人工制备冰雹的力学性能试验研究

The artificial hail can be used for ice collision test of various aviation accessories. Based on the ASTM F320-2010 standard, a variety of hailstones were designed and produced in this study. The mechanical properties of hailstones and the factors were investigated. A low-temperature universal testing machine was used to conduct quasi-static tests on hail. High-speed photography technology was adopted to analyze the hail crushing process and characteristics. The mechanical properties of hail under different cotton fiber types, cotton fiber characteristics, and cotton fiber content were analyzed. The results show that the cotton hail failure process can be divided into three stages: linear growth stage, yield stage, and crushing stage, with the maximum compressive strength during the failure process occurring at the end of the linear growth stage. The better the strength and elasticity of the cotton fiber, the larger the loading force required for hail breaking; the less the amount of ice attached to the cotton fiber, the smaller the loading force required for hail breaking. Increased cotton content can strengthen the connection of cotton fibers and increase the strength of cotton-containing hail; however, the hail compressive strength will not change much when the cotton content is larger than 15%. The compressive strength of hail made of hydrophilic cotton is significantly higher than that of hail containing hydrophobic cotton. The results of the study can provide reference for the verification of airworthiness compliance of civil aircraft in China.