摘要
显式有限元方法是目前进行不同介质中炸药爆炸及爆轰波传播数值计算的主要方法。在此类研究中,通常需对爆源区设置高密度网格以捕捉爆炸过程中的高频成分。然而,对于大当量爆炸荷载作用下中远场地结构动力反应问题,即使在爆源-介质-目标整体模型中设置过渡网格,由于显式计算的时间步长受近爆源区域的最小网格尺寸控制,计算效率依然较低。鉴于此,提出一种基于爆源子结构的多尺度分析方法,该方法首先对近爆源区域自由波场进行分解,通过人工边界子结构的动力分析,将近爆源小尺度模型中的自由波场运动转化为大尺度模型中的等效爆炸荷载,从而完成爆炸问题的多尺度计算分析。提出的多尺度分析方法通过爆源子结构进行爆炸荷载的转化,避免了采用不规则形状单元的传统网格过渡方式,既降低了建模难度,又保证了计算精度,具有较强的实用性。此外,对于给定炸药当量的情况,通过该多尺度方法计算得到的等效爆炸荷载可作为标准荷载,在不同地下结构模型中重复使用,节省大量计算时间。通过均匀半空间自由场算例和成层半空间自由场算例验证了多尺度方法的可靠性。与整体模型方法相比,多尺度方法在保证计算精度的前提下,单元数量和计算耗时均大幅降低,计算效率优势明显。
The explicit finite element method is currently the main method for numerical calculation of explosion process and detonation wave propagation in different media.In such researches,high-density grids are usually generated to capture the high-frequency components throughout the simulation process.However,for the structural response analysis under the large equivalent explosion loads,even though the transitional mesh is set in the overall model of an explosive-medium-target system,the time step of the explicit algorithm is still controlled by the minimum grid size in the area near the explosion source,resulting in lower calculation efficiency.In this paper,a multi-scale analysis method based on the explosive source substructure was proposed.Through this method,the free wave field in the near-source area was decomposed.Then the free wave field motions in the small-scale model of the near-source area were transformed into the equivalent explosive loads in the large-scale model.Therefore the multi-scale analysis of the e explosion problem can be completed.The multi-scale analysis method proposed in this paper obtains the explosion loads through the explosion source substructure,avoiding the traditional mesh transition method with irregular-shaped elements,which not only reduces the difficulty of modeling,but also ensures the calculation accuracy,and has the advantage of strong practicality.In addition,for a given explosive equivalent,the equivalent explosive loads calculated by the multi-scale method can be applied as standard loads,which can be reused in different underground structure models,saving a lot of calculation time.The accuracy and practicability of the multi-scale method were verified by a homogeneous half-space free field example and a layered half-space free field example.Compared to the overall model method,under the premise of ensuring the calculation accuracy,the multi-scale method greatly reduces the number of element and the consuming time,without losing accuracy,leading to the obvious efficiency ad
作者
李述涛
宝鑫
刘晶波
陈叶青
LI Shutao;BAO Xin;LIU Jingbo;CHEN Yeqing(Department of Civil Engineering,Tsinghua University,Beijing 100084,China;Research Institute for National Defense Engineering of AMS,PLA,Beijing 100036,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2021年第20期63-72,共10页
Journal of Vibration and Shock
基金
国家重点研发计划(2018YFC1504305)
国家自然科学基金(51878384,U1839201)。
关键词
爆炸荷载
多尺度
爆源子结构
动力分析
人工边界
explosion load
multiscale
explosive source substructure
dynamic analysis
artificial boundary
