Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
A hybrid model of stress-life and strain-life fatigue used to predict high power electrical rotating machines fan fatigue damage.
Submission Author:
Pedro Martins de Oliveira , BA
Co-Authors:
Pedro Martins de Oliveira, Angelo Carvalho, Bruna Luiza dos Santos
Presenter: Pedro Martins de Oliveira
doi://10.26678/ABCM.COBEM2023.COB2023-2017
Abstract
High power electrical rotating machines are generally designed with one or more fans assembled directly on its shaft to force some air to cool down its core. It is common the usage of fans with elevated peripherical speed due to the large dimensions of the machines or to high angular speed of the electrical motor or generator, this generates high stress on the weld notch and tip of the blade. Because of that, fatigue damage on high power electrical rotating machines fan blade is crucial to perform their design to ensure reliability to operate on a predetermined number of cycles. However, due to its complex geometry multiple zones are subjected to critical loads, these loads generate notch stresses where there are welds and high strains in the tip of the blades and the weld root. Therefore, a hybrid model is proposed evaluate the damage of a stress-life fatigue method coupled with a strain-life fatigue method. In order to validate the method under study, rolled carbon steel AISI 1020 mechanical proprieties were obtained using the software Granta. A prototype was used in test conditions to predict the failure mechanics of the tip of the blade, and a comparison to the separated methods was used to validate the technical feasibility. The stress life fatigue used in the weld gives a conservative view of the component life and the strain-life method alone is feasible if the weld has a high safety factor. The coupled method provides a bolder predication on high stress and strain near the weld notch where high stress and strains are present.
Keywords
fatigue, failure analysis, Eletrical rotating machine
