Effect of change of sand properties on travel distance of ricocheted debris  

作　　者：Yoon Keon Kim Woo Chun Choi 

机构地区：[1]Department of Mechanical Engineering,Korea University,145 Anam-ro,Seongbuk-gu,Seoul,02841,Republic of Korea

出　　处：《Defence Technology（防务技术）》2021年第4期1486-1495,共10页Defence Technology

基　　金：This study was financially supported by the Foundation Research Program[grant number UD170027GD]of the Agency for Defense Development and the Defense Acquisition Program Administration of the Republic of Korea.

摘　　要：The debris from exploded buildings can ricochet after colliding with the ground,thus increasing the debris travel distance and danger from any associated impacts or collisions.To reduce this danger,the travel distance of ricocheted debris must be accurately predicted.This study analyzed the change in the travel distance of ricocheted concrete debris relative to changes in the properties of a sand medium.Direct shear tests were conducted to measure the change in internal friction angle as a function of temperature and water content of the sand.Finite element analysis(FEA)was then applied to these variables to predict the speed and angle of the debris after ricochet.The FEA results were compared with results of low-speed ricochet experiments,which employed variable temperature and water content.The travel distance of the debris was calculated using MATLAB,via trajectory equations considering the drag coefficient.As the internal friction angle decreased,the shear stress decreased,leading to deeper penetration of the debris into the sand.As the loss of kinetic energy increased,the velocity and travel distance of the ricocheted debris decreased.Changes in the ricochet velocity and travel distance of the debris,according to changes in the internal friction angle,indicated that the debris was affected by the environment.

关 键 词：RICOCHET Exploded debirs Environmental change SAND Temperature Water content Internal friction angle Travel distance 

分 类 号：TJ410[兵器科学与技术—火炮、自动武器与弹药工程]