摘要
近地小行星对地球的撞击是人类生存和发展面临的潜在威胁之一.当前小行星进入与撞击效应评估模型输入参数不确定度大,给模型的使用带来困扰,也较大地影响了危害评估结果.本文分析了输入参数的取值范围,以范围中概率最大或文献的推荐值作为敏感性研究的基准值,利用所发展的小行星进入与撞击效应分析评估软件AICA,通过改变一个或多个输入参数,研究能量沉积、空爆高度、4 psi(1 psi=6.89 kPa)超压损伤半径和3级烧伤半径等模型输出参数对输入参数的敏感性.对于直径60∼300 m、进入速度12∼40 km/s的石质小行星,本文的计算分析指出:随着尺寸的增大、进入速度的减小、烧蚀系数的减小、初次解体强度的增大或者碎片云质量分数的增大,小行星的空爆高度总体上减小;小行星及碎片阻力系数、强度指数对空爆高度和地面损伤范围影响较小;超压损伤半径和热辐射损伤半径总体上随着小行星尺寸和进入速度的增大而增大;碎片云质量分数小于50%时,能量沉积及地面损伤半径评估结果会出现波动,较大的碎片云质量分数基准值(如80%)能够代表大多数进入情况;流明效率仅影响热辐射损伤范围;3级烧伤半径小于4 psi超压损伤半径.
Asteroid impact on Earth is one of the potential threats to human beings.Engineering models of Earth entry and impact effects by asteroids have been developed in order to estimate ground hazard by planetary defense communities nowadays.However,there are large uncertainties in input parameters of these models,which not only brings trouble to use of the model,but also greatly affects results of hazard estimate.Ranges of input parameters are analyzed,of Which baseline values are taken as maximum probability values or recommended values in literatures.Furthermore,by changing one or more input parameters based on ranges and baseline values,AICA(Asteroid Impact Consequence Analysis)code developed by authors of this paper,are used to study sensitivity of output parameters,such as energy deposition,airburst altitude,radius of 4psi overpressure and 3rd degree burn,to input parameters.The results are given for stony asteroids with diameter of 60∼300 m and entry velocity of 12∼40 km/s.It is indicated by results that airburst altitude of asteroid trends to decrease,with increase of size,strength at 1st breakup and mass fraction of debris cloud,and with decrease of entry velocity and ablation coefficient.Drag coefficient of asteroid and fragment,as well as strength scaling exponent,has little effect on airburst altitude and ground damage range.Radius of overpressure and thermal radiation damage generally increases with increase of size and entry velocity.If mass fraction of debris cloud is less than 50%,airburst altitude and ground damage range will fluctuate.But a large value for mass fraction of debris cloud,such as 80%,is reasonable according to analysis of many meteor events at present.Luminous efficiency only affects damage range of thermal radiation.Under the computational condition in this paper,radius of 3rd degree burn is less than that of 4-psi overpressure,indicating that the main type of ground hazard is overpressure caused by airburst.
作者
党雷宁
柳森
白智勇
石义雷
Dang Leining;Liu Sen;Bai Zhiyong;Shi Yilei(Hypervelocity Aerodynamics Institute of China Aerodynamics Research and Development Center,Mianyang 621000,Sichuan,China)
出处
《力学学报》
EI
CAS
CSCD
北大核心
2021年第1期278-292,共15页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金资助项目(11972358).
关键词
小行星
进入与撞击效应评估模型
敏感性
超压
热辐射
asteroid
models of entry and impact effects
sensitivity
overpressure
thermal radiation