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柱形装药空中运动爆炸冲击波荷载计算模型

爆炸与冲击 2024年第7期44卷 105-123页

作者：王明涛程月华吴昊同济大学土木工程学院上海200092

为预测战斗部的爆炸威力,对柱形装药运动爆炸的入射和反射冲击波峰值超压和最大冲量开展数值仿真研究。首先,基于AUTODYN有限元分析程序提出了“三阶段”装药运动爆炸有限元分析方法,通过与已有静止和运动爆炸试验结果对比,验证了方法... 详细信息

为预测战斗部的爆炸威力,对柱形装药运动爆炸的入射和反射冲击波峰值超压和最大冲量开展数值仿真研究。首先,基于AUTODYN有限元分析程序提出了“三阶段”装药运动爆炸有限元分析方法,通过与已有静止和运动爆炸试验结果对比,验证了方法的可靠性。然后,考虑装药运动速度、长径比、比例距离、方位角和刚性反射等影响因素,开展了运动爆炸工况下200组柱形装药的数值模拟。结果表明:相较于静爆,动爆冲击波场整体前移,波阵面强度在装药运动方向增强而在反方向减弱,该影响与装药运动速度正相关。最后,针对柱形装药空中自由场运动爆炸和垂直于目标迎爆面运动爆炸的典型工况,分别提出了装药运动爆炸入射和反射冲击波峰值超压以及最大冲量的计算模型。该模型与2种战斗部柱形TNT装药运动爆炸工况的数值模拟结果符合良好,能较好地计算柱形装药空中运动爆炸冲击波荷载。

关键词：柱形装药空中运动爆炸峰值超压最大冲量计算模型

一种基于STL-Prophet-Informer模型的太阳电池阵多变量趋势预测方法

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空间控制技术与应用 2024年第1期50卷 35-45页

作者：张舒晗程月华姜斌南京航空航天大学自动化学院南京211100

为了提高太阳电池阵多变量预测的精度,解决阳电池阵遥测参数存在周期波动与增长性互相耦合的问题,提出一种基于STL-Prophet-Informer模型的太阳电池阵多变量预测算法.该算法首先应用局部加权周期趋势分解算法(seasonal and trend decomp... 详细信息

为了提高太阳电池阵多变量预测的精度,解决阳电池阵遥测参数存在周期波动与增长性互相耦合的问题,提出一种基于STL-Prophet-Informer模型的太阳电池阵多变量预测算法.该算法首先应用局部加权周期趋势分解算法(seasonal and trend decomposition procedure based on loess,STL)对太阳电池阵的多个参数分解为趋势分量、周期分量和残差分量,然后采用对趋势性数据预测效果较好的Prophet预测趋势分量,Informer模型预测周期分量和残差分量,最后将各分量预测结果相加后得到总的太阳电池阵参数预测值.以某卫星太阳电池阵实际遥测数据做算例分析,提出算法的各项误差评价指标和单一的Informer模型、LSTM模型等相比有明显减小,将该组合预测模型用于太阳电池阵多变量参数预测中,可以提高参数预测精度,提升卫星自主运行性能.

关键词：卫星遥测数据多变量预测 Informer网络局部加权周期趋势分解

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基于3D细观模型的混凝土动态压缩行为分析

爆炸与冲击 2024年第2期44卷 53-69页

作者：张湘茹程月华吴昊同济大学土木工程学院上海200092

通过建立混凝土的3D细观模型,在细观尺度上分析动态压缩荷载作用下混凝土材料内部裂缝的产生和发展、损伤演化和动态强度及其影响因素。首先,基于传统的“生成-投放”法生成粒径、形状和空间分布均随机的凸多面体粗骨料模型,并通过骨料... 详细信息

通过建立混凝土的3D细观模型,在细观尺度上分析动态压缩荷载作用下混凝土材料内部裂缝的产生和发展、损伤演化和动态强度及其影响因素。首先,基于传统的“生成-投放”法生成粒径、形状和空间分布均随机的凸多面体粗骨料模型,并通过骨料沉降和粒径缩放实现粗骨料的大体积率(达50%)和可调控;使用四面体网格划分骨料和砂浆表征其真实物理形状;使用界面粘结接触表征界面过渡区(ITZ)提升计算效率。进一步通过对比不同粗骨料粒径混凝土的分离式霍普金森压杆(SHPB)试验数据与模拟结果,如杆上应变时程、试件动态应力-应变曲线和试件损伤破坏模式,验证了建立的混凝土3D细观有限元模型、参数确定方法和数值仿真方法的准确性。最后,分析了30~100 s^(-1)应变率范围内骨料粒径(4~8、10~14和22~26 mm)、体积率(20%、30%和40%)和类型(石灰岩、花岗岩和玄武岩)对混凝土动态压缩强度的影响。结果表明:粗骨料粒径增大,混凝土动态压缩强度先增大后减小;粗骨料体积率越高,混凝土动态压缩强度越大;混凝土动态压缩强度随粗骨料强度的增加而提高。

关键词：混凝土 3D细观模型动态力学行为粘结接触应变率效应

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对地观测卫星姿态控制系统效能评估方法

北京航空航天大学学报 2024年第5期50卷 1655-1664页

作者：曹寅程月华高波张燕华徐贵力南京航空航天大学自动化学院南京211100 中国西安卫星测控中心西安710000

卫星系统效能评估问题,是卫星提高工作效率和卫星方案优化设计的基础。以对地观测卫星姿态控制系统作为效能评估的对象,通过对卫星的任务需求进行分析,建立对地观测卫星姿态控制系统效能评估指标体系;基于灰色关联分析相关理论,引入熵... 详细信息

卫星系统效能评估问题,是卫星提高工作效率和卫星方案优化设计的基础。以对地观测卫星姿态控制系统作为效能评估的对象,通过对卫星的任务需求进行分析,建立对地观测卫星姿态控制系统效能评估指标体系;基于灰色关联分析相关理论,引入熵权法计算指标权重,建立效能评估模型,计算得到综合灰色关联度,实现卫星姿态控制系统效能评估;通过数据验证所建体系具有可实现性与实用性。

关键词：卫星姿态控制系统效能评估灰色关联分析熵权法对地观测卫星

Perforation studies of concrete panel under high velocity projectile impact based on an improved dynamic constitutive model

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Defence Technology(防务技术) 2023年第9期27卷 64-82页

作者： Fei Zhou Hao Wu yuehua cheng Department of Disaster Mitigation for Structures College of Civil EngineeringTongji UniversityShanghai200092China

The finite-depth concrete panels have been widely applied in the protective structures,and its impact resistance and dynamic fracture failures,especially the scabbing/perforation limits,under high velocity projectile impact,are mainly concerned by protective engineers,which are numerically studied based on an improved dynamic concrete model in this ***,based on the framework of the KCC(Karagozian&Case concrete)model,a dynamic concrete model is proposed which considers an independent tensile damage model and a continued transition between dynamic tensile and compressive ***,the strength surface,equation of state and damage parameters of the proposed model are comprehensively calibrated by a triaxial compressive test with high confinement pressure,the rationality of which is further verified based on the single element tests,e.g.,uniaxial and triaxial compression as well as uniaxial,biaxial and triaxial ***,a series of projectile high velocity impact tests on thin and thick concrete panels are simulated,which indicates that the projectile residual velocity and dynamic fracture failures are reproduced satisfactorily,while the KCC model underestimates both the spalling and scabbing dimensions ***,based on the validated concrete model and finite element analyses approach,the validations of the existing five empirical formulae are evaluated,in terms of the depth of penetration(DOP)and scabbing/perforation limits of concrete *** the Army corps of engineers(ACE)and modified National Defense Research Committee(NDRC)formulae are recommended in the design of the protective structure to avoid scabbing failure.

关键词： Concrete panel Projectile Dynamic fracture Scabbing limit Constitutive model

Design and simulation of fault diagnosis based on NUIO/LMI for satellite attitude control systems

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Journal of Systems Engineering and Electronics 2012年第4期23卷 581-587页

作者： yuehua cheng Qian Hou Bin Jiang College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 R R. China Academy of Frontier Science Nanjing University of Aeronautics and Astronautics Nanjing 210016 P. R. China

This paper presents a scheme of fault diagnosis for flexible satellites during orbit maneuver. The main contribution of the paper is related to the design of the nonlinear input observer which can avoid false alarm arising from the disturbance from orbit control force. The effects of orbit control force on the fault diagnosis system for satellite attitude control systems, including the disturbing torque caused by the misalignments and the model uncertainty caused by the fuel consumed, are discussed, where standard Lu- enberger observer cannot work well. Then the nonlinear unknown input observer is proposed to decouple faults from disturbance, Besides, a linear matrix inequality approach is adopted to reduce the effect of nonlinear part and model uncertainties on the observer. The numerical and semi-physical simulation demonstrates the effectiveness of the proposed observer for the fault diagnosis system of the satellite during orbit maneuver.

关键词： orbit control flexible satellite attitude control system,nonlinear unknown input observer (NUIO) fault diagnosis.

Useful life prediction using a stochastic hybrid automata model for an ACS multi-gyro subsystem

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Journal of Systems Engineering and Electronics 2019年第1期30卷 154-166页

作者： cheng yuehua JIANG Liang JIANG Bin LU Ningyun College of Astronautics Engineering Nanjing University of Aeronautics and Astronautics College of Automation Engineering Nanjing University of Aeronautics and Astronautics

A useful life prediction method based on the integration of the stochastic hybrid automata(SHA) model and the frame of the dynamic fault tree(DFT) is proposed. The SHA model can incorporate the orbit environment, work modes, system configuration, dynamic probabilities and degeneration of components,as well as spacecraft dynamics and kinematics. By introducing the frame of DFT, the system is classified into several layers, and the problem of state combination explosion is artfully *** improved dynamic reliability model(DRM) based on the Nelson hypothesis is investigated to improve the defect of cumulative failure probability(CFP), which is used to address the failure probability of components in the SHA model. The simulation using the Monte-Carlo method is finally conducted on two satellites, which are deployed with the same multi-gyro subsystem but run on different orbits. The results show that the predicted useful life of the attitude control system(ACS) with consideration of abrupt failure,degradation, and running environment is quite different between the two satellites.

关键词： useful life prediction stochastic hybrid automata (SHA) multi-gyro subsystem dynamic fault tree (DFT) dynamic reliability.

Distributed fault diagnosis observer for multi-agent system against actuator and sensor faults

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Journal of Systems Engineering and Electronics 2023年第3期34卷 766-774页

作者： YE Zhengyu JIANG Bin cheng yuehua YU Ziquan YANG Yang College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Component failures can cause multi-agent system(MAS)performance degradation and even disasters,which provokes the demand of the fault diagnosis method.A distributed sliding mode observer-based fault diagnosis method for MAS is developed in presence of actuator and sensor ***,the actuator and sensor faults are extended to the system state,and the system is transformed into a descriptor system ***,a sliding mode-based distributed unknown input observer is proposed to estimate the extended ***,adaptive laws are introduced to adjust the observer ***,the effectiveness of the proposed method is demonstrated with numerical simulations.

关键词： multi-agent system(MAS) sensor fault actuator fault unknown input observer sliding mode fault diagnosis

A man-made object detection algorithm based on contour complexity evaluation

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Chinese Journal of Aeronautics 2017年第6期30卷 1931-1957页

作者： Guili XU Zhengbing WANG yuehua cheng Yupeng TIAN Chao ZHANG College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China College of Astronautics Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

Man-made object detection is of great significance in both military and civil areas, such as search-and-rescue missions at sea, traffic signs recognition during visual navigation, and targets location in a military strike. Contours of man-made objects usually consist of straight lines, corner points, and simple curves. Motivated by this observation, a man-made object detection method is proposed based on complexity evaluation of object contours. After salient contours which keep the crucial information of objects are accurately extracted using an improved mean-shift clustering algorithm, a novel approach is presented to evaluate the complexity of contours. By comparing the entropy values of contours before/after sampling and linear interpolation, it is easy to distinguish between man-made objects and natural ones according to the complexity of their *** results show that the presented method can effectively detect man-made objects when compared to the existing ones.

关键词： Complexity evaluation Contour chain code Contour detection Man-made object detection Salient contour