Chapter 8.5

Chapter 8.5 - Fatigue: SN curves (III) In most alloys, S...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
21 MSE 2090: Introduction to Materials Science Chapter 8, Failure Fatigue: S—N curves (III) In most alloys, S decreases continuously with N. In this cases the fatigue properties are described by Fatigue strength : stress at which fracture occurs after a specified number of cycles (e.g. 10 7 ) Fatigue life : Number of cycles to fail at a specified stress level
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
22 MSE 2090: Introduction to Materials Science Chapter 8, Failure Fatigue: Crack initiation and propagation (I) Three stages of fatigue failure: 1. crack initiation in the areas of stress concentration (near stress raisers) 2. incremental crack propagation 3. final rapid crack propagation after crack reaches critical size The total number of cycles to failure is the sum of cycles at the first and the second stages: N f = N i + N p N f : Number of cycles to failure N i : Number of cycles for crack initiation N p : Number of cycles for crack propagation High cycle fatigue (low loads): N i is relatively high. With increasing stress level, N i decreases and N p dominates
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/14/2012 for the course MSE 2090 taught by Professor Leoindzhiglei during the Fall '10 term at UVA.

Page1 / 5

Chapter 8.5 - Fatigue: SN curves (III) In most alloys, S...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online