专家系统和多目标决策理论在抗沉决策系统中的应用

应用专家系统理论建立了抗沉规则库,确定了方案产生逻辑,同时运用多目标决策理论中的简单加性加权法建立了数学模型,对多方案抗沉效果进行了综合评估．成功地解决了舰艇生命力指标间的相互制约、相互影响的问题,为抗沉优化决策提供了新的思路和方法．     

Experimental investigation on anti-penetration performance of polyurea-coated ASTM1045 steel plate subjected to projectile impact

In this study, the anti-penetration performance of polyurea/ASTM1405-steel composite plate subjected to high velocity projectile was analyzed. Two kinds of modified polyurea material (AMMT-053 and AMMT-055) were selected and a ballistic impact testing system including speed measuring target system and high-speed camera was designed. This experiment was conducted with a rifle and 5.8 mm projectile to explore the effects by the polyurea coating thickness, the polyurea coating position and the glass-fiber cloth on the anti-penetration performance of polyurea/ASTM1405-steel composite plate. The result showed that the effects of polyurea coating position were different between two types of polyurea, and that the effects of glass-fiber position were disparate between two types of polyurea as well. For AMMT-053 polyurea material, it was better to be on front face than on rear face; whereas for AMMT-055 pol-yurea, it was better to be on rear surface although the difference was very subtle. Additionally, formulas had been given to describe the relationship between the effectiveness of polyurea and the thickness of polyurea coating. In general, AMMT-055 had better anti-penetration performance than AMMT-053. Furthermore, five typical damage modes including self-healing, crack, local bulge, spallation and local fragmentation were defined and the failure mechanism was analyzed with the results of SHPB test. Additionally, the bonding strength played an important role in the anti-penetration performance of polyurea/steel composite plate.     

装备战损等级评定方法研究

在对战场抢修力量部署进行思考的基础上,分析了战损等级评定影响因素,研究了兼顾装备损伤程度与战场抢修力量设置的战损等级评定方法。从而为装备战场抢修任务分工,以及对损伤装备的处理决断提供了依据,并为开展广泛深入的战损等级评定研究奠定了基础。     

基于专家系统的飞机致命性部件辨识方法研究

介绍了飞机致命性部件的辨识方法,尤其对该方法的核心部分,即损伤模式影响及致命性分析(DMECA)进行了详细的剖析。引用可靠性分析中比较成熟的FMECA(故障模式影响及致命性分析)思路来确定飞机的致命性部件,从而可为飞机易损性评估及战伤修复提供前提条件。通过考虑影响部件损伤率的因素(部件的尺寸大小、防护与遮挡、复杂程度等),借助系统综合评价中的关联矩阵方法,解决了DMECA分析表单中损伤率的来源问题,从而使DMECA方法切实可行。     

Research on the influences of confining pressure and strain rate on NEPE propellant: Experimental assessment and constitutive model

In order to study the influences of confining pressure and strain rate on the mechanical properties of the Nitrate Ester Plasticized Polyether (NEPE) propellant, uniaxial tensile tests were conducted using the self-made confining pressure system and material testing machine. The stress-strain responses of the NEPE propellant under different confining pressure conditions and strain rates were obtained and analyzed. The results show that confining pressure and strain rate have a remarkably influence on the mechanical responses of the NEPE propellant. As confining pressure increases (from 0 to 5.4 MPa), the maximum tensile stress and ultimate strain increase gradually. With the coupled effects of confining pressure and strain rate, the value of the maximum tensile stress and ultimate strain at 5.4 MPa and 0.0667 s⁻¹ is 2.03 times and 2.19 times of their values under 0 MPa and 0.00333 s⁻¹, respectively. Afterwards, the influence mechanism of confining pressure on the NEPE propellant was analyzed. Finally, based on the viscoelastic theory and continuous damage theory, a nonlinear constitutive model considering confining pressure and strain rate was developed. The damage was considered to be rate-dependent and pressure-dependent. The constitutive model was validated by comparing experimental data with predictions of the constitutive model. The whole maximum stress errors of the model predictions are lower than 4% and the corresponding strain errors are lower than 7%. The results show that confining pressure can suppress the damage initiation and evolution of the NEPE propellant and the nonlinear constitutive model can describe the mechanical responses of the NEPE propellant under various confining pressure conditions and strain rates. This research can lay a theoretical foundation for analyzing the structural integrity of propellant grain accurately under working pressure loading.     

Fatigue crack propagation in a helicopter component subjected to impact damage

Damage tolerant methodology is increasingly used in aeronautical components,especially due the fact that the Aviation Regulation requires such an assessment in case an accidental damage occurs.At pre-sent,there is a strong and actual interest in applying such procedures to helicopter components that are subjected to high frequency cyclic loads.In this paper,an investigation on a damaged transmission shaft for a tail rotor transmission of an actual helicopter has been carried out focusing on the fatigue crack propagation.A complete sequence of experimental tests was performed in order to create an actual ballistic damage and to subsequently check the damage tolerant behaviour.The shaft was damaged by oblique ballistic impact and was subsequently subjected to torsional fatigue loading.During the fatigue cycles several cracks propagated from the ballistic damages.Both of these steps(impact and fatigue loading)were also simulated by a complex modelling approach based on Finite Element Models and fracture mechanics theory.The comparison between the experimental and numerical results shows a good agreement but it underlines the need for a very refined modelling technique capable to replicate all the features associated with the damage in order to reliably simulate the subsequent propagation phase.     

用像素模拟仿真法计算子母弹头的毁伤效率

介绍了像素模拟仿真法的基本原理 ,给出了用该方法计算子母弹头对点、线、面目标毁伤效率的计算方法以及对典型目标机场跑道封锁效率的计算方法 ,并对实际工程中像素点的选取进行了研究 ;此外 ,提出了新颖的“探雷器”法 ,有效地解决了其它计算方法繁琐费时的弊端 ,从而大大提高了计算速度     

Damage to aircraft composite structures caused by directed energy system: A literature review

This paper presents a comprehensive review of the research studies on direct energy system effect on aircraft composite structures to develop a good understanding of state-of-the-art research and devel-opment in this area. The review begins with the application of composite materials in the aircraft structures and highlights their particular areas of application and limitations. An overview of directed energy system is given. Some of the commonly used systems in this category are discussed and the working principles of laser energy systems are described. The experimental and numerical studies re-ported regarding the aircraft composite structures subject to the effect of directed energy systems, especially the laser systems are reviewed in detail. In particularly, the general effects of laser systems and the relevant damage mechanisms against the composite structures are reported. The review draws attention to the recent research and findings in this field and is expected to guide engineers/researchers in future theoretical, numerical, and experimental studies.     

面向提高分析效率的战场损伤分析（FMEA／DMEA）方法研究

战场损伤分析是战场抢修研究、准备和决策的基础。从装备战场损伤分析出发,针对目前战场损伤分析(FMEA/DMEA)中存在的过程复杂、内容较多和效率不高等问题,探讨了如何利用基础性损伤数据和已有分析案例为FMEA/DMEA提供数据支持,提高分析效率。     

拦截TBM发射区的确定方法初探

在讨论拦截TBM杀伤区的基础上 ,应用TBM的运动方程 ,给出了确定低层反导防御系统拦截TBM时发射区的方法 ,对研究反导防御作战理论有一定的参考作用 ,同时 ,为指挥员选择最佳发射时机和发射方式提供了重要的理论依据。