空战仿真中平面机动方式的数学模型研究

本文研究空战机动方式的数学模型,给出了几个平面基本机动方式的数学模型及其详细指导。包括纯追踪、顺航向接敌、纯碰撞、正前置角接敌、负前置角接敌等。这些数字模型应用在一个平面双机格斗仿真专家系统中得到了良好的效果。     

核动力冷却剂主泵控制的模拟实践

冷却剂主泵是核动力装置系统中的重要设备之一,为模拟核动力系统,对冷却剂主泵切换控制采用电气模拟的方法。实践证明,这既节省经费,结构简单,同时逼真性好,工作性能可靠。     

飞行控制软件导航仿真模型遥测数据注入仿真

研究了飞行控制软件导航仿真模型遥测数据注入仿真中的一些问题,构造了遥测数据输入序列的误差补偿算法,重建相应的输入序列,使得将它们注入到相应的数字仿真模型进行仿真时,得到的输出与飞行试验中弹上计算机发送的遥测数据相符。     

XMSF下新兴开放标准的集成和验证

建模与仿真领域中实现资源重用、共享和互操作的基本途径是标准化。诸多开放互操作标准的提出和应用成功解决了各自领域的互操作问题,推动了仿真技术的发展。关于这些开放标准的讨论及应用情况都已有相当数量的文献予以介绍,但具体涉及同一框架下各标准之间相互作用或影响情况却鲜有提及。依托XMSF框架,选取了MDA、BOM、SRML、MSDL、C-BML五种主流的新兴开放标准,通过XMSF案例对这些标准在XMSF中的集成应用进行了详细研究,评估它们在一起时可能为仿真领域带来的影响和能力。     

考虑浮绳联结的双无人船艇系统协同控制策略研究

针对青岛等海域浒苔泛滥成灾的问题,开展了由浮绳柔性连接两艘水面无人船艇构成的双无人船艇系统协同控制策略研究,通过双无人船艇系统清扫浒苔,并将其拖运至海岸.考虑系统中的无人船艇动力、浮绳力矩和水流产生的干扰力矩,建立了欠驱动无人船艇三自由度动力学模型,提出了基于距离的包含编队和跟踪两个模式的协同控制策略.双无人船艇系统作...     

A study on the surface overpressure distribution and formation of a double curvature liner under a two-point initiation

The formation mechanism of an EFP(explosively formed projectile) using a double curvature liner under the overpressure effect generated by a regular oblique reflection was investigated in this paper.Based on the detonation wave propagation theory,the change of the incident angle of the detonation wave collision at different positions and the distribution area of the overpressure on the surface of the liner were calculated.Three-dimensional numerical simulations of the formation process of the EFP with tail as well as the ability to penetrate 45# steel were performed using LS-DYNA software,and the EFP ve-locity,the penetration ability,and the forming were assessed via experiments and x-ray photographs.The experimental results coincides with those of the simulations.Results indicate that the collision of the detonation wave was controlled to be a regular oblique reflection acting on the liner by setting the di-mensions of the unit charge and maintaining the pressure at the collision point region at more than 2.4 times the CJ detonation when the incident angle approached the critical angle.The distance from the liner midline to the boundary of the area within which the pressure ratio of the regular oblique reflection pressure to the CJ detonation pressure was greater than 2.5,2,and 1.5was approximately 0.66 mm,1.32 mm,and 3.3 mm,respectively.It is noted that pressure gradient caused the liner to turn inside out in the middle to form the head of the EFP and close the two tails of the EFP at approximately 120μs.The penetration depth of the EFP into a 45# steel target exceeded 30 mm,and there was radial expansion between the head and tail of the EFE increasing the penetration resistance of the EFP.Therefore,the structural size of the unit charge and the liner can be further optimized to reduce resistance to increase the penetration ability of the EFP.     

Numerical simulation of the natural fragmentation of explosively loaded thick walled cylinders

The ability to predict the natural fragmentation of an explosively loaded metal casing would represent a significant achievement. Physically-based material models permit the use of small scale laboratory tests to characterise and validate their parameters. The model can then be directly employed to understand and design the system of interest and identify the experiments required for validation of the predictions across a wide area of the performance space. This is fundamentally different to the use of phenomenologically based material algorithms which require a much wider range of characterisation and validation tests to be able to predict a reduced area of the performance space. Eulerians numerical simulation methods are used to describe the fragmentation of thick walled EN24 steel cylinders filled with PBXN-109 explosive. The methodology to characterise the constitutive response of the material using the physically based Armstrong–Zerilli constitutive model and the Goldthorpe path dependent fracture model is described, and the results are presented. The ability of an Eulerian hydrocode to describe the fragmentation process and reproduce the experimentally observed fragment mass and velocity distributions is presented and discussed. Finally the suitability of the current experimental analysis methodology for simulation validation is addressed.     

Numerical simulation of base flow with hot base bleed for two jet models

In order to improve the benefits of base bleed in base flow field, the base flow with hot base bleed for two jet models is studied. Two-dimensional axisymmetric Navier–Stokes equations are computed by using a finite volume scheme. The base flow of a cylinder afterbody with base bleed is simulated. The simulation results are validated with the experimental data, and the experimental results are well reproduced. On this basis, the base flow fields with base bleed for a circular jet model and an annulus jet model are investigated by selecting the injection temperature from 830 K to 2200 K. The results show that the base pressure of the annular jet model is higher than that of the circular jet model with the changes of the injection parameter and the injection temperature. For the circular jet model, the hot gases are concentrated in the vicinity of the base. For the annular jet model, the bleed gases flow into the shear layer directly so that the hot gases are concentrated in the shear layer. The latter temperature distribution is better for the increase of base pressure.     

A numerical study on the disturbance of explosive reactive armors to jet penetration

The disturbance of flat and V-shaped sandwich reactive armor configurations to shaped-charge jet is studied by a numerical approach. The disturbing and cutting effects of the two reactive armor configurations to the jet are successfully captured. The predicted disturbance characteristics and patterns are in fairly good agreement with the X-ray photographic observations. The residual depth of penetration into a semi-infinitive homogeneous steel target behind the reactive armor is computed for a series of jet/armor parameters. For the flat configuration, it is demonstrated that the residual penetration depth is not significantly reduced for a normal impact while it is reduced up to 75% for an oblique impact. In comparison, the V-shaped configuration reduces the penetration depth of the jet to 90%, and it is observed that the penetration depth is not sensitive to the V-shaped angle.     

舰船综合仿真标准体系探究

针对目前国内外仿真标准缺乏和零乱的现状对舰船综合仿真标准体系进行深入分析和研究,首先分析了国内外现状、我国舰船仿真领域的不足和仿真标准发展需求,接着对舰船综合仿真标准体系的技术思路、研究方法等做了初步性的探索,建立了舰船综合仿真技术参考模型,并据此初步建立了舰船综合仿真系统标准体系框架,用以指导制定具体的标准。