵彻剪切增稠液舱实验研究。实验中采用高速相机记录液舱侵彻过程中空泡的演化情况，并测试得到了弹体的剩余弹速以及前后靶板变形数据。实验结果显示，剪切增稠液体可有效抑制液舱侵彻过程中空泡的增长，从而降低液舱结构的损伤程度。结合空泡扩展理论模型，并考虑液体密度以及黏度变化对空泡增长的影响，验证了剪切增稠液体在高速冲击下产生的局部密度增大以及固化现象是抑制空泡扩展的主要原因。此外，剪切增稠液体对弹体速度的衰减作用明显，且相同初始弹速下，剪切增稠液体液舱前后靶板变形明显小于水体液舱。将剪切增稠液体填充于舰船液舱防护结构，可显著提高液舱结构的防护性能。

Experimental study on a cabin filled with shear-thickening fluid penetrated by projectiles

Experimental tests were designed to study the protection performance of the shear-thickening fluid (STF) cabin penetrated by projectiles. The penetration process and the development of cavitation in fluid cabins during the tests were captured by a high-speed camera. The residual velocities of the projectiles and the deformation of the front and rear targets of the fluid cabins were obtained as well. According to the cavitation images taken by the camera, the cavitation diameter of the STF was obviously smaller than that of water. Furthermore, cavitation collapse phenomenon was not found in the STF which shows that the STF has a significant effect in suppressing the evolution of cavitation during the penetration, and therefore decreasing the damage of the structure. A theoretical model for liquid cavitation evolution was used to find out the main factor in the cavitation suppression effect of the STF. On the one hand, the calculated cavitation diameters based on the theoretical model at two different densities were compared with the experimental results. The two densities are the densities of the STF and water, respectively, and the experimental cavitation diameters are much smaller than the calculated diameters, thus excluding the effect of density of liquid. On the other hand, the calculated cavitation diameter was also compared with the experimental data of common Newton liquid in the literature, and the effect of viscosity of liquid was excluded as well. Since both the density and viscosity may not be the main factor of the cavitation suppression effect of the STF, the assumption that the local density increase and curing effect of the STF particles attribute to the cavitation suppression was made. Besides, the STF also has a significant effect in the velocity attenuation of the projectiles and the deformation reduction of the targets. Hence, filling the STF into broadside liquid cabins of ships can significantly improve the protective performance of the structure.