矢功率谱与RBF网络结合在旋转机械故障诊断中的应用

与传统功率谱相比,矢功率谱融合了多通道的能量信息,反映的信息更全面.径向基函数网络具有良好的推广能力和分类能力.基于此,本文结合矢功率谱和径向基函数网络,提出了一种新的故障识别方法,该方法以矢功率谱为特征向量,径向基函数网络为分类器.并以转子裂纹、转子不对中、油膜涡动为例进行实验研究,实验结果表明,该方法是有效的.     

国防生模拟连排建制管理的教育功能

依托普通高校培养军队干部是新时期我国国防建设的重大举措。本文针对普通高校如何完成该培养任务 ,在总结了中南大学国防生培养管理工作实践经验的基础上 ,提出了国防生模拟连排建制的管理模式 ,并对它的功能进行了具体分析。     

A STUDY OF B-P UNIFIED VISCOPLASTIC CONSTITUTIVE MODEL

By combining the Bodner-Partom constitutive model and equivalent stress function, finite element methods and program on analyzing non-elastic deformation and stress for thermal viscoplastic material are studied in this paper, and it's the first time that this material model is used in a kind of engineering software-MARC. Thermal viscoplastic behavior of high temperature alloy GH536 specimen with gap is analyzed by this program. The research results show it is feasible to analyze thermal viscoplastic behavior of specimen or structure by applying B-P model.     

Nanostructured component fabrication by electron beam-physical vapor deposition

Fabrication of cost-effective, nano-grained net-shaped components has brought considerable interest to Department of Defense, National Aeronautics and Space Administration, and Department of Energy. The objective of this paper is to demonstrate the versatility of electron beam-physical vapor deposition (EB-PVD) technology in engineering new nanostructured materials with controlled microstructure and microchemistry in the form of coatings and net-shaped components for many applications including the space, turbine, optical, biomedical, and auto industries. Coatings are often applied on components to extent their performance and life under severe environmental conditions including thermal, corrosion, wear, and oxidation. Performance and properties of the coatings depend upon their composition, microstructure, and deposition condition. Simultaneous co-evaporation of multiple ingots of different compositions in the high energy EB-PVD chamber has brought considerable interest in the architecture of functional graded coatings, nano-laminated coatings, and design of new structural materials that could not be produced economically by conventional methods. In addition, high evaporation and condensate rates allowed fabricating precision net-shaped components with nanograined microstructure for various applications. Using EB-PVD, nano-grained rhenium (Re) coatings and net-shaped components with tailored microstructure and properties were fabricated in the form of tubes, plates, and Re-coated spherical graphite cores. This paper will also present the results of various metallic and ceramic coatings including chromium, titanium carbide (TiC), titanium diboride (TiB₂), hafnium nitride (HfN), titanium-boron-carbonitride (TiBCN), and partially yttria stabilized zirconia (YSZ) TBC coatings deposited by EB-PVD for various applications. This paper was presented at the International Symposium on Manufacturing, Properties, and Applications of Nanocrystalline Materials sponsored by the ASM International Nanotechnology Task Force and TMS Powder Materials Committee, October 18–20, 2004, Columbus, OH.     

ANN valuation model of material LCIA profile

Weighting model is the only valuation model of life cycle impact assessment(LCIA) profile now. It simplifies evaluation function into linear function, and makes the determination of weighting factor complicated. Therefore the valuation of LCIA profile is the most critical and controversial step in life cycle assessment(LCA). Development on valuation models, which are understood easily and accepted widely, is urgently needed in the field of LCA.The modeling approaches for the linear evaluation function were summed up. The modeling approaches for the nonlinear evaluation function were set up by function approximation theory, which include choosing preference products, forming preference data, establishing artificial neural network(ANN) and training ANN by preference data.By selecting 7 material products as preference product, experience was done with modeling approaches of the nonlinear evaluation function. The results show that the modeling approaches and valuation model of the nonlinear evaluation function are more practical than the weighting model.     

点扩展函数与采样频率及量化精度对图像边缘的影响分析

文章在建立理想边缘成像模型的基础上,分析研究了一般成像系统的点扩展函数与空间采样频率的关系及对图像边缘定位精度的影响,给出了边缘定位误差.同时,还分析研究了量化精度对图像边缘的移位影响,给出了移位误差.最后,给出了本文的分析研究在零件视觉精密检测的应用情况.     

基于遗传算法的产品制造的优化调度

研究了企业产品制造的调度问题 ,并建立了调度的最小模型。引入效率函数 ,运用遗传退火进化算法实现了调度决策的优化 ;提出了将遗传退火算法和分派规则相结合的调度策略和动态编码的方法 ,放宽了约束条件 ,提高了搜索效率和速度 ,保证其全局收敛性。     

工序能力评价与经济分析

通过对工序能力的分析与评价 ,工序能力并非越高越好 ,提高工序能力有时意味着增加成本 ,故应作经济分析 ,本文介绍了一种经济分析的方法。     

1 250 mm五机架六辊冷连轧工艺控制系统核心技术

简要介绍了自主设计制造、具有完全自主知识产权的1 250 mm五机架六辊冷连轧产线工艺及设备特点。重点阐述了冷连轧工艺控制系统的硬件配置、软件架构及核心技术。采用基于简易有限元的轧制力模型及基于成本函数的多目标负荷分配模型，实现了高精度的轧制规程计算。开发了原料板快速启车技术与板形多变量综合最优控制技术，实现了冷轧产品的尺寸精准控制。现场实际应用效果表明，机组稳定运行率达到99.8%以上，不同规格的产品厚度控制精度均达到±0.8%以内，板形控制精度均达到5I以内。     

助卷辊电液伺服系统相关辨识法研究

用相关辨识法分析了卷取机助卷辊电液伺服系统的频率特性 ,采用 Levy法求出系统的传递函数 ,并且给出该系统频率特性相关参数。