Spectral Method for Fatigue Damage Estimation with Non-Zero Mean Stress / Pedro H. Alves Corrêa.

Format:

Book

Author/Creator:

Alves Corrêa, Pedro H., author.

Language:

English

Subjects (All):

Materials--Fatigue.

Materials.

Physical Description:

1 online resource (66 pages)

Edition:

First edition.

Place of Publication:

[Place of publication not identified] : Editora Dialética, [2022]

Summary:

This thesis consists of a fatigue study carried out on an aluminum alloy 2024-T3 in both time domain and frequency domain. Non-zero mean random signals of strain and stress are analyzed in time domain using usual Rainflow method and the damage is accumulated with the Palmgren-Miner rule, according to mean stress equations. The signals are analyzed in frequency domain using the power spectral density and the probability density function. The spectral domain analysis does not consider the negative effect of the mean stress in metal life under fatigue, so the correction factors for mean stresses developed by Goodman, Morrow, and Smith-Watson-Topper are used to change the power spectral density and, thus, the damage calculated by the probability density functions postulated by Dirlik and Tovo and Benasciutti. It is found that both Dirlik and Tovo and Benasciutti are non-conservative for a non-zero mean stress signal when comparing the damage to the one obtained in time domain analysis. When the spectral method is corrected, the results vary from Rainflow 4.9% for wide band and 6.8% for narrow band signals, always in the conservative zone, therefore predicting more damage. Tovo and Benasciutti 2 method is found to be the spectral function with the closest results when compared to the usual Rainflow method in time domain.

Contents:

Folha de Rosto

Créditos

1. Introduction

1.1 Motivation

1.2 Objectives

2. Theoretical Fundamentals

2.1 Cyclic Loading

2.2 Fatigue of Materials

2.3 Mean Stress Correction

2.4 Rainflow Cycle Counting

2.5 Palmgren-Miner Rule

2.6 Spectral Fatigue

2.7 Random Loading

2.7.1. Stationary Random Loading

2.7.2. Ergodic Stationary Random Loading

2.7.3. Gaussian distribution

2.8 Power Spectral Density

2.9 Wide Band and Narrow Band Processes

2.10 Moments of the PSD

2.11 Fatigue Analysis Within Frequency Domain

2.11.1. The Rayleigh Method

2.11.2. Tovo-Benasciutti Method

2.11.3. Dirlik Method

2.12 Global Mean Stress Value

3. Materials and Methods

3.1 Materials and Equipment

3.1.1. Material

3.1.2. Specimen

3.1.3. Data Acquisition

3.2 Experimental Set Generated by AI.

Notes:

Includes bibliographical references.

Description based on publisher supplied metadata and other sources.

Part of the metadata in this record was created by AI, based on the text of the resource.

Description based on print version record.

Other Format:

Print version: Corrêa, Pedro H. Alves Spectral Method for Fatigue Damage Estimation with Non-Zero Mean Stress

ISBN:

9786525253213

OCLC:

1338837423