A deep understanding of explosive sensitivities and their factors is important for safe and reliable applications.However,quantitative prediction of the sensitivities is difficult.Here,reactive molecular dynamics simu...A deep understanding of explosive sensitivities and their factors is important for safe and reliable applications.However,quantitative prediction of the sensitivities is difficult.Here,reactive molecular dynamics simulation models for high-speed piston impacts on explosive supercells were established.Simulations were also performed to investigate shock-induced reactions of various high-energy explosives.The fraction of reacted explosive molecules in an initial supercell changed linearly with the propagation distance of the shock-wave front.The corresponding slope could be used as a reaction rate for a specific shock-loading velocity.Reaction rates that varied with the shock-loading pressure exhibited two-stage linearities with different slopes.The two inflection points corresponded to the initial and accelerated reactions,which respectively correlated to the thresholds of shock-induced ignition and detonation.Therefore,the ignition and detonation critical pressures could be determined.The sensitivity could then be a quantitative prediction of the critical pressure.The accuracies of the quantitative shock sensitivity predictions were verified by comparing the impact and shock sensitivities of common explosives and the characteristics of anisotropic shock-induced reactions.Molecular dynamics simulations quantitatively predict and rank shock sensitivities by using only crystal structures of the explosives.Overall,this method will enable the design and safe use of explosives.展开更多
研究了环面上非线性 van der Pol方程的图形建模及可视化计算的问题 .在图形环境下 ,对 van der Pol环面方程从建模、实验到结果分析的全过程进行了可视化建模和计算 ,并建立了一个对系统运动轨迹进行全面自动分析试验的可视化仿真框架 ...研究了环面上非线性 van der Pol方程的图形建模及可视化计算的问题 .在图形环境下 ,对 van der Pol环面方程从建模、实验到结果分析的全过程进行了可视化建模和计算 ,并建立了一个对系统运动轨迹进行全面自动分析试验的可视化仿真框架 .该方法不但可以不用传统程序代码对模型及算法编程 。展开更多
为了更直观、准确地表达和展示地震作用下城市燃气管网在实际地理环境中的空间关系及震害评估分析结果,基于VTK库、Adobe After Effects软件及Python语言提出了一种可全历程展示燃气管网在非一致地震激励下应变及破坏状态三维动态的可...为了更直观、准确地表达和展示地震作用下城市燃气管网在实际地理环境中的空间关系及震害评估分析结果,基于VTK库、Adobe After Effects软件及Python语言提出了一种可全历程展示燃气管网在非一致地震激励下应变及破坏状态三维动态的可视化模型方法。该方法包括3个模块:非一致地震激励下管网的基础数据提取及震害预测、三维可视化模型建立以及三维动态可视化模型建立。以西南某地区埋地燃气管网为例进行三维动态可视化模拟,立体直观展示该市管网在非一致地震激励下不同位置的应变响应及破坏情况,展示了该方法的三维动态可视化效果。展开更多
为研究长距离公路隧道电力电缆区在夏季机械通风条件下仍然存在的高温环境问题,以上海市G40长距离跨江隧道为研究对象,采用CFD模拟方法,探究电缆发热量、室外环境温度和通风量对电力电缆区温度场分布的影响规律,并提出适用于该隧道结构...为研究长距离公路隧道电力电缆区在夏季机械通风条件下仍然存在的高温环境问题,以上海市G40长距离跨江隧道为研究对象,采用CFD模拟方法,探究电缆发热量、室外环境温度和通风量对电力电缆区温度场分布的影响规律,并提出适用于该隧道结构的温度预测关联式,用于解决工程实践中面临的“高温区域覆盖范围如何界定”以及“下游温度超标临界条件如何判定”等关键问题。结果表明:1)在夏季机械排风工况下,电力电缆区的空气温度沿着隧道纵向呈现非线性增长趋势,表明气流驱动的热迁移现象显著;2)电缆发热量对隧道进排风温差呈现非线性增长特征,当电缆长期高负载运行时,电缆区排风温度将超过标准规定的安全阈值(≤40℃);3)降低隧道入口温度虽可减少排风温度,但会导致进排风温差扩大超出规范限值(≤10℃);4)通风量每增大87.81 m 3/s(即换气次数增大2次/h)可使排风温度降低约3.57℃,但过高的通风量会导致风机功耗激增,因此需要进一步研究通风策略以平衡降温效果与风机能耗之间的关系。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11832006).
文摘A deep understanding of explosive sensitivities and their factors is important for safe and reliable applications.However,quantitative prediction of the sensitivities is difficult.Here,reactive molecular dynamics simulation models for high-speed piston impacts on explosive supercells were established.Simulations were also performed to investigate shock-induced reactions of various high-energy explosives.The fraction of reacted explosive molecules in an initial supercell changed linearly with the propagation distance of the shock-wave front.The corresponding slope could be used as a reaction rate for a specific shock-loading velocity.Reaction rates that varied with the shock-loading pressure exhibited two-stage linearities with different slopes.The two inflection points corresponded to the initial and accelerated reactions,which respectively correlated to the thresholds of shock-induced ignition and detonation.Therefore,the ignition and detonation critical pressures could be determined.The sensitivity could then be a quantitative prediction of the critical pressure.The accuracies of the quantitative shock sensitivity predictions were verified by comparing the impact and shock sensitivities of common explosives and the characteristics of anisotropic shock-induced reactions.Molecular dynamics simulations quantitatively predict and rank shock sensitivities by using only crystal structures of the explosives.Overall,this method will enable the design and safe use of explosives.
文摘研究了环面上非线性 van der Pol方程的图形建模及可视化计算的问题 .在图形环境下 ,对 van der Pol环面方程从建模、实验到结果分析的全过程进行了可视化建模和计算 ,并建立了一个对系统运动轨迹进行全面自动分析试验的可视化仿真框架 .该方法不但可以不用传统程序代码对模型及算法编程 。
文摘为了更直观、准确地表达和展示地震作用下城市燃气管网在实际地理环境中的空间关系及震害评估分析结果,基于VTK库、Adobe After Effects软件及Python语言提出了一种可全历程展示燃气管网在非一致地震激励下应变及破坏状态三维动态的可视化模型方法。该方法包括3个模块:非一致地震激励下管网的基础数据提取及震害预测、三维可视化模型建立以及三维动态可视化模型建立。以西南某地区埋地燃气管网为例进行三维动态可视化模拟,立体直观展示该市管网在非一致地震激励下不同位置的应变响应及破坏情况,展示了该方法的三维动态可视化效果。
文摘为研究长距离公路隧道电力电缆区在夏季机械通风条件下仍然存在的高温环境问题,以上海市G40长距离跨江隧道为研究对象,采用CFD模拟方法,探究电缆发热量、室外环境温度和通风量对电力电缆区温度场分布的影响规律,并提出适用于该隧道结构的温度预测关联式,用于解决工程实践中面临的“高温区域覆盖范围如何界定”以及“下游温度超标临界条件如何判定”等关键问题。结果表明:1)在夏季机械排风工况下,电力电缆区的空气温度沿着隧道纵向呈现非线性增长趋势,表明气流驱动的热迁移现象显著;2)电缆发热量对隧道进排风温差呈现非线性增长特征,当电缆长期高负载运行时,电缆区排风温度将超过标准规定的安全阈值(≤40℃);3)降低隧道入口温度虽可减少排风温度,但会导致进排风温差扩大超出规范限值(≤10℃);4)通风量每增大87.81 m 3/s(即换气次数增大2次/h)可使排风温度降低约3.57℃,但过高的通风量会导致风机功耗激增,因此需要进一步研究通风策略以平衡降温效果与风机能耗之间的关系。
