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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

Designing of Kids Train

Bangalore Manjunath, Harsha, Kumar, Santosh January 2018 (has links)
Designing a Kids Train body and Chassis, where Body of a train plays an important role as it should be attractive, fun, educational, comfortable and safer for the kids. and the chassis should be able to withstand sufficient load and able to accommodate steering, battery, seating, motor, axles and bumper at all sides which is developed for SB international AB.A literature study is carried out to review various designs body of train and chassis, latest innovations and advanced materials used to manufacture the same. The various types of forces and stresses commonly acting on chassis structures are analyzed and their effects on the vehicle is understood and different types of train design is studied in order to make an attractive train for the kids by using Waterfall method to understand the concepts in designing a Train body. The pro-con analysis is conducted to evaluate merits and demerits of each alternative type of body of a train and the material to manufacture it. The most essential  design criteria are derived from the QFD (Quality function deployment) which then acts as important guidelines during the actual design process.Structural chassis frame is designed as per the design criteria with little modification and designing a body of a train using the CAD software CATIAV5R20 and the structural stability of the same is tested and analyzed using Inspire (solid thinking) software.
22

Design and Evaluatoin of a Carbon Fibre Bus Body

Nordin, David January 2018 (has links)
The automotive industry is in constant development and in recent years the environmental legislations have been getting tougher. The need for lighter and stronger materials has increased according to these changes and composite materials such as carbon fibre reinforced polymers is showing potential of being a solution due to their high specific properties. This thesis is an investigation and design proposal for one way of making a carbon fibre bus body wall structure by the use of pultruded beam elements and a certain number of standardised node elements. This is done to increase the possibility of mass production and possibly lower the manufacturing cost for a carbon fibre structure. The methodology is based on a product development process where a market research as well as a literary study was conducted initially to see what work had been done in the area. Needs were investigated and formulated to a product specification from which concepts was generated using brainstorming methods as well as discussions with bus design engineers at Scania. A number of materials and manufacturing methods was analysed for the node elements and after comparing and scoring different concepts, a carbon fibre node element was chosen. Dimensioning calculations were made based on standardised tests which simulates different driving scenarios. The concept was then designed in 3D-cad and the final weight of the concept was measured to 194 kg. A comparison of the concept with a steel bus was made by the use of the life cycle analysis tool in CES Edupack 2017 which resulted in a difference of 47 tonnes carbon dioxide released for a diesel driven light goods vehicle during the first six years of the lifetime. The overall results show that a carbon fibre bus body might be economically beneficial during the entire lifetime of a bus even though the purchase price is higher.
23

On Energy Efficient Mobile Hydraulic Systems : with Focus on Linear Actuation

Heybroek, Kim January 2017 (has links)
In this dissertation, energy efficient hydraulic systems are studied. The research focuses on solutions for linear actuators in mobile applications, with emphasis on construction machines. Alongside the aspect of energy efficiency, the thesis deals with competing aspects in hydraulic system design found in the development of construction machines. Simulation models and controls for different concepts are developed, taking the whole machine into account. In line with this work, several proof of concept demonstrators are developed. First, pump controlled systems are studied and a novel concept based on an open-circuit pump configuration is conceived. Special consideration is paid to multi-mode capabilities that allow for a broadened operating range and potential downsizing of components. Simulation models and controls are developed and the system is experimentally validated in a wheel loader application. Second, the possibility for energy recuperation in valve controlled systems is investigated. In such solutions, a hydraulic motor, added to the meter-out port, is used for energy recovery during load lowering and in multi-function operation. Recuperated energy is either be used momentarily or is stored in a hydraulic accumulator. The proposed solution means an incremental improvement to conventional systems, which is sometimes attractive to machine manufacturers due to fewer uncertainties in reliability, safety and development cost. The energy recovery system is studied on a conceptual level where several alternative systems are proposed and a concept based on a two-machine hydraulic pressure transformer is selected for a deeper control study followed by experimental validation. Third, so-called `common pressure rail' systems are suggested. This technique is well established for rotary drives, at least for the industrial sector. However, in applying this technique to mobile hydraulics, feasible solutions for linear actuators are needed. In this dissertation, two approaches to this problem are presented. The first one is the hydraulic pressure transformer, studied in simulation as the key-component of a `series hybrid' topology for wheel loaders. In the second approach variable displacement linear actuators (VDLA) based on a 4-chamber cylinder and multi-mode control is applied. In a theoretical study a model predictive control approach is suggested and new insights to the trade-off between controllability and energy efficiency of a multi-chamber cylinder are presented. Finally, a fullscale hydraulic hybrid system based on secondary controlled hydraulic motors and VDLAs is designed and experimentally validated on a large excavator.
24

High Speed Electric Vehicle Transmission : Investigation how noise vibration harshness are affected at high speeds in an electric vehicle transmission

Brauer, Samuel January 2017 (has links)
No description available.
25

Measures to Enhance the Dynamic Performance of Railway Catenaries

Liu, Zhendong January 2017 (has links)
The pantograph-catenary system is used in railways to transfer electric power from infrastructure to trainset. As the pantograph slides against the catenary, the contact between the two surfaces is not stable due to stiffness variation, propagating wave and other environmental perturbation, especially at high speeds or in multi-pantograph operation. Heavy oscillation can result in poor power-transmission quality, electromagnetic interference, severe wear or even structural damage. So the pantograph-catenary dynamics has become one of the key issues which limits the operational speed and determines the maintenance cost. There are many types of catenary systems in Sweden, which are relatively soft and sensitive compared with the systems in other countries. They work well at low operational speed and have strict limitations to multi-pantograph operation. It is possible to achieve an operational speed of 350 km/h on newly-built high-speed lines, but there is still a large demand for higher operational speed and more capacity on the existing lines.     Many researchers and engineers have made progress to improve its dynamic performance. From the research aspect, many numerical models have been built up to demonstrate the dynamics of the pantograph-catenary system and to unveil the key influencing factors. There have been many applications developed in recent years. Regarding the catenary, high-tensile loads on the catenary and low-stiffness-variation designs are widely used to improve the dynamic performance. Regarding the pantograph, aerodynamic-friendly designs and active-control technique contribute to the development of high-speed pantograph. But all these methods need not only large investment but long out-of-service. Considering the large scale and heavy service duty of the existing lines, it becomes almost impossible to completely upgrade the existing pantograph-catenary systems. So it is necessary to find practical and efficient methods to exploit the potentials of the existing systems to enhance their dynamic performances.     This thesis investigates the dynamic behaviour of the Swedish pantograph-catenary systems and proposes methods for better usage. A numerical study on multi-pantograph operation is performed and the relationships between dynamic performance and some key parameters is established. By studying the multi-pantograph operation at short spacing distance, a method to use the leading pantograph as auxiliary pantograph is proposed to increase the operational speed on the soft catenary system. To ensure operational safety in abnormal conditions, numerical studies on pantograph raising/lowering processes and in catenary overlap sections are performed. By studying the influence of the lumped-mass on the dynamic performance, it shows that it is even possible to implement some artificial tuned-masses on the catenary for dynamic optimization. / <p>QC 20170915</p>
26

Analys av kvalitetsproblemen på rear quarter panel stationen hos Volvo Cars i Torslanda / Analysis of the quality problems at rear quarter panel station at Volvo Cars AB in Torslanda

Korsbo, Andreas, Woxvold Bjönness, Egil January 2021 (has links)
Studien fokuserar på tillverkningen av Volvo v90. Mer specifikt monteringen av en expander runt tanklocket. Monteringen sker på rear quarter panel stationen och det finns ett kvalitetsproblem där. Den manuella monteringen görs inte rätt varje gång och detta leder till problem framöver i produktionen. Studiens syfte är att ta fram fler förslag till motåtgärder och förbättringar. Med hjälp av ett uppbyggt teoretiskt ramverk i form av andra vetenskapliga artiklar har ett flertal förslag tagits fram. Tre nya tekniker, några ändringar med Lean som riktlinjer och ett förslag till designändring beskrivs vidare i texten. Vidare ges även förslag på hur Volvo Cars kan arbeta vidare med förbättringsförslagen i framtiden för att upprätthålla hög kvalité. De metoder som används för att ta fram förslagen till motåtgärder är DMAIC, intervju, observation och en litteraturstudie. En analys genomförs för att utvärdera huruvida förslagen är försvarbara eller inte. Inget om själva implementeringen i verkligheten kommer att finnas med i rapporten / The present study analyzes the quality issues occurring during the assembly of the expander around the fuel cap while manufacturing Volvo v90. The assembling process is done manually at the rear quarter panel station. The main objective of the current investigation was to analyze the problems that Volvo Cars AB is facing currently and suggest quality improvement tools and techniques.  To define, measure and analyze the above-mentioned problem, the DMAIC method has been used. Interviews, observations, and a thorough literature study has been conducted and potential improvement proposals are suggested.  As a result of the current study, three new techniques for detecting quality problems early in the production process, several improvement suggestions with Lean as guideline and a suggestion for design change is proposed. Furthermore, suggestions are also given on how Volvo Cars can continue to work with improvements in the future to maintain a high quality throughout.
27

Load generation on a CV90 track system using multibody dynamics

Leiviskä, Albin January 2021 (has links)
No description available.
28

Towards Automatic and Systematic Compressor Model Selection Based on Measurement Data

Holmberg, Henrik January 2021 (has links)
Centrifugal compressors are mechanical devices that move and compress gas and are used in a wide range of applications. To get as much efficiency out of the compressors as possible, high demandsare put on having good compressor models. One method of compressor modeling is the curve fitting method, where empirical and mathematical models are used to parameterize relationships between different compressor characteristics. The models come in a vast variety of formats, complexity and difficulty of applying them. With the variety of compressors and models to select from, it is important to select an appropriate model. A tool for automatic parameterization, evaluation and selection of compressor model would be very useful. A model library is proposed in the thesis that utilizes the Total Least Squares method for parameterizing and evaluating the models. By initializing the model library with measurement data, called a compressor map, the compressor is broken down into smaller components in a hierarchy, based on physical expressions and characteristics. The individual compressor models are defined and parameterized on top of the base model, overriding and replacing the base model feature. Total Least Squares offers a countermeasure to avoid large model prediction errors associated with the nonlinear behavior of the compressor. To utilize the model library further, a simulation interface is proposed, so the selected compressor model can easily be applied in an engine and vehicle simulation environment. The model library is evaluated using three different compressor maps and shows promising results, where the TLS method seem to better capture bad visual curve-fitted models, compared to other simpler methods. Parameterization of the models are done automatically without any manual user input needed. The simulation interface is tested by replacing the compressor block of an engine simulation model, where the results show that the model component hierarchy can be integrated in a simulation environment.
29

Data-Driven Engine Fault Classification and Severity Estimation Using Interpolated Fault Modes from Limited Training Data

Säfdal, Joakim January 2021 (has links)
Today modern vehicles are expected to be safe, environmentally friendly, durable and economical. Monitoring the health of the vehicle is therefore more important than ever. As the complexity of vehicular systems increases the need for efficient monitoring methods has increased as well. Traditional methods of deriving models for the systems are today not as efficient as the complexity of the systems increases the time and skill needed to implement the models. An alternative is data driven methods where a collection of data associated with the behavior of the system is used to draw conclusions of the state of the system. Faults are however rare events and collecting sufficient data to cover all possible faults threatening a vehicle would be impossible. A method for drawing conclusions from limited historical data would therefore be desirable. In this thesis an algorithm using distiguishability as a method for fault classification and fault severity estimation is proposed. Historical data is interpolated over a fault severity vector using Gaussian process regression as a way to estimate fault modes for unknown fault sizes. The algorithm is then tested against validation data to evaluate the ability to detect and identify known fault classes and fault serveries, separate unknown fault classes from known fault classes, and estimate unknown fault sizes. The purpose of the study is to evaluate the possibility to use limited historical data to reduce the need for costly and time consuming data collection. The study shows promising results as fault class identification and fault size estimation using the proposed algorithm seem possible for fault sizes not included in the historical data.
30

Study of semi-empirical methods for ship resistance calculations

Petersson, Emil January 2020 (has links)
In the early ship design process a quick overview of which shipdesign that could be the optimal choice for the intended usage needsto be investigated. Therefore the feasibility and accuracy ofinterpolating between measurement data from model resistance serieswhen estimating unknown hulls were conducted. A parametric study wasundertaken in order to investigate which parameters carry the mostimportance in regard to calm water resistance for semi-displacinghulls. In order to asses the whole estimation process one semidisplacing ship (FDS-5) and one bulk carrier with a bulbous bow (JBC)were estimated in regard to calm water resistance by using semiempirical methods and were later compared with CFD results. The CFDresults came from a in part parallel conducted work. The resultsshowed that it is possible to estimate the total resistance withsemi-empirical methods to an unknown hull by linear interpolationwith an accuracy of below 5% in the designed speed interval both forFDS-5 and JBC. The CFD simulations achieved a lower accuracy comparedto the semi-empirical approach, however by furhter calibrating themodels, the accuracy could potentially be improved. Linearinterpolation between two hulls in order to estimate an unknown hull,is only advised when the hulls are nearly identical. Meaning that thehulls must be of the same ship type and that only one parameter isallowed to differ compared to the unknown hull. The parametric studyresulted in parameter importance in falling order: Slenderness ratio,length-beam ratio, longitudinal prismatic coefficient, blockcoefficient and beam-draught ratio. Even though the CFD approach notyet is completely reliable, it could still be a useful complement tothe semi-empirical approach by calculating parameters such as adynamic wetted surface, resistance due to appendages or airresistance of the full-scale ship. Simply by incrementally increasingthe accuracy of individual resistance components an overallimprovement could potentially be achieved.

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