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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.
1

A Computational Iteration Method to Analyze Mechanics of Timing Belt Systems with Non-Circular Pulleys

Tan, Li 10 September 2018 (has links)
Timing belt systems, usually consisting of a toothed belt and multiple pulleys, are used in many mechanical devices, especially in the internal combustion engine to synchronize the rotation of the crankshafts and the camshafts. When the system operates, the belt teeth will be transmitted by the pulley teeth meshed with them. Timing belt drives can make sure that the engine' s valves open and close properly due to their precise transmission ratio. In this thesis, a quasi-static computational model is developed to calculate the belt load distributions and the torques around pulleys for different timing belt systems. The simplest system is a two-pulley system with one oval pulley and one circular pulley. This computational model is then extended to a two-pulley system with one special-shaped pulley and finally generalized to determine the load conditions for a multi-pulley system with multiple special-shaped pulleys. Belt tooth deflections, tooth loads, belt tension distributions, friction forces, and the effect of friction hysteresis have been taken into consideration. Results of these quantities are solved by a nested numerical iteration method. Periodic torques generated by the varied radius of noncircular pulley are calculated by this computational model to cancel the undesired external cyclic torque, which will increase the life of timing belts. / Master of Science / Timing belt systems, usually consisting of a toothed belt and multiple pulleys, are used in many mechanical devices, especially in the internal combustion engine to synchronize the rotation of the crankshafts and the camshafts. When the system operates, the belt teeth will be transmitted by the pulley teeth meshed with them. Timing belt drives can make sure that the engines valves open and close properly due to their precise transmission ratio. In this thesis, a quasi-static computational model is developed to calculate the belt load distributions and the torques around pulleys for different timing belt systems. The simplest system is a two-pulley system with one oval pulley and one circular pulley. This computational model is then extended to a two-pulley system with one special-shaped pulley and finally generalized to determine the load conditions for a multi-pulley system with multiple special-shaped pulleys. Belt tooth deflections, tooth loads, belt tension distributions, friction forces, and the effect of friction hysteresis have been taken into consideration. Results of these quantities are solved by a nested numerical iteration method. Periodic torques generated by the varied radius of noncircular pulley are calculated by this computational model to cancel the undesired external cyclic torque, which will increase the life of timing belts.
2

Improved lumped-parameter model for acoustic monitoring of tension in a timing belt used in automated material handling systems

Pizarek, Thomas Frederick 05 October 2011 (has links)
Automated Material Handling Systems are practically ubiquitous across industry and many rely on the operation of timing belt drives, which require that the belt be tensioned properly in order to function correctly. A series of experiments was carried out in which the frequency spectrum of acoustic radiation caused by transverse vibrations of a timing belt was used to calculate the belt tension. A lumped-parameter model was developed that considers the geometric complexity of the timing belt's construction by calculating the stiffness of a single belt tooth using commercially-available finite element analysis software. This was used to modify the belt's effective stiffness suggested by the manufacturer. Based on the experimental data, a set of material properties was determined that, when used in the lumped-parameter model, resulted in tension predictions that agreed with the experiment within the 95% confidence intervals of the means. / text
3

Design and Testing of a Novel Adhesion and Locomotion Method for Wall Climbing Vehicles

Stefani, Jim R 01 June 2016 (has links) (PDF)
The objective of this project was to design, construct and test a wall climbing vehicle which uses a novel vacuum tread system for both adhesion and locomotion. The design and manufacturing of this proof of concept vehicle is detailed with particular emphasis on the design decisions that proved most impactful to the performance of both the vehicle and the tread system. Adhesion performance was characterized by a series of tests that validate the concept, but also identify improvements and design recommendations for future embodiments of the adhesion/locomotion system.
4

Zvedák dopravníku s paletou / Hoist with a pallet conveyor

Hluzín, Filip January 2017 (has links)
This diploma thesis deals with the design of the conveyor lifter with a pallet according to specified parameters. The thesis includes functional, dimensional and strength calculations, control of the most stressed part using finite element method. Part of the thesis is also an assessment of the maintenance and operation requirements of the machine. The thesis is accompanied by drawing documentation of selected assemblies.
5

Konstrukční návrh standu pro zkoušení jednoválcového motoru / Stand for Single Cylinder Engine Testing

Sikora, Ondřej January 2018 (has links)
The diploma thesis deals with construction design of stand for testing single-cylinder turbocharged engine. The first part describes principles and possibilities of measuring the performance parameters of internal combustion engines. It also analyzes the issue of measuring single-cylinder combustion engine. The main part of thesis is about construction design of stand, which describes the individual technical solutions of the general construction parts. The last chapter deals with numerical simulation, which uses modern software tools. This software helps with verification of function design.
6

Elektronicky řízená dělící hlava / Electronically controled index head

Holík, Pavel January 2009 (has links)
Summary of structure design possibility. Proposal of structure design. Hardware proposal. Software proposal. Gearing calculation.
7

Návrh jednotné koncepce teleskopů manipulátorů přepravek pro zakladače typu Navette a SMC / Unified Design of Box Gripper Telescopes for Navette and SMC Storage Machines

Sojka, Michal January 2016 (has links)
The aim of this diploma thesis is unified design of box gripper telescopes for Navette and SMC storage machines. The work contains technical report and drawings documentation. The first part of technical report is aim to research of similar constructions used in the world. Followed by own construction solution, including needed calculation. At the final part of work was created a tolerance analysis of new telescope. The drawings documentation contains assembly and subassembly drawings.
8

Structured Neural Networks For Modeling And Identification Of Nonlinear Mechanical Systems

Kilic, Ergin 01 September 2012 (has links) (PDF)
Most engineering systems are highly nonlinear in nature and thus one could not develop efficient mathematical models for these systems. Artificial neural networks, which are used in estimation, filtering, identification and control in technical literature, are considered as universal modeling and functional approximation tools. Unfortunately, developing a well trained monolithic type neural network (with many free parameters/weights) is known to be a daunting task since the process of loading a specific pattern (functional relationship) onto a generic neural network is proven to be a NP-complete problem. It implies that if training is conducted on a deterministic computer, the time required for training process grows exponentially with increasing size of the free parameter space (and the training data in correlation). As an alternative modeling technique for nonlinear dynamic systems / this thesis proposed a general methodology for structured neural network topologies and their corresponding applications are realized. The main idea behind this (rather classic) divide-and-conquer approach is to employ a priori information on the process to divide the problem into its fundamental components. Hence, a number of smaller neural networks could be designed to tackle with these elementary mapping problems. Then, all these networks are combined to yield a tailored structured neural network for the purpose of modeling the dynamic system under study accurately. Finally, implementations of the devised networks are taken into consideration and the efficiency of the proposed methodology is tested on four different types of mechanical systems.
9

Simulation und Analyse ringgespannter Zahnriemengetriebe

Bankwitz, Hagen 03 November 2014 (has links) (PDF)
Die Arbeit befasst sich mit der Simulation von Zweiwellen-Zahnriemengetrieben und deren Vorspannmethoden, insbesondere mit der relativ neuen Methode Spannring (ROLL-RING®). Das Ziel der vorliegenden Arbeit ist es, ein analytisches Simulationsmodell zu entwickeln, mit dem grundlegende Erkenntnisse über das statische und dynamische Verhalten solcher ringgespannten Zahnriemengetriebe gewonnen werden können. Für einen exemplarischen Vergleich der Vorspannmethoden, werden außerdem analytische Simulationsmodelle für Zahnriemengetriebe ohne Spannelement und mit federgespannter Rolle erstellt. Als weiteren Bestandteil der vorliegenden Arbeit wird eine Dimensionierungsvorschrift für ringgespannte Zahnriemengetriebe abgeleitet, bei der sowohl statische als auch dynamische Vorgänge im Getriebe berücksichtigt werden können. Anschließend wird der Einfluss der relevanten Parameter auf das Verhalten des ringgespannten Getriebes untersucht. Alle erstellten Simulationsmodelle werden sowohl experimentell an Versuchsständen als auch mittels FEM-Vergleichsrechnung validiert. Die dafür benötigten Getriebeparameter wurden ebenfalls experimentell ermittelt. Abschließend folgt der exemplarische Vergleich der Vorspannmethoden anhand von drei Simulationsbeispielen und einem experimentellen Vergleich des Wirkungsgrads. / This dissertation deals with the simulation of two-shaft timing belt drive and its pre-tension methods. Special attention is given to the relatively new method tensioning ring (ROLL-RING®). The target of the present work is to develop an analytical simulation model, with this fundamental understanding of the static and dynamic behavior of such ring-tensioned timing belt drives can be gained. For an exemplary comparison of pre-tension methods, analytical simulation models for synchronous belt drive without pre-tension element and with tensioner pulley with spring will be created. As another part of the present work a dimensioning specification for ring-tensioned toothed belt drives was deduced. This specification can be considered in both static and dynamic processes in the transmission. Then, the influence of relevant parameters on the behavior of the ring-tensioned timing belt drives is researched. All created simulation models will vali-date both experimental and FEM using comparative calculation. The parameters re-quired for the transmission were also experimentally determined. Finally, the exemplary comparison of pre-tensioned methods basis of three examples of simulation and an ex-perimental comparison of energy conversion efficiency follow.
10

Rotační manipulátor pro ruční svařování bubnů zakladače EXYZ / Rotary manipulator for manual welding of hoist drums for EXYZ storage machine

Pečenka, Tomáš January 2017 (has links)
The main aim of this diploma thesis is to design rotary manipulator for manual welding of hoist drums for EXYZ storage machine. The rotary manipulator is designed for improving of the quality of welds, which have been made in the static bearing welding process of hoist drum. The first part is concerned on the critical research of welding manipulators, which could be founded on the market. In the next part, there are sketched possible construction designs of welding manipulator based on the market offer. The main part of the diploma thesis is own construction design, which is made on the base of suggested concept of construction design.

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