基于分治的属性约简相对核计算

针对信息表中相对核的计算采用分治策略提出了一个新的属性约简方法,将在计算整个全域上的属性约简问题转化为计算在相应划分的子区域上属性约简问题.将原有计算POSX0(Y)的算法复杂度O(|A||U|2),降为O(|A|(|Y1|2+|Y2|2+…+|Yn|2)),对于一般比较大的|U|说,效率提高非常明显,提高了属性约简的可计算性.     

摩擦条件对纳米铜润滑添加剂减摩性能影响的研究

研究了摩擦速度、载荷和摩擦表面处理方式等摩擦条件,对纳米铜润滑添加剂减摩性能的影响,发现摩擦速度较高时,载荷增加使摩擦因数明显降低;在低载荷时摩擦速度的减小,使摩擦因数降低了17%,载荷增大后摩擦速度的变化,对摩擦因数的影响减小.摩擦表面抛光处理,使摩擦因数降低为磨削处理时的74%.     

装甲车辆工况监测参数的选择

为提高装甲车辆工况监测工作的规范性和可操作性,文章在对典型的履带式装甲车辆状态监测参数及技术性能检验方法的研究和分析的基础上,提出了在工况监测过程中,监测参数的选择方法和依据,并提出了典型的装甲车辆各机械系统工况参数。     

An efficient SPH methodology for modelling mechanical characteristics of particulate composites

Particulate composites are one of the widely used materials in producing numerous state-of-the-art components in biomedical, automobile, aerospace including defence technology. Variety of modelling techniques have been adopted in the past to model mechanical behaviour of particulate composites. Due to their favourable properties, particle-based methods provide a convenient platform to model failure or fracture of these composites. Smooth particle hydrodynamics (SPH) is one of such methods which demonstrate excellent potential for modelling failure or fracture of particulate composites in a Lagrangian setting. One of the major challenges in using SPH method for modelling composite materials depends on accurate and efficient way to treat interface and boundary conditions. In this paper, a master-slave method based multi-freedom constraints is proposed to impose essential boundary conditions and interfacial displacement constraints in modelling mechanical behaviour of composite materials using SPH method. The proposed methodology enforces the above constraints more accurately and requires only smaller condition number for system stiffness matrix than the procedures based on typical penalty function approach. A minimum cut-off value-based error criteria is employed to improve the compu-tational efficiency of the proposed methodology. In addition, the proposed method is further enhanced by adopting a modified numerical interpolation scheme along the boundary to increase the accuracy and computational efficiency. The numerical examples demonstrate that the proposed master-slave approach yields better accuracy in enforcing displacement constraints and requires approximately the same computational time as that of penalty method.     

Numerical simulation of warhead transportation

The new numerical approach for analysis of the warhead transportations is suggested.This approach allows to control the warhead operability before its experimental analysis.The approach is implemented by the adequate models for the software ANSYS.Analysis of the loads at land operations and trans-portations of the warhead by natural roads,water and aviation allows to obtain the maximal values of loads,which are used in numerical simulations of the warhead.These loads give an opportunity to analyze the operability and the fatigue strength of the cartridge warhead.The numerical simulations of the attachments of the warhead combat elements are performed on the basis of the suggested method.The data of the numerical simulations verifies the operability of the fastener system of the warhead combat elements.     

车载光学测量设备任务调度问题建模与求解

为提高观测方案效费比、改进探测能力,探索了一类车载光学测量设备的观测任务调度问题,并给出了解决方案。将观测任务调度问题建模为一个寻找最优观测方案的数学问题,结合设备的性能特点,给出了观测方案的数学描述,梳理了观测方案应满足的约束,提出了评价观测方案质量的指标,进而利用多属性决策方法来计算不同方案的总体效能,并排序获得最优方案。仿真算例验证了方法的有效性,相关研究成果对车载光学测量设备的运用实践具有一定的参考价值。     

基于动态神经网络的装备技术状态预测模型

装备的技术状态受多种因素的影响,诸多影响因素之间是一种多变量、强耦合、非线性的关系,同时这种关系还是动态的。根据装备技术状态的特性,使其在相空间里重构,然后利用动态神经网络建立装备技术状态预测模型,并以装备振动信号预测为例进行案例研究,验证了利用动态神经网络进行预测的可行性和优越性。     

喷水推进器功率特性与航速相关性研究

通过对某船喷水推进系统的分析,研究了喷水推进器的功率特性(功率与转速的关系)与航速的关系.先由喷水推进动力学方程引出喷水推进器功率特性在喷水推进系统稳态特性和动态性能研究中的作用,然后分析了KaMeWa71SⅡ喷水推进器的转速特性,将转速特性变换成力矩特性后,分析了该力矩特性,并将其与螺旋桨相应特性作了对比.根据转速特性获得的3个不同航速下的喷水推进器功率与转速的关系曲线,分析了航速对功率特性的影响,同时也将其与螺旋桨的相应特性曲线作了对比.研究所得出的结论是:喷水推进器的功率特性不是唯一的,装船之后它的功率特性受航速影响,但这个影响不像螺旋桨那么显著.据此推得,喷水推进系统在“船—泵—机”的匹配设计以及实际使用中,主机一般不会超负荷.     

基于LabVIEW的变速箱状态检测系统

采用门限关联度理论进行变速箱状态检测,并构建了以虚拟仪器为核心的变速箱状态采集系统,建立了表征变速箱状态的特征参量和正常故障判定准则,采用LabVIEW开发了检测与故障判定软件系统。     

刀具状态监测的模糊集方法

刀具状态监测技术一直是制约加工系统自动化和智能化水平提高的主要因素，本文采用模糊线性方程描述刀具状态与监测指标之间的关系，根据学习样本的可能分布和概率分布确定方程的参数，选用不同传感器信号特征组合进行对比实验，结果表明该方法可获得较高的识别率。