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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

High temperature, permanent magnet biased, homopolar magnetic bearing actuator

Hossain, Mohammad Ahsan 30 October 2006 (has links)
The EEC (Electron Energy Corporation) in conjunction with the National Aeronautics and Space Administration is researching the magnetic bearings for an alternative to conventional journal or ball bearings. The purpose of this research was to design and develop a high-temperature (1000ºF) hybrid Magnetic Bearing using High Temperature Permanent Magnets (HTPM), developed by the EEC for high performance jet engines at high speeds that supply loads of 500 lbf. Another objective is to design and build a test rig fixture to measure the load capacity of the designed bearing. The permanent magnet bias of the Homopolar radial magnetic bearing reduces the amount of current required for magnetic bearing operation. This reduces the power loss due to the coil current resistance and improves the system efficiency because the magnetic field of the HTPM can suspend the major portion of the static load on bearing. A high temperature radial magnetic bearing was designed via an iterative search employing 3D finite element based electromagnetic field simulations. The bearing was designed to produce 500 lbf of force at 1000ºF and the design weight is 48 lbs. The bias flux of the Homopolar radial bearing is produced by EEC HTPM to reduce the related ohmic losses of an electromagnetic circuit significantly. An experimental procedure was developed to measure actual load capacity of the designed bearing at the test rig. All the results obtained from the experiment were compiled and analyzed to determine the relation between bearing force, applied current and temperature.
22

Design and Implementation of a Test Rig for a Gyro Stabilized Camera System

Eklånge, Johannes January 2006 (has links)
PolyTech AB in Malmköping manufactures gyro stabilized camera systems or helicopter applications. In this Master´s Thesis a shaker test rig for vibration testing of these systems is designed, implemented and evaluated. The shaker is required to have an adjustable frequency and displacement and different shakers that meet these requirements are treated in a literature study. The shaker chosen in the test rig is based on a mechanical solution that is described in detail. Additionally all components used in the test rig are described and modelled. The test rig is identified and evaluated from different experiments carried out at PolyTech, where the major part of the identification is based on data collected from accelerometers. The test rig model is used to develop a controller that controls the frequency and the displacement of the shaker. A three-phase motor is used to control the frequency of the shaker and a linear actuator with a servo is used to control the displacement. The servo controller is designed using observer and state feedback techniques. Additionally, the mount in which the camera system is hanging is modelled and identified, where the identification method is based on nonlinear least squares (NLS) curve fitting technique.
23

High temperature, permanent magnet biased, homopolar magnetic bearing actuator

Hossain, Mohammad Ahsan 30 October 2006 (has links)
The EEC (Electron Energy Corporation) in conjunction with the National Aeronautics and Space Administration is researching the magnetic bearings for an alternative to conventional journal or ball bearings. The purpose of this research was to design and develop a high-temperature (1000ºF) hybrid Magnetic Bearing using High Temperature Permanent Magnets (HTPM), developed by the EEC for high performance jet engines at high speeds that supply loads of 500 lbf. Another objective is to design and build a test rig fixture to measure the load capacity of the designed bearing. The permanent magnet bias of the Homopolar radial magnetic bearing reduces the amount of current required for magnetic bearing operation. This reduces the power loss due to the coil current resistance and improves the system efficiency because the magnetic field of the HTPM can suspend the major portion of the static load on bearing. A high temperature radial magnetic bearing was designed via an iterative search employing 3D finite element based electromagnetic field simulations. The bearing was designed to produce 500 lbf of force at 1000ºF and the design weight is 48 lbs. The bias flux of the Homopolar radial bearing is produced by EEC HTPM to reduce the related ohmic losses of an electromagnetic circuit significantly. An experimental procedure was developed to measure actual load capacity of the designed bearing at the test rig. All the results obtained from the experiment were compiled and analyzed to determine the relation between bearing force, applied current and temperature.
24

Fuel injector spray diagnostic development

Slator, Duncan January 2015 (has links)
New technologies are constantly developing towards the goal of increasing the performance of gas turbine engines while reducing pollutant emissions. The design of the combustion system is vital in the drive to reduce pollutants in order to meet legislative targets. As part of this, the fuel injector is crucial in preparing the fuel for combustion through atomization and correct mixing with the air flow. Thus, it is desirable to develop techniques to allow the analysis of performance in these key criteria and improve the understanding of both fuel injector aerodynamics and fuel atomisation. Particle Image Velocimetry (PIV) allows for spatially resolved velocity data of flow fields to be recorded and therefore enables the inspection of flow behaviour.
25

Modelling of Test Bench for Road Load Simulation

Åberg Skender, Dennis January 2017 (has links)
Warehouse forklifts are often powered by batteries. By using a test bench where the forklift can be driven in a certain driving-cycle, the battery capacity can be tested. To obtain the same speed curve on the test bench as a forklift obtains when driving on a real road, the test bench must be able to simulate road load. In this master’s thesis, a test bench is modelled in Simulink using grey-box modelling and validated with measured data. Also, a speed regulator is developed and implemented in the test bench model to simulate road load. Simulations with the model and the speed regulator show high accuracy when compared against measured data. However, the results show that the pre-attached torque sensor is not optimally located, and that the gear oil temperature is of interest to measure to be able to model the friction torque as a function of the temperature. / Lagertruckar drivs ofta av batterier. Batterikapaciteten kan testas genom att använda en testbänk där trucken körs i en körcykel. För att simulera samma hastighetskurva på testbänken som trucken erhåller vid riktig körning på väg måste testbänken kunna simulera vägmotstånd. I detta examensarbete modelleras en testbänk i Simulink genom grey-box modellering och valideras med uppmätt data. Även en hastighetsregulator utvecklas och implementeras i modellen för att simulera vägmotstånd. Simuleringar med modellen och hastighetsregulatorn visar på hög träffsäkerhet jämfört med uppmätt data. Resultaten visar dock på att den monterade momentsensorn inte är optimalt belägen och att växeloljans temperatur är av intresse att mäta för att kunna modellera friktionen som en funktion av temperaturen.
26

Modelling and Analysis of a Screw Joint Test Rig

Fallsberg, Beatrice January 2017 (has links)
Today, tightening tools are widely used in the industry and on the market you will find several products that have been assembled with the help of tightening tools. For example, tightening tools are used in the automotive industry and when assembling computer hardware. It is important that the tightening tools are robust and of high quality in order to fulfil the demanded requirements. High assembly speed has entailed an extensive use of tightening tools. To ensure that the tightening tools have the desired properties, tightening tools are tested continuously using so-called test systems. This puts high demands on the test systems since it is of importance that the tightening tools can be tested in a simple, fast and reliable way as well as repeatedly. Therefore, Atlas Copco would like to investigate whether a test system constructed with an electrical motor is a good choice. The idea of this thesis is to investigate possibilities and limitations in a test system consisting of an electrical motor that emulates the behaviour of a screw joint. To be able to investigate hardware limitations a test rig is constructed and then modelled in MATLAB. Further, simulations have been carried out in order to analyse the possibilities and limitations of such a test rig. The conclusion is that the implemented LQ controller seems to be able to control the braking motor sufficiently like a screw joint.
27

Evaluating the repeatability of friction and wear testing on a lubricant with dispersed hexagonal-boron nitride nanoparticles

Benadé, Howard P. January 2015 (has links)
The SRV test rig was used to evaluate the friction and wear properties of a lubricant in a laboratory setup. Normally, the coefficient of friction and the amount of wear that occurred are measured while the wear scar surface is also evaluated. Special attention was paid to factors that affect the repeatability. The test fluid was subjected to a friction and wear test on the SRV test rig in order to determine what factors affect the repeatability of the coefficient of friction, the amount of wear that occurred and the wear scar appearance. The test fluid used was based on rapeseed oil and white mineral oil. The fluid also contained an extreme pressure additive in the form of sulphurised ester. This was also compared for the same test fluid with dispersed hexagonal-boron nitride (h-BN) nanoparticles. The standard test method as described by ASTM D 6425, was used as test method. Instead of the standard temperature, the block temperature was increased to 100 °C in order to simulate harsher operating environments. The load was set at 200 N It was found that:  The rapid load increase from 50 to 200 N at the end of the running-in period (as described in the standard test method) caused poor repeatability. The test was modified with a more gradual load application for the duration of the running-in period (30 N/min), which resulted in improvement in the repeatability of the tests conducted.  The moisture content in the atmosphere also affected the repeatability of the friction and wear tests. This was most likely due to the formation of a corrosion layer that involves water and by keeping the relative humidity constant, a further improvement in the repeatability was observed. The addition of the h-BN nanoparticles resulted in an improvement of the repeatability of the coefficient of friction (COF), wear scar surface (WSS) and wear scar volume (WSV), since the wear scar surfaces indicated that the particles remove the corrosion layers. This could have led to more consistent wear surfaces for the duration of the test.  The particles also influenced the corrosion layer formation. For both fluids, Raman spectroscopy indicated that greigite (Fe3S4) and goethite (α-FeOOH) were found on the surface, while additional corrosion products were found on the wear scar surface for the test fluid with dispersed particles. These compounds were melanterite (FeSO4.7H2O) and rozenite (FeSO4.4H2O). All these corrosion products were most likely formed due to the reaction of iron from the specimens with sulphurised esters in the test fluid. / Dissertation (MEng)--University of Pretoria, 2015. / tm2015 / Chemical Engineering / MEng / Unrestricted
28

Návrh stavu pro dlouhodobé testování pryžových segmentů / Test Rig Design for Durability Testing of the Rubber Segments

Borek, Vojtěch January 2019 (has links)
The aim of diploma thesis is construction design of test rig for durability testing of the rubber segments. The work contains a brief description of tested component, test rigs and individual parts of the testing system. Next chapter describes conception and construction solutions with justification of choice specific parts, supported by analysis of critical parts. Finally the overall construction design is evaluated and accompanied with a documentation of drawings, which is attached to the thesis.
29

Rekonstrukce stanice AXMAT / Reconstruction of AXMAT Testing Station

Gergel, Matej January 2014 (has links)
The master´s thesis deals with reconstruction of RCF test rig AXMAT. Main goal is design new hydraulic load system and his realization. The first part of thesis describes similar experimental machines and their pros and cons. This analysis is base for complete reconstruciton of AXMAT. New hydraulic load system allows dynamic programmable load cycles. Control system with close loop and feedback was created in software Matlab – Simulink. Main frame was reconstructed too. Control and action parts were asseble to station. Output of thesis is function sample.
30

Dirt Ingress Behavior of Wipers for Hydraulic Cylinders

Barillas, Gonzalo A., Richter, Sören, Weber, Jürgen January 2016 (has links)
Dirt ingress in hydraulic cylinders is one of the sources that leads to pollution of hydraulic systems. There are already several test rigs to investigate external contamination mechanisms. However, until now only the behavior of the whole sealing system was analyzed. A new testing method to understand the dirt particle transport between a reciprocating motioned rod and a wiper is presented. The new approach aims to avoid known issues such as limited reproducibility and long duration. The paper describes the test rig design and operating principle. First measurement results are shown.

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