灰色层次分析方法在军用航空器需求论证中的应用

从军机的总体效能出发,综合考虑多种因素,建立起军机装备需求论证决策指标体系,运用灰色系统的相关理论和结合层次分析法,构建了基于灰色层次理论的新一代军机需求论证决策模型,通过实例计算表明这种模型的有效性和实用价值.     

基于灰色理论的飞机结构疲劳寿命预测

对飞机结构疲劳寿命进行预测研究,具有重要的军事意义与凸显的经济价值,本文以某型军用飞机关键结构部件——水平尾翼为具体研究对象,采用通过飞机结构疲劳寿命试验专用平台得到的水平尾翼疲劳寿命的真实试验数据,运用灰色相关理论建立非等间距GM（1,1）模型,应用此模型预测飞机结构部件的疲劳寿命,并通过试验对所建模型的准确性与有效性进行验证。试验表明,非等间距的GM（1,1）模型能准确地预测飞机结构部件的疲劳寿命,降低TOM（1,1）模型的预测误差,拓宽‘TGM（1,1）模型在飞机结构疲劳寿命预测领域的应用范围,具有很好的工程实用价值。     

航空救生系统实战效能评估

依据航空救生系统的战术技术指标,建立了航空救生系统的评价体系.运用灰色层次分析法和串并联系统理论,对ADC模型及其扩展模型进行修正,结合实例进行分析计算,给出了修正扩展模型下航空救生系统的效能,更有效地反映出救生系统的全面综合实战能力,给决策者提供可靠的理论依据.     

机载火警探测系统的改进研究

针对目前飞机货舱火警探测系统误报率高等问题,本文提出研究一种基于模糊信息融合理论的飞机货舱火警探测系统,同时利用温度传感器、一氧化碳传感器、红外烟雾传感器测试飞机货舱火警探测标的物,并将3种传感器所获得的温度、一氧化碳浓度、烟雾浓度参数信息进行模糊融合运算和决策处理,实现飞机货舱火警早期预报.验证结果表明,基于模糊信息...     

Spectral analysis of time-integrated Konus–Wind GRBs: Implication on radiative mechanisms

We have analysed a sample of 328 time-integrated GRB prompt emission spectra taken via the Konus instrument on board the US GGS-Wind spacecraft between 2002 and 2004 using a couple of two-components models, Cut-off Power Law (CPL) + Power Law (PL) and blackbody (BB) + PL. The spectra show clear deviation from the Band function. The PL term is interpreted as the low energy tail of a nonthermal emission mechanism. The distributions of corresponding index β give values β < −2/3 consistent with synchrotron and synchrotron self-Compton mechanisms. The distribution of low energy index α associated with the CPL term shows clear discordance with synchrotron models for 31.4% of the analysed GRBs with values exceeding that for the line of death, α = −2/3. Then, a set of nonthermal radiation mechanisms producing harder slopes, i.e., α > −2/3, are presented and discussed. For the remaining majority (68.6%) of GRBs with CPL index α < −2/3, we show that optically thin synchrotron produced by a power law electron distribution of type, N(γ) ∼ γ^−p, γ₁ < γ < γ₂, for finite energy range (γ₂ ≠ ∞) is a likely emission mechanism with α ∼−(p + 1)/2 in the frequency range ν₁ ? ν ? ν₂ (where ν₂ = η²ν₁ with η = γ₂/γ₁), such that for p > 1/3, one gets α < −2/3. We also show that corresponding spectra in terms of F_ν and νF_ν functions are peaked around frequency ν₂ instead of ν₁, respectively for p < 1 and p < 3. Besides, thermal emission is examined taking a single Planck function for fitting the low energy range. It can be interpreted as an early emission from the GRB fireball photosphere with observed mean temperature, kT′ ∼ 16.8 keV. Furthermore, we have performed a statistical comparison between the CPL + PL and BB + PL models finding comparable χ²-values for an important fraction of GRBs, which makes it difficult to distinguish which model and specific radiation mechanism (possible thermal or nonthermal γ-ray emissions) are best suitable for describing the reported data. Therefore, additional information for those bursts, such as γ-ray polarization, would be highly desirable in future determinations of GRBs observational data.     

Static Analysis of Functionally Graded Sandwich Plates Using an Efficient and Simple Refined Theory

In this paper, a new displacement based high-order shear deformation theory is introduced for the static response of function-ally graded sandwich plate. Unlike any other theory, the number of unknown functions involved is only four, as against five in case of other shear deformation theories. The theory presented is variationally consistent, has strong similarity with classical plate theory in many aspects, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. Two common types of functionally graded sandwich plates, namely, the sandwich with functionally graded facesheet and homogeneous core and the sandwich with homogeneous facesheet and functionally graded core, are considered. Governing equations are derived from the principle of virtual displacements. The closed-form solution of a simply supported rectangular plate subjected to sinu-soidal loading has been obtained by using the Navier method. The validity of the present theory is investigated by comparing some of the present results with those of the classical, the first-order and the other higher-order theories. It can be concluded that the proposed theory is accurate and simple in solving the static bending behavior of functionally graded sandwich plates.     

空间可展开结构区间模型修正方法

传统的模型修正未考虑工程中存在的几何尺寸、材料参数、间隙等不确定性,修正后有限元模型预测精度较低。为提高有限元模型的预测精度,准确预测结构的静动力学特性,对考虑参数不确定性的模型修正进行了研究,提出了一种基于Kriging模型和泛灰数的区间模型修正方法。首先,通过灵敏度分析确定待修正参数,并以修正参数为变量,构造基于Kriging模型的区间响应目标函数;其次,引入泛灰数将区间优化问题转换为区间上限和区间直径两个全局优化问题;然后,利用Kriging模型结合遗传算法给出修正后的参数区间形式;最后,通过该方法对含铰链间隙的某空间可展开结构进行了模型修正。结果表明,修正后参数区间与真实区间重合度较高,修正后结构响应预测区间与实际区间吻合,验证了方法的有效性,为大型空间可展开结构的模型修正提供了一个有效可行的途径。     

Mechanical study on initial profile solution for inflatable reflector made of orthotropic material

The woven fabric membrane materials are widely used in space and terrestrial inflatable reflectors. However the material?s anisotropy makes the design analysis more complex. The deviation from the desired shape, so-called “W-profile error”, influences the precision of the membrane surface significantly. In this study, a model of an axisymmetric paraboloid surface using membrane theory is established for the purpose of facilitating the surface precision optimization. Analytical solutions for displacements of the reflector are derived. An iteration method of initial reflector profile solution is stated and a finite element (FE) software employed in the solution is presented. A case study is illustrated to make a comparison between numerical and theoretical analyses. Finally, the conclusions are drawn that the analytical method and the FE iterative method for initial profile solution are feasible and efficient.     

存款保险制度的博弈分析

银行业在一国经济活动中具有特殊地位,银行破产将会给一国的经济发展造成很大的负面效应,有效防范和化解金融风险是一国金融体系稳定运行的重要保证。本文从博弈论的角度来分析存款保险制度的作用, 指出存款保险制度有利于银行业的稳定和系统性金融风险的化解。     

The gauge-generalized Gyldén–Meshcherskii Problem

The Gyldén–Meshcherskii Problem (GMP) extends the classical two-body problem of Newton and Kepler by considering time-varying gravitating masses, an important extension of the two-body problem for modeling cometary motion and cosmological phenomena. In this paper, we consider the GMP in a specialized setup, the setup of gauge theory. We show that the variational equations, modeling the effect of the mass time variation on the orbital elements, can be derived by fixing a gauge of a particular form that is different from the Lagrange gauge. Thus, the orbital elements modeling the effect of a time-varying secondary mass are non-osculating. This implies that the trajectory of a celestial body whose mass is continuously changing cannot be approximated by a series of Keplerian orbits. Finally, we provide the first-order averaged equations written in terms of non-osculating elements.