Investigation of Cutting Force by End Milling Operation

In this work, the cutting forces by end milling operation are analyzed. Therefore, the main parameters of cutting force as cutting speed, feed rate and depth of cut also are investigated in our case. The cutting force is modelled and analyzed into mathematical Wolfram simulations in order to compare the results and in the same time achieve the best solutions. Theoretical results are carried out by using the regression method that required fulfilling the critter by Fisher. The number of experiment, measurements and results of cutting force are presented in 2D as well as 3D. In order to verify the accuracy of the 2D diagram, the results for our case is used both two way such as experimental and theoretical method as well as results are compared. In other hands, these results indicate directly that the optimized parameters are capable of machining the workpiece. The obtained measurement results are compared with theoretical methods in Wolfram software.     

Shop-Floor Controller Based on RT-Middleware Technology

Nowadays the flexible configuration of manufacturing cells becomes to an important requirement especially at small and medium sized companies. This method can make the production fast and effective at small series or frequent manufacturing changes. The shop-floor control method, presented in this paper, offers a solution for the facing problem of fast and easy reconfiguration. The hardware of the controller designed modular with software components for online configuration. This solution allows sensor integration on different levels for every part of the manufacturing cell. With unified programming language and the machine specific controllers （post-processing） the cells can be defined easily by different types of human-machine interaction. The shop-floor control architecture is implemented and validated on an Adept SCARA （selective compliance assembly robot arm） robot. The robot is driven by standalone, low-level, interchangeable, software and hardware components.     

FE Study for Reducing Forming Forces and Flat End Areas of Cylindrical Shapes Obtained by the Roll-Bending Process

A roll-bending process that minimizes the flat areas on the leading and trailing ends of formed plates will produce more accurate and easier assemble final shapes. There are several methods of minimizing flat areas, but they are costly or difficult to apply for thick plates. This study proposes a new, simple approach that reduces these flat areas. This approach includes moving the bottom roll slightly along the feeding direction and adjusting the bottom roll location. Sensitivity analyses were performed using a developed 3D dynamic FE （finite element） model of an asymmetrical roll-bending process in the Ansys/LS-Dyna software package. Simulations were validated by experiments run on an instrumented roll-bending machine. The FE results indicate that this new approach not only minimizes the flat areas but also reduces the forming forces.     

H181成型磨床改进

本文介绍了活塞环H181成型磨床由液压进给改进方式为数控进给方式，包括：砂轮修整部分和磨削进给部分。     

混合遗传算法对BP神经网络算法的改进

介绍了用混合遗传算法对基本的BP神经网络算法进行改进的理论和实验,在混合遗传算法中使用了跨世代精英选择、退火算子以及自适应交叉和变异方法,取得了较好的效果。     

基于遗传算法和虚拟现实的施工设备布置系统

为辅助设计人员解决施工设备布置问题,基于遗传算法、虚拟现实技术和三维模型处理技术,提出了类交互式遗传算法。该算法首先执行计算机自动迭代完成的自然阶段,在满足人工参与条件后进入虚拟现实环境,进行人工评价和人工指导变异。通过对比分析表明,该算法能在明显减少用户参与次数的前提下,取得优于交互式遗传算法的解。基于该算法,实现了施工设备布置系统原型,并设计了基于不同技术的不同模块间的数据交互机制。实际应用验证了系统的有效性。     

基于最小完工期的离散型作业车间调度问题的遗传算法设计

针对离散型生产作业中的车间调度问题,以完工期最小为目标,设计了遗传算法,并利用PB语言编程实现该算法.最后,将该算法应用于某一钢铁公司金工车间的车间调度,并与原调度的结果做了比较,证明了本算法在实际应用中的有效性.     

基于最小完工期的离散型作业车间调度问题的遗传算法设计

针对离散型生产作业中的车间调度问题,以完工期最小为目标,设计了遗传算法,并利用PB语言编程实现该算法.最后,将该算法应用于某一钢铁公司金工车间的车间调度,并与原调度的结果做了比较,证明了本算法在实际应用中的有效性.     

Proof of Concept MFD Optimization of the Aftbody Geometry of Axisymmetric Slender Body Based on Wave Drag Considerations

A comprehensive, universally valid, elegant and yet simple method to design slender axisymmetric body of minimum wave drag in transonic and supersonic flows is developed. Computational aerodynamics is also used as a tool for numerical experiments in gaining physical understanding of the drag mechanism due to the geometry of the aftbody, such as the correlation between wave drag and wave distribution of the aftbody geometry. The method utilizes MFD （modified feasible direction） based optimization program, along with the linear slender body aerodynamics, for its elegance and generic optimization convenience. The efforts are focused on inviscid flow. A practical method of reducing the wave drag of a given body is developed for both bodies with pointed end and with base area, using shock wave generator at a particular location on the aftbody. The results show that the MFD optimization program can be effectively utilized in an aerodynamic optimization problem.     

Stabilizing Mechanism and Running Behavior of Couplers on Heavy Haul Trains

Published studies in regard to coupler systems have been mainly focused on the manufacturing process or coupler strength issues. With the ever increasing of tonnage and length of heavy haul trains, lateral in-train forces generated by longitudinal in-train forces and coupler rotations have become a more and more significant safety issue for heavy haul train operations. Derailments caused by excessive lateral in-train forces are frequently reported. This article studies two typical coupler systems used on heavy haul locomotives. Their structures and stabilizing mechanism are analyzed before the corresponding models are developed. Coupler systems models are featured by two distinct stabilizing mechanism models and draft gear models with hysteresis considered. A model set which consists of four locomotives and three coupler systems is developed to study the rotational behavior of different coupler systems and their implications for locomotive dynamics. Simulated results indicate that when the locomotives are equipped with the type B coupler system, locomotives can meet the dynamics standard on tangent tracks; while the dynamics performance on curved tracks is very poor. The maximum longitudinal in-train force for locomotives equipped with the type B coupler system is 2000 kN. Simulations revealed a distinct trend for the type A coupler system. Locomotive dynamics are poorer for the type A case when locomotives are running on tangent tracks, while the dynamics are better for the type A case when locomotives are running on curved tracks. Theoretical studies and simulations carried out in this article suggest that a combination of the two types of stabilizing mechanism can result in a good design which can significantly decrease the relevant derailments.     

RDG System in Remote Areas with Utility or Local Feed Topology and Operation Strategy

In remote regions with availability of wind energy, a RDG （renewable distributed generation） system is an advantageous alternative to increase the provision of electrical supply. Usually, these systems are structured on the basis of a connection to an existing weak grid. When the grid is out of service, the system may operate in islanding mode, if the RDG configuration allows it, continuing the provision of energy with standard voltage and frequency values. Facing the latter situation, a wind-diesel/gas generation system is proposed, with a conversion and control strategies based on a variable speed wind turbine employing a DFIG （doubly fed induction generator）, a SC （ultracapacitor） storage system and a SG （synchronous generator） driven by a diesel/gas engine.     

Identification Method of Dynamic Coefficients of Fluid Film Bearings for HDD Spindle Motors

Fluid film bearings are widely used as support elements of rotating shaft for HDD （hard disk drive） spindle motors. Recently, the opportunity for the HDD spindle motors exposed to external vibration has been increasing because the HDDs are used for various information related equipments such as mobile PCs, car navigation systems. Hence, the rotating shaft has a possibility to come in contact with the bearing and it causes wear or seizure to the bearing surface. In order to avoid the problems, it is extremely important to enhance the dynamic characteristics of the fluid film bearings for spindles. However, verification from both theory and experiment of dynamic characteristics such as spring coefficients and damping coefficients is rare and few. In this paper, the bearing vibration characteristics when the HDD spindle is oscillated are investigated theoretically and experimentally. And then the identification method ofoil film coefficients of fluid film bearing spindles is described.     

Composite with Recyclable Loads for the Manufacture of Blocks to Build Popular Houses

The science space in a state school in Natal city was built using a composite consisting of gypsum, EPS （expanded polystyrene）, shredded tire, cement and water. Mechanical and thermal resistances were evaluated. Inside the blocks, three types of fillings （EPS plates, aluminum cans and 500 mL bottles of mineral water） were placed in order to obtain a walls with higher thermal resistance, but also to give it an ecologically correct order, considering that both the tire and the EPS occupy a large space in landfills and require years to be degraded when released into the environment. Compression tests were conducted according to the rules. The experiments demonstrated that the temperature difference between the internal and external surfaces on the walls reached levels above 12.0 ℃. It was also demonstrated that the proposed composite has adequate mechanical strength to be used for sealing walls. The proposed use of the composite can contribute to reduce the significant housing deficit of Brazil, producing popular houses at low cost and with little time to work.     

Enhance Mining System Reliability through System Integration Approach

The reliability of mining systems is generally low due to their harsh working conditions. Currently, efforts for improving mining system reliability are often made in isolation. This practice could substantially limit the effectiveness of the efforts on overall reliability improvement of the mining system. To enhance the overall reliability of mining systems, an integrated improvement approach is necessary. In this paper, we developed a framework for integrated mining system reliability improvement to address this issue. In this framework, there are five major components including data integration, business process integration, hardware integration, software integration and analysis/decision integration, but we only focus on the integrated reliability analysis which is important to the analysis/decision integration. The reliability analysis considers the interactions between machines, and the impacts of design, operation, maintenance, automation and working environment on the overall system reliability. These multiple interactions present a big challenge to accurate reliability prediction. In this paper, we for the first time systematically investigated integrated reliability analysis approaches for dealing with this challenge using novel models and methods, including covariate hazard models, intelligent reliability prediction approach and complex system modeling methods. While these models and methods have found some successful applications in other industries, they in general have not been effectively used for the reliability analysis of mining systems. Our study results show that the system integration approach is applicable to mining systems and can be used for developing a computer aided integration system for the implementation of the integrated reliability improvement approach.     

Preliminary Study on the Seizure Trend of a MOM-THP with Self-directed Balls

This work continues the approach of one of our topics relating to a MOM-THP （metal on metal-total hip prostheses） with self-directed movement balls. Experiments revealed a certain seizure in some strain conditions. Laboratory trials for balls/plane Hertzian contacts have been restarted in order to determine seizure behaviour depending on the roughness of the flat area. The trials have been carried out in BSF （body simulated fluid） lubrication conditions, much closer to the real operating conditions up against the initial tests with distilled water. Seizure burdens to different loadings and contact surfaces roughness influence over the seizure burden have been determined. Even though the minimum value of the wear must be the same with the minimum value of the surfaces roughness, given the experimental conditions, it came out from the trials results on wear that the lowest level of wear is acquired at a certain value of roughness, not at the lowest level of roughness.     

Dynamic Detection of Reinforced Concrete Bridge Damage by Finite Element Model Updating

The present work consists of dynamic detection of damages in reinforced concrete bridges by using a MMUM （mathematical model updating method） from incomplete test data. A well suited finite element model of a repaired bridge is carried out. The diagnosis enables us to locate and detect the damage in a reinforced concrete bridge. Thus, developments of analytical predictions have been checked by modal testing techniques. Besides, the FTCS （finite time centered space） scheme is developed to solve the set of equations which can easily handle finite element matrices of a bridge model. It is shown in this study that the method is applied to detect damages as well as existing cracks in real time of a repaired bridge. To check the efficiency of the method, the repaired bridge of OuedOumazer in Algeria has been selected. It is proven that identification methods have been able to detect the exact location of damage areas to be corrected avoiding the inaccuracy from the finite element model for the mass, stiffness and loading.     

Investigation of CFD calculation method of a centrifugal pump with unshrouded impeller

Currently, relatively large errors are found in numerical results in some low-specific-speed centrifugal pumps with unshrouded impeller because the effect of clearances and holes are not accurately modeled. Establishing an accurate analytical model to improve performance prediction accuracy is therefore necessary. In this paper, a three-dimensional numerical simulation is conducted to predict the performance of a low-specific-speed centrifugal pump, and the modeling, numerical scheme, and turbulent selection methods are discussed. The pump performance is tested in a model pump test bench, and flow rate, head, power and efficiency of the pump are obtained. The effect of taking into consideration the back-out vane passage, clearance, and balance holes is analyzed by comparing it with experimental results, and the performance prediction methods are validated by experiments. The analysis results show that the pump performance can be accurately predicted by the improved method. Ignoring the back-out vane passage in the calculation model of unshrouded impeller is found to generate better numerical results. Further, the calculation model with the clearances and balance holes can obviously enhance the numerical accuracy. The application of disconnect interface can reduce meshing difficulty but increase the calculation error at the off-design operating point at the same time. Compared with the standard k-ε, renormalization group k-ε, and Spalart-Allmars models, the Realizable k-ε model demonstrates the fastest convergent speed and the highest precision for the unshrouded impeller flow simulation. The proposed modeling and numerical simulation methods can improve the performance prediction accuracy of the low-specific-speed centrifugal pumps, and the modeling method is especially suitable for the centrifugal pump with unshrouded impeller.     

Vibration Response Characteristics against the Radial and Axial Shocks on Small Size Hard Disk Drive Spindle Supported by Oil Film Bearings

This paper describes the experimental study on shock response of FDB （fluid dynamic bearing） spindle for HDDs （hard disk drives）. The FDBs are widely used as rotating shaft support elements for HDD spindle motors. Recently, the opportunity for the HDD spindle motors exposed to external vibration has been increasing because the HDDs are used for various information related equipment such as mobile PCs （personal computers）, video cameras, car navigation systems and so on. Hence, the rotating shaft has a possibility to come in contact with the bearing by external shocks and it causes wear or seizure to the bearing surface. To avoid the problem, it is extremely important to know how the spindle moves against the large shock on HDDs experimentally. However, as far as the authors know, there are few experimental studies treating the shock response of HDD spindles. In this paper, firstly, we propose a new test rig and experimental method for shock response of FDB spindles. Then the shock tests against the radial and axial disturbance on FDB spindle for 2.5＂ HDD are conducted. Finally, the experimental results of shock response waveforms and maximum displacement of disk are shown.     

Development of a Stabilized Pan/Tilt Platform and the State of the Art

In the context of this paper, a small scale, medium precision, stabilized pan/tilt platform is developed as a prototype, which is used to compare various stabilization algorithms experimentally. The overall performance of the system depends on rigid body dynamics, structural dynamics, servo control loops, stabilization control algorithm, sensor fusion algorithm and sensory feedback such as from the IMU （inertial measurement unit）. In the case that the response bandwidth of the overall system is high enough, the same hardware can also achieve active vibration isolation. All of these design aspects are investigated in the paper via numerical models and with their experimental verification.