Analiza rezidualnih naprezanja u ispušnom kućištu plinske turbine

undergraduate thesis

• Title (english): Residual stress analysis in gas turbine exhaust housing
• Author: Karlo Seleš
• Mentor: Zdenko Tonković (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2015-02-26, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U ovom završnom radu provedena je numerička analiza zaostalih naprezanja i deformacija ispušnog kućišta plinske turbine, odnosno linera. Prije same numeričke analize, koja je vršena metodom konačnih elemenata u programskom paketu ABAQUS/STANDARD, dan je kratak osvrt o korištenim konačnim elementima te ispitana njihova konvergencija na primjeru ukliještene ploče opterećene vertikalnim pomakom po nasuprotnom rubu. Također, u sklopu uvoda u numeričku analizu, ispitana je opcija prebacivanja rezultata između analiza, korištenim elementima, na jednostavnom primjeru membranskog rastezanja tanke ploče, čiji je analitički postupak također prikazan.

Nakon ispitivanja konvergencije i verifikacije korištenih elemenata, izvršena je numerička analiza na jednoj desetini linera koristeći potrebne uvjete simetrije. Importirana geometrija na kojoj je izvršena analiza, te pomaci izmjereni nakon preddeformacije linera prije zavarivanja koji su korišteni za određivanje amplituda opterećenja, dobiveni su od strane tvrtke Alstom u svrhe izrade završnog rada u okviru projekta pod nazivom Razvoj i poboljšanje ispušnog sustava plinskih turbina (eng. Gas Turbine Exhaust System Enhanced Design) u suradnji s Fakultetom strojarstva i brodogradnje u Zagrebu. U sklopu numeričke analize ispitano je nekoliko načina zadavanja opterećenja u obliku pomaka po rubu modela, te je za usporedbu izvršena analiza s opterećenjem u obliku kontinuiranog tlaka po istom rubu na način da dobivena raspodjela pomaka bude što sličnija dobivenoj u analizi modela opterećenog pomakom. Za način zadavanja opterećenja u obliku pomaka po rubu modela koji je davao najrealniju raspodjelu pomaka po modelu, detaljnije je analizirana koncentracija naprezanja koja se javljaju u geometrijskim diskontinuitetima te je koristeći se metodom adaptivnog umrežavanja ispitana konvergencija ekvivalentnih naprezanja u tim područjima.

Abstract (english)

In this paper a numerical analysis of residual stress in Gas Turbine Exhaust Housing was conducted. Before the actual numerical analysis, which was performed using finite element method in software package ABAQUS/STANDARD, a brief review on used finite elements is given and their convergence is tested on the example of wedged plate loaded with vertical displacement at the opposite edge. Also, as part of the introduction to numerical analysis, the option of transferring the results between the analyses, with the used finite elements, has been tested on the simple example of membrane stretching of thin plate, whose analytical computing procedure has also been given.

After examination of convergence and verification of the elements used, numerical analysis has been performed on one-tenth of the liner, using necessary symmetry conditions. Imported geometry on which the numerical analysis has been performed, and measured displacements after the pre deformation of liner end radius which were used for determination of load amplitudes were given by Alstom company for composing of this paper in the framework of the project entitled Gas Turbine Exhaust System Enhanced Design in collaboration with the Faculty of Mechanical Engineering and Naval Architecture. Within the numerical analysis several types of application of loads in the form of model edge displacements has been analyzed. For comparison, the numerical analysis of load applied in the form of model edge pressure has been performed in such a way that the resulting distribution of displacement would be close to the one obtained in the analysis of model with applied load in form of displacement.

For the type of application of the load in the form of displacement along the edge model, which gave the most realistic displacement distribution, the stress concentrations that occur in geometric discontinuities has been analyzed more carefully using the adaptive meshing method.

• Keywords: Metoda konačnih elemenata; zaostala naprezanja; Abaqus; ispušno kućište plinske turbine.
• Keywords (english): Finite element method; residual stress; Abaqus; Gas Exhaust Housing
• Language: croatian
• URN:NBN: urn:nbn:hr:235:750491
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 13:05:37