Predicting the Thermal Conductivity of AlSi/Polyester Abradable Coatings: Effects of the Numerical Method

The final target of this study is to achieve a better understanding of the behavior of thermally sprayed abradable seals such as AlSi/polyester composites. These coatings are used as seals between the static and the rotating parts in aero-engines. The machinability of the composite coatings during the friction of the blades depends on their mechanical and thermal effective properties. In order to predict these properties from micrographs, numerical studies were performed with different software packages such as OOF developed by NIST and TS2C developed at the UTBM. In 2008, differences were reported concerning predictions of effective thermal conductivities obtained with the two codes. In this article, a particular attention was paid to the mathematical formulation of the problem. In particular, results obtained with a finite difference method using a cell-centered approach or a nodal formulation allow explaining the discrepancies previously noticed. A comparison of the predictions of the computed effective thermal conductivities is thus proposed. This study is part of the NEWAC project, funded by the European Commission within the 6th RTD Framework programm (FP6).     

Manufacturing process modelling using process specification language

The manufacturing process is one of the important processes in a product??s life cycle. The sharing of manufacturing process information among different functional application systems, such as process planning, manufacturing simulation, manufacturing execution and project management, has become difficult to implement due to the growing complexity of the manufacturing information of product, process, resource and plant. A unified representation of manufacturing process information for all applications can enable convenient integration between different application systems. The development of manufacturing-related ontology and the Process Specification Language (PSL) has provided a formal definition and structure of semantic concepts for the capture and the exchange of manufacturing information. This paper presents a manufacturing process information modelling method which builds a standard, complete and exact definition of manufacturing process data by applying current PSL specifications. New extensions of the concepts of the manufacturing process and the types of relationship for describing activities, materials and resources in a process are identified and developed. The completeness and adaptability of activity relation of the proposed manufacturing process information representation is verified using mathematical induction under a variety of complex manufacturing process situations. The ability of the modelling method in expressing complex process information is demonstrated by a machining process example.     

车辆货物配装过程建模与优化决策

以家电企业配送为例研究车辆和多品种货物的配装问题。以配送中心车辆运力最大化为目标,研究如何对货物进行装车调配、优化处理来提高车辆的装载效率,以降低配送运输成本。对车辆类型、体积、载重额、客户优先级以及按区域配送线路等约束条件和目标函数进行系统分析,建立车辆货物配装数学模型。运用物流仿真软件建立货物配装的动态仿真模型,用遗传算法对配装过程进行优化,得出装载货物顺序编号的决策方案。仿真统计结果分析表明该仿真模型可以使顾客需求货物满足车辆容重约束并按优先级依次装车时的价值最大,车辆的载重量和有效容积利用率达到90%以上,降低了配送成本。     

液体粘性软启动控制精度影响因素的分析研究

针对液体粘性软启动试验重复精度差的问题,对影响控制精度的因素进行了分析,并提出了改进措施,改善了系统的控制精度。     

改进遗传算法求解柔性作业车间调度问题的研究

在考虑最大完工时间、总拖延时间、各个机器负荷平衡、所有机器上的总负荷等性能指标更加合理的情况下,设计一种新的选择算子,确保算法能快速收敛到全局最优解;利用提出的选择算子设计一种改进的遗传算法,提高求解效率.用基准实例测试改进的遗传算法,试验结果显示该算法能更有效地解决调度问题.     

原位分析仪检测钢中偏析分析影响因素的探讨

经过多次试验结合平时工作积累的经验,探讨了OPA-100金属原位分析仪应用过程中影响偏析分析结果准确性的因素,从仪器分析原理入手,主要研究了制样、描迹、工作曲线校正、保护气、扫描方向和区域的选择5个因素对分析结果的影响。     

一种基于啮合点的复杂轮系传动比计算方法

提出了一种基于啮合点的复杂轮系传动比快速计算方法.将复杂轮系分解为若干个轮系单元,根据“转化机构”法的基本原理,列出每个轮系单元的啮合方程,从而通过求解联立方程组计算出轮系传动比.分别讨论了定轴轮系、3K型周转轮系、2K-H型周转轮系及复杂轮系传动比的计算,并得出了定轴轮系和周转轮系之间的关系,把定轴轮系和周转轮系传动...     

基于光纤-镜面干涉腔的光纤加速度计

设计、研制了一种基于光纤-镜面干涉腔的光纤加速度计.介绍了该加速度计的传感原理及弹性结构设计,并对其性能进行了实验测试.该加速度计用固定于圆网状弹性结构上的硅微反射镜与处理过的光纤端面构成光纤-镜面干涉腔来产生相位差随外界加速度改变的光干涉信号;采用相位生成载波技术通过对干涉信号的调制和解调实现对相位差的精确测定.应用...     

Preparation and Interface Structures of Metal-encased SiC Composite Armors with Interpenetrating Structure

基于宏观有序多孔SiC陶瓷板的制备和对其进行金属铸造的复合技术制备了一种具有三明治互穿结构的新型金属封装SiC陶瓷复合装甲.采用SEM和EDS手段对3种复合装甲中金属(钢和钛合金)/陶瓷界面的显微结构和元素组成或分布进行了分析.相对优良的界面结合的获得与界面相互作用和铸造冷却过程中陶瓷主要受压应力的状态密切相关.界面结构取决于采用的金属材料(包括主体金属元素及其存在状态)和铸造工艺.     

抑制硬质合金中金属Co浸出的复合润滑剂研究

选用几种工业上常用的酸类润滑添加剂与三乙醇胺进行酯化反应生成不同润滑剂,将反应产物配成一定浓度的溶液对纯钴片和硬质合金刀具在常温下做浸泡实验,用纯钴片做电极与饱和甘汞电极组成原电池测定电动势,根据电动势的大小结合电镜扫描分析判断不同润滑剂溶液使金属Co浸出的情况,优选出抑制金属Co浸出效果好的润滑剂。实验结果表明:油酸三乙醇胺和油酸硼酸三乙醇胺对Co的浸出有抑制作用。