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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.
481

Jeřáb radiální portálový / Radial gantry crane

Dias, Aleš January 2016 (has links)
The aim of my thesis is a conceptual design radial gantry crane including the important strength calculations according to the standards and examinations by means of ANSYS Workbench. The lifting capacity is 1500 kg, the length of the boom is 12 000 mm and the height of lifting is 3600mm. The crane is designed as fully revolving and the angle turning is 360°. The work also includes the selection of a suitable lifting gear from the manufacturer´s catalogue including the accessories casters, all important components and also FEM construction analysis.
482

Posouzení mostní konstrukce na účinky dynamického zatížení / An assessment of a bridge construction on a dynamic load

Součková, Markéta January 2017 (has links)
Diploma thesis deas with static and dynamic analysis of a steel arch footbridge. The footbridge structure 3D model was created in program ANSYS 12.1 and afterwards were made static and modal analysis on this computational model. Based on the results of~modal analysis was applied to design of dynamic wind loading on the model according to norms ČSN EN. The effects of this burden has been calculated steady response at resonance from harmonic analysis according to ČSN P EN 1991-2-4. To report according to ČSN EN 1991-1-4 was designed substitute quasistatic forces corresponding loads of wind on the construction and for evaluation was used static analysis.
483

Klopení nosníku - analýza specifických případů / Lateral-torsional buckling of beams - analysis of specific cases

Piják, Jiří January 2017 (has links)
Thesis deals with flexural-lateral buckling of asymmetric cross sections, especially assessment according to ČSN EN 1993-1-1. Models are based on bar, shell and solid finite element method. Assessment of software Scia Engineer and RFEM are analysed in bar model. Plate and volume model uses shell and solid elements and initial imperfections. Computing is geometrically nonlinear. Correspondence of bar and plate model is studied. Optimal amplitude is suggested. Simple beam loaded with continuous line loading is taken as an example.
484

Simulace momentové charakteristiky asynchronního stroje / Modeling of torque-speed characteristics of induction motor

Michalík, Marek January 2017 (has links)
This master thesis deals in first part with basic theory of an induction motor and principle of function. It also includes theory about higher harmonics of magnetic field and how asynchronous and synchronous torques are created. Various ways how to decrease effect of these torques are suggested. These findings are later applied in practical analytical calculation in second part, in which all parameters of motor are calculated from given dimensions of motor from technical documentation. This is done for basic and higher harmonics. After that a model of this motor was created in RMxprt program, which also calculated all parameters of this motor and created torque characteristic. This motor was also modelled in ANSYS Maxwell 2D. Additional simulations for finding out influence of harmonics on torque characteristic were also done in this software. Torque characteristic of motor was also practically measured in laboratory. All results were compared and evaluated.
485

CFD Simulations of Flow Characteristics of a Piano Key Weir Spillway

Sjösten, William, Vadling, Victor January 2020 (has links)
Comprehensive rehabilitation projects of dam spillways are made in Sweden, due to stricter dam safety guidelines for their discharge capacity. The Piano Key Weir (PKW) is an innovative design which has proven effective through several renovation projects made in many countries including France. In this study we investigate the flow patterns around a prototype PKW, located in Escouloubre dam in southern France, with numerical simulations through three different flow cases in Ansys Fluent. A computational domain containing the PKW is created in the CAD software Ansys SpaceClaim for the simulations. Three polyhexcore meshes are further generated using Ansys Fluent Meshing. The three flow cases are then simulated with a Reynolds-averaged Navier-Stokes (RANS) model, coupled with realizable k-epsilon and volume of fluid models. Through an assessment of the discretization error between three meshes, a relative error of one percent is obtained for the discharge rate. The numerical results are qualitatively compared with results from previously conducted physical experiments on this PKW. The RANS model does not capture the water surface undulations (due to turbulence) around the PKW. The effects from under modelled surface undulations are alleviated by inserting an air vent to the PKW, which results in a flow behaviour in good agreement with the physical experiments. Through this alteration, water discharge rates are computed with a maximum discrepancy of five percent compared with the corresponding experimental values. A large eddy simulation should be conducted in the future, to bring further light on air exchange and water interaction phenomena present in the PKW flow pattern.
486

Fatigue analysis of two wheel‐ mounted brake disc designs

Duranton, Coralie January 2015 (has links)
Due to a need of more compact bogies, the brake discs can be mounted on the railway wheels, bolted through the wheel web. Thus, the wheels are drilled and have multiple areas of contact with the brake discs. To establish maintenance procedures that will be applied to the  wheels,  SNCF  used  the  feedback  from  experience  (as  with  the  train  AGC)  which  gives  perfect  performance  in  terms  of  safety.  However,  to  optimize  the  maintenance  process, numerical  simulations  may  be  preferred  since  they  are  less  conservative.  This  report  describes  the  numerical  simulations,  based  on  the  finite  element  method,  that  were conducted to determine if the Régiolis wheel complies with the standard EN 13979-­‐1 from a mechanical  fatigue  point  of  view.  In  addition,  it  provides  additional  insights  regarding  the  loads and damage suffered by the wheel, which are not taken into account in the standard: the  damage  induced  by  disc  braking  and  the  fretting  that  may  occur  at  the  contact  interfaces. This study has been used as a decision support for the first inspection intervals of the Régiolis wheels.
487

Dimensioning of a cutter wheel bearings / Dimensionering av lagring till cutterhjul

Xie, Kebin January 2020 (has links)
Mobile Miner 40V is a machine used for rock excavation and developed by Epiroc. This machine is equipped with a large cutter wheel to perform the excavation. After a test run, some surfaces associated with bearings within the cutter wheel were found to be damaged due to scuffing - severe sliding wear. There is a static load applied to the surfaces due to gravity. However, the reason for this damaged issue was believed that there is a large dynamic load applied to the surfaces during the excavation. This dynamic load was not found in a previous FE model used to verify safety issues. Therefore, a new FE model that is more in line with reality, and a failure analysis were required. Additionally, a feasibility study for a cutter wheel with a larger dimension was also needed since a larger cutter wheel is desirable. Firstly, wear mechanisms were reviewed, and some theories were chosen to analyze the damaged issue. Since it was unknown whether the surfaces were well-lubricated or not, both cases were investigated. The Archard wear equation was used to analyze the poor-lubricated situation, while the lubrication number and the Reynolds equation were used to analyze the well-lubricated case. Secondly, contact mechanisms between the surfaces were also investigated. The investigation of the contact mechanisms involved several theories, such as the Hertzian contact theory and the impact load factor. Besides these theoretical analyses, a numerical analysis was performed. Lastly, a new FE model was established in Ansys. Both the cutter wheel which was subjected to scuffing(existing cutter wheel), and the cutter wheel with a larger dimension(larger cutter wheel) were analyzed by the use of the new FE model. The maximum and minimum wear rates obtained by the Archard wear equation are approximately 1.9・10-2mm3/m and 4.8・10-3mm3/m, which are considered as a completely unacceptable level in engineering applications. The maximum and minimum critical loads obtained by the Reynold equation are approximately 1.8kN and 24.8kN, which both are larger than the static load applied to the surfaces. The maximum and minimum critical mean contact pressures obtained by the lubrication number are approximately 65MPa and 240MPa, which both are larger than the mean contact pressure generated by the static load. No evidence shows that there is a large dynamic load applied to the surfaces during the excavation. The largest possible contact pressure on the bearings in the existing cutter wheel is very close to the limit of severely damaged. The largest possible contact pressure on the bearings in the larger cutter wheel is believed to exceed the limit of severely damaged. The previous assumption that the surfaces were damaged due to a large dynamic load was wrong. The obtained results support that the surfaces were only subjected to a static load and were damaged due to inadequate lubrication. The existing cutter wheel is operated safely with the current load cases. However, the forward thrust force is suggested to decrease when the cutting angle is large. There is a high risk if the larger cutter wheel is operated with the current load cases.
488

Design and Analysis of a Composite Monocoque for Structural Performance : a Comprehensive Approach

Kamble, Meghana P. 08 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Lately numerous studies have been performed to design composite monocoques with high strength and low weight for various student level racing contests. The objective of this paper is to develop an insightful methodology to design and de veloped a light-weight composite monocoque. The monocoque is designed to pass the mandatory static load tests laid down by the International Automobile Feder ation (FIA)Formula 3. These Formula 3 tests are considered the baseline of the desired structural integrity of the composite monocoque. The presented design tech nique emphasises on a monocoque developed for Sports Car Club of America (SCCA) races. The three standard load tests performed on the monocoque are Survival Cell Side test, Fuel Tank test and Side Intrusion test. A sandwich layup of bi-directional woven carbon/epoxy prepreg and aluminium honeycomb is optimized for minimum weight while predicting the unknown properties of layup and ensuring the mono coque doesnt experience failure. The approach intends to achieve minimum weight with high torsional rigidity and is capable of being used for the design and analysis of any kind of formula type composite monocoque.
489

Numerické modely pro posuzování stability zemního svahu / Numerical Patterns for Evaluation of the Stability Slope

Ekr, Jan January 2012 (has links)
The master’s thesis deals with numerical patterns for evaluation of the stability slopes. Solutions have been made with finite element method for different design situations with using programme system ANSYS. The results were compared with conventional approaches determining of the slope safety factor.
490

Statická analýza částí potrubních systémů z termoplastů / Static Analysis of Parts of Thermoplastic Pipe Systems

Plášek, Jan January 2018 (has links)
Thermoplastic materials have significant nonlinear behaviour. The nonlinear behaviour is described by creep curves. The curves of creep modules are dependent on stress, temperature and time. The dissertation thesis deals with the approximation of the creep modules by Prony series. Subsequently three procedures are proposed to take account of creep modules. The proposed procedures are used in two applications. The first application deals with the ring stiffness value of a corrugated sewage pipe. The ring stiffness value is influenced by the creep modulus. The other one deals with a thermoplastic flange connection. The clamping force is dependent on the creep modulus of thermoplastics. The problems were solved by ANSYS program system.

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