Abstract Following the development of human economical activity, people have been gathering in the urban area. People¡¦s needs for space, environment, safety, convenience are increasing. People request not only just arrival at destination, but also a more comfortable, safer, more environment protection, more humanized transportation. So, for that reason, rolling stock transportation is becoming more and more important, and how to develop a comfortable, safe, environment - protective, humanized rolling stock is a very important issue today. Taiwan rolling stock market is very restrictive because it is close and small. Few people have studied in this field. For the coming 10 years, the situation will be changed because of the High Speed Railway system, Light Rail Track system, and Metro system. TRA Commuter system are flourishing. Also the government supports the Industrial Cooperation Program. In the Paper, I introduce the TQM concept from some Master such as Deming, Bill Creech, Crosby, Takuchi, and some TQM prize criteria, setting up a researching structure following the Bill Creech ¡§ Five Pillars of TQM¡¨, taking Saaty AHP (Analytical Hierachy Program) as a tool, consulting the expert of the rolling stock, seeking the priority of major factor of rolling stock researching quality management system.

Abstract Using a finite element package software DEFORMTM, this study simulated plastic deformation of the sheet at the roll-gap during sheet rolling processes. Rigid-plastic model of material is adopted. The rolls are assumed to be perfectly rigid and the sheets are isotropic. This study consists of three parts¡G(1) analysis of asymmetrical sheet rolling ; the effects of rolls speed ratios, roll radii ratios, friction factor ratios between sheet and rolls surface, upon the curvature of the rolled product and rolling force were systematically discussed. The larger the roll radius and the roll speed ratios are, the smaller the rolling force is and the larger the curvature of the sheet analytically. (2) Closing behavior, the deformation mechanism and stress-strain distributions around internal voids inside the sheet during sheet rolling was discussed numerically. The influences of various rolling conditions, such as the thickness reduction, the dimension of the internal void, friction factor, cross-sectional area of the void, etc., on the dimension of the void at the exit were discussed. The critical thickness reductions, over which the void would close completely, were also investigated. It is known that the critical reduction decreases with increasing roll radius. That is because the rolling pressure at the roll gap increases with increasing roll radius, accordingly, it takes smaller reductions to make the void closed completely. The critical thickness reduction decreases with increasing roll radius and decreasing voids dimension-thickness ratios. (3) The possibility of voids occurred at the front and back of the inclusion was investigated. The effects of various rolling conditions, such as the thickness reduction, the diameter of the inclusions, the roll diameter, friction factor, etc., on the generation and development of voids anticipated to occur in the front and rear of the inclusions were discussed. The critical thickness reductions under which void generation can be avoided were also examined. On the other hand, the effect of friction factor on between roll and sheet upon the void lengths in the front and rear of the inclusion is greater than that of friction factor on between inclusions and sheet. It is known that it decreases with increasing inclusions dimension, whereas the critical reduction decreases with decreasing roll radius. The analytical results showed a steady trend for 0.1mm< voids and inclusions dimension < 2.5mm. To verify the validity of the models, a series of experiments on the sheet rolling using aluminum (A1050, A6061) sheet as specimen were carried out. The experiments on sheet rolling with an internal void inside the sheet were conducted by micro-drill. The inclusions used ¡§SUS HSS¡¨ steel. The void length in the front of the inclusion is larger than that in the rear of the inclusion for both simulated and experimental results. The simulated results were compared with experimental results, and good agreement is found. Therefore, this numerical model using DEFORM software can offer useful knowledge for designing the pass-schedule in sheet rolling processes.

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<p>A general approach to numerically simulating wear in rollingand sliding contacts is presented in this thesis. A simulationscheme is developed that calculates the wear at a detailedlevel. The removal of material follows Archard’s wear law,which states that the reduction of volume is linearlyproportional to the sliding distance, the normal load and thewear coefficient. The target application is the wheel-railcontact.</p><p>Careful attention is paid to stress properties in the normaldirection of the contact. A Winkler method is used to calculatethe normal pressure. The model is calibrated either withresults from Finite Element simulations (which can include aplastic material model) or a linear-elastic contact model. Thetangential tractions and the sliding distances are calculatedusing a method that incorporates the effect of rigid bodymotion and tangential deformations in the contact zone.Kalker’s Fastsim code is used to validate the tangentialcalculation method. Results of three different sorts ofexperiments (full-scale, pin-on-disc and disc-on-disc) wereused to establish the wear and friction coefficients underdifferent operating conditions.</p><p>The experimental results show that the sliding velocity andcontact pressure in the contact situation strongly influencethe wear coefficient. For the disc-on-disc simulation, therewas good agreement between experimental results and thesimulation in terms of wear and rolling friction underdifferent operating conditions. Good agreement was alsoobtained in regard to form change of the rollers. In thefull-scale simulations, a two-point contact was analysed wherethe differences between the contacts on rail-head to wheeltread and rail edge to wheel flange can be attributed primarilyto the relative velocity differences in regard to bothmagnitude and direction. Good qualitative agreement was foundbetween the simulated wear rate and the full-scale test resultsat different contact conditions.</p><p><b>Keywords:</b>railway rail, disc-on-disc, pin-on-disc,Archard, wear simulation, Winkler, rolling, sliding</p>

published_or_final_version / Industrial Engineering / Master / Master of Philosophy

In this research, the effects of gas composition, elapsed time of reaction and temperature on scale formation and descaling of low carbon steel were investigated and results were discussed from the viewpoint of the phase composition of the scales, oxidation rates, oxidation mechanisms, adhesion, fracture mechanics, porosity and residual scale. / The phase composition and morphology of scales grown under conditions similar to those of reheating furnaces were analyzed. Low carbon steel was oxidized over the temperature range 1000-1250&deg;C in gas mixtures of O 2-CO2-H2O-N2, O2-H 2O-N2 and O2-CO2-N2. The mole fraction of each phase, wustite (FeO), magnetite (Fe3O 4) and hematite (Fe2O3) was determined by the direct comparison method Two types of scales were observed. The first type was a crystalline scale with an irregular outer surface composed mostly of wustite, and a negligible amount of magnetite. The second type was the classical three-layer scale composed of wustite, magnetite and hematite. In general, the experiments showed that the furnace atmosphere, oxidation time and temperature influence the phase composition of the scales. / Low carbon steel was oxidized in air over the temperature range 600-1200&deg;C for 120 s to approximate the formation of secondary and tertiary scale in hot rolling. The mole fraction of wustite, magnetite and hematite was determined by the direct comparison method The phase composition of the scales changed with temperature and time. During the initial 30 s of oxidation, wustite was the predominant phase in the temperature range 800-1200&deg;C, and as oxidation proceeded, the percentages of magnetite and hematite increased. In addition, the texture of the scales was investigated by orientation imaging microscopy (OIM); it was found that temperature influences the texture of the scales. The experiments indicated that 850&deg;C is the ideal temperature for the finishing mill in order to reduce surface defects and work roll wear. / The adhesion of scales formed in air on low carbon steel in continuous heating and isothermal conditions was investigated with a four-point bending test. The separation (crack) always occurred inside the scale indicating that the strength of the scale is lower than the strength of the scale/steel interface. It was found that scale adhesion is related to scale porosity, blister formation and stresses acting in the scale. A spallation process was observed when cooling from 800&deg;C to room temperature. The microscopic observations revealed that spallation followed route 1 "strong interface and weak oxide." / Low carbon steel was oxidized over the temperature range 1050-1250&deg;C in O2-CO2H2O-N2 gas mixtures in order to study the hydraulic descaling process. The oxidation times were 15-120 min. and the scales were 130-2000 mum thick. The experimental parameters were chosen to approximate scale formation under conditions similar to those of reheating furnaces. In the hydraulic descaling tests, two modes of scale removal were observed. In the first mode, observed in classical three-layer scales that developed an inner porous layer with low or medium porosity, the horizontal undercutting occurred at the boundary of the inner porous layer and dense scale. The second mode was observed in classical three-layer scales that developed an inner porous layer with high porosity and in crystalline scales. In the second mode, the horizontal undercutting occurred at the first plane of large pores relative to the scale/steel interface. In general, the experiments showed that scale morphology controlled the removability of scale.

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No description available.

Wheelchair manufacturers design their products to provide the best possible experience to their users. The user effort and wheelchair mechanical efficiency during motion are highly affected by rolling resistance, which is a resistive force depending on many factors such as vehicle speed, tire/floor materials and tire inflation pressure. The study of this force over several conditions could lead to improvements in wheelchair design. The Anatomical Model Propulsion System (AMPS) is a robotic device to test manual wheelchairs with better repeatability than human subjects, helping to identify the effect of resistive forces. It uses electric motors to apply torque directly to the rear wheel handrims. In this thesis, a control system is developed to achieve a specified wheelchair trajectory and velocity profile, by controlling the input torque to the system. A kinetic and dynamic model is used to estimate this necessary input. Data collected from different experiments allows to determine rolling resistance under various conditions. The results show that rolling resistance also varies with acceleration, affecting the overall mechanical efficiency of a wheelchair following different velocity profiles.

Heavy vehicles require tires which can withstand extreme loads while maintaining control, delivering performance and minimizing fuel consumption, particularly on soft soils. Recent advances in finite element analysis and computational efficiency have opened doors to highperformance, highly complex simulations which were not possible just a few years ago. This research aims to model two tires using non-linear finite element analysis code and validate them using static and dynamic tests, including response to steering input. Soils are modeled using both traditionally-meshed FEA techniques as well as a newer mesh-less smoothed particle hydrodynamics method. Soils are validated and the accuracy of the SPH and FEA models are compared. The tires and soils are used together to estimate the rolling resistance of the tire over various terrains. The developed soil models are sufficient to model soils behaving like clay. The SPH soil models behave closer to actual soils, providing superior penetration and shear properties. This causes the SPH soil models to exhibit rolling resistance closer to experimental data.