A Digital Perspective and the Quest for Substrate-Universal Behaviors

Should the Digital Perspective essays collected in these proceedings be viewed more seriously than attempts to play “fundamental theory”—which even in the hands of an Eddington was hard to tell from mythology and numerology? We argue that a nonfrivolous aspect of this Digital Perspective is its heuristic capacity: to help us guess which aspects of our understanding of nature are more “universal,” more robust, more likely to survive theoretical and experimental challenges. Behaviors that are substrate-independent—that can, for instance, thrive well on a digital support, even though they are traditionally imagined as taking place in a continuum—are especially promising candidates.     

粘弹性地基钢板爆炸焊接的计算模型

提出了一个钢坯爆炸焊接的计算模型。模型的数学表达式表明了振型函数、广义坐标及其频率与钢坯力学性能、土基力学性能和钢坯尺寸的具体关系。通过挠度的解析表达式,可获得这种爆炸加工的动态响应特性,为工程实践中优化参数和动态分析提供了有效工具。     

FAULT DIAGNOSIS OF ROTATING MACHINERY USING KNOWLEDGE-BASED FUZZY NEURAL NETWORK

A novel knowledge-based fuzzy neural network (KBFNN) for fault diagnosis is presented.Crude rules were extracted and the corresponding dependent factors and antecedent coverage factors were calculated firstly from the diagnostic sample based on rough sets theory.Then the number of rules was used to construct partially the structure of a fuzzy neural network and those factors were implemented as initial weights,with fuzzy output parameters being optimized by genetic algorithm.Such fuzzy neural network was called KBFNN.This KBFNN was utilized to identify typical faults of rotating machinery. Diagnostic results show that it has those merits of shorter training time and higher right diagnostic level compared to general fuzzy neural networks.     

空间机械的摩擦学设计探讨

本文对空间机械的摩擦学设计进行了探讨,指出要确保空间机械工作的可靠性,就应当根据摩擦学知识在进行空间机械摩擦副结构、强度及动力学设计的同时,合理地选择润滑方式和润滑材料。作者认为,系统地积累空间摩擦学基础知识和各类润滑材科的基本性能数据,以及建立材科的基本性能与实际应用性能之间的数学关系式,都是进行空间机械摩擦学设计所需要具备的条件,并且提出应当根据摩擦副的使用环境和操作条件选择润滑方式利润滑材料,以及根据润滑材科的性能确定摩擦副的结构、强度和动力学设计的摩擦学设计之方法与步骤。 作者在举例说明对空间机械进行摩擦学设计的重要性后强调指出,为了提高我国空间机械的设计水平,应当加强研究部门与设计部门的密切合作,加速建立以材料之基本性能为基础的摩擦学数据库,并逐步建立空间机械摩擦学设计方面的专家系统。     

水力机械转轮内的CFD分析及优化设计

本文基于Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程和标准的ｋ－ε紊流模型,模拟了转轮内的三维紊流场。同时,建立了一种现代水力机械转轮的设计方法;采用ＣＡＤ－ＣＦＤ系统,依据三维紊流场的预测结 果优化转轮内相关的几何参数,使得转轮内的流态接近理想流态,从而保证优化转轮的良好性能。     

竖向动载荷作用下平面框架结构水平动力响应分析

固定旋转机械引起的结构振动及其减、隔振控制是设备减、隔振领域一个十分重要的研究课题.以往的研究主要关注结构的竖向振动,而结构水平向振动往往被忽略.论文以设置有固定旋转设备的单层框架结构为例,分析了结构水平和竖向动位移幅值与结构固有频率、设备安装位置及设备运转频率之间的关系.研究结果表明,在特定条件下,结构水平向振动响应可能大于竖向振动响应,这一现象在设计时应引起足够的重视.     

Influence of Operating Parameters on Unbalance in Rotating Machinery Using Response Surface Method

Wide range of rotating machinery contains an inherent amount of unbalance which leads to increase in the vibration level and related faults. In this work, the effect of different operating conditions viz. the unbalanced weight, radius, speed and position of the rotor disc on the unbalance in rotating machine are studied experimentally and analyzed by using Response Surface Methodology (RSM). RSM is a technique which consists of mathematical and statistical methods to develop the relationship between the inputs and outputs of a system by distinct functions. L27 Orthogonal Array (OA) was developed by using Design of Experiments (DOE) according to which experimentation has been carried out. Three accelerometer sensors were mounted to record the vibration responses (accelerations) in radially vertical, horizontal and axial directions. The responses recorded as root mean square values are then analysed using RSM. The relationship between response and operating factors has been established by developing a second order, non-linear mathematical model. Analysis of variance (ANOVA) has been performed for verification of the developed mathematical models. Results obtained from the analysis show that the unbalance weight and speed are most significant operating conditions that contribute the most to the effect the unbalance has on the rotating spindle.     

农机配套服务的系统分析和协调优化模型研究

在界定农机配套服务的基础上,首先系统分析了农机配套服务的影响因素,以黑龙江垦区51个农场近10年农机和粮食产量等数据为例,采用相关分析、建立最优模型等方法知目前黑龙江垦区农机配套比与粮食单产相关系数的绝对值存在逐年减少趋势.再以七星农场近10年数据为例知小型农机具配套比与粮食产量相关性最密切,而利用建立最优回归模型揭示大中型拖拉机配套农机具对粮食产量起到显著作用.最后建立和分析农机配套服务的协调优化模型,确定了决策变量的满足条件,为推进农机配套服务具有重要意义.     

Fuzzy logic based automatic slip control system for agricultural tractors

In this study, a fuzzy-based automatic slip control system was developed for agricultural tractors. The developed system continuously measures the amount of slip that occurs during the tillage activities and automatically changes the operation depth of tillage equipment according to the amount of increase in the slip value. The amount of slip occurring on the driving wheels was applied as a separate input to the designed fuzzy control system (FCS) and at the fuzzy rule base, it was decided how much the depth of tillage would be reduced. The system was mounted on an agricultural tractor and trials were carried out in actual field conditions. The results of the tillage trials performed with the developed FCS were compared separately with the results of the tillage trials performed with an operator control (OC) without using any automatic control system. As a result of the trials, compared to the operator control, it was determined that in the tillage activities carried out with FCS, there were 42% decreases in slip values, 30% decreases in draft force values, 44% decreases in fuel consumption values and 5% increases in field work performance values. It was also observed that there were 10% changes in tillage depth.     

Electro-hydraulic tillage depth control system for rotary implements mounted on agricultural tractor Design and response experiments of control system

A tillage depth control system for rotary implements mounted on an agricultural tractor was designed and constructed to improve accuracy of tillage depth. The control system was composed of five main units: (1) a detecting unit to measure the tilting angle (position) of the lift arm, the pitching angle of the tractor and heights of sensors from ground surface, (2) a controlling unit, (3) a hydraulic unit to operate a three-point hitch linkage by a lift arm cylinder, (4) a three-point hitch linkage and rotary implements, and (5) a setting unit to put the reference tillage depth and a dead zone into the control circuit. The tillage depth was controlled by an on/off operation of a solenoid valve, of which time was proportional to the controlling time. Experiments to evaluate the response characteristics of the control system were conducted under various engine speeds, i.e. various flow rates of hydraulic oil, various tillage depths and some input frequencies. The results of the response experiments of the control system are discussed in this paper.