INTRODUCTION - Universiti Teknologi taminmn/SKMM4133_Module_1_ آ  INTRODUCTION M.N. Tamin,

download INTRODUCTION - Universiti Teknologi taminmn/SKMM4133_Module_1_ آ  INTRODUCTION M.N. Tamin,

of 12

  • date post

    07-May-2020
  • Category

    Documents

  • view

    0
  • download

    0

Embed Size (px)

Transcript of INTRODUCTION - Universiti Teknologi taminmn/SKMM4133_Module_1_ آ  INTRODUCTION M.N. Tamin,

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    MODULE 1

    INTRODUCTION

    SKMM 4133 Failure of Engineering Components and Structures

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    Fatigue crack in root area of

    a turbine blade

    List possible questions regarding this fracture situation

    OPENING REMARKS

    SKMM 4133 Failure of Engineering Components and Structures

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    • Failure

    Inability of a component to perform

    according to its intended function.

    • Failure Analysis

    The examination of a failed component

    and of the failure situation in order to

    determine the causes of failure

    Failure Analysis of Metallic Components

    SKMM 4133 Failure of Engineering Components and Structures

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and StructuresSKMM 4133 Failure of Engineering Components and Structures

    Week Date

    (Sun.)

    Lecture & Topics

    TopicsLecture

    1

    Lecture

    2

    Lecture

    3

    1 07 Sep A A A

    A – Introduction

    - Overview

    - Requirements and approach

    B – Static failure due to overload

    and instability.

    C – Fatigue failure

    - High-cycle fatigue

    - Low-cycle fatigue

    D – Creep and stress rupture

    E – Fatigue crack propagation

    (OPTIONAL) – Computational aspects of

    failure analysis

    2 14 Sep A A A

    3 21 Sep B B B

    4 28 Sep B B B

    5 05 Oct C C C

    6 12 Oct C C C

    7 19 Oct SEMESTER BREAK

    8 26 Oct Test1 C C

    9 02 Nov C C C

    10 09 Nov C C C

    11 16 Nov D D D

    12 23 Nov D D D

    13 30 Nov E E E

    14 07 Dec E E E

    15 14 Dec E Test 2 Closure

    16 21 Dec STUDY LEAVE

    17 28 Dec FINAL EXAMINATION

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    COURSE CONTENT

    1.0 Introduction

    Historical background, origin, detection and prevention of failure, types of

    mechanical failure: gross yielding, fatigue fracture, buckling, creep

    rupture, review of stress field and stress concentration, statistical aspect of

    failure analysis, loading spectrum, metallurgical aspect of component

    failure.

    2.0 Materials Defects

    Processing-structure-property relationship, metallurgical imperfection,

    processing defects, NDT methods, surface defects and corrosion,

    propagation of defects, tools for metallurgical failure analysis

    3.0 Failure due to overload

    Yield failure theories, idealized material behavior, plastic bending of

    beams, collapse loads, plastic torsion of circular bar, residual stresses after

    yielding.

    4.0 Buckling of Struts and Columns

    Euler’s column theory, Rankine-Gordon formula, eccentric loading,

    inelastic buckling.

    SKMM 4133 Failure of Engineering Components and Structures

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    COURSE CONTENT (Continued)

    5.0 Fatigue Failure

    High-cycle fatigue, Strength-life (S-N) curves, cumulative damage

    concept, life prediction and fracture control; low-cycle fatigue, strain

    cycling concept, strain-life curve and low-cycle fatigue relations,

    influence of non-zero mean strain and non-zero mean stress.

    6.0 Creep and Stress Rupture

    Theories for predicting creep behavior, Larson-Miller and Manson-Haferd

    parameters, uniaxial and multi-axial state of stress, cumulative creep

    concept, creep-fatigue interaction.

    7.0 Fatigue Crack Propagation and Control

    Basics of fracture mechanics, linear elastic and elastic-plastic fracture

    mechanics, stress intensity factor range, fatigue crack growth rate, factors

    affecting crack propagation, fatigue fracture mechanisms in metals.

    SKMM 4133 Failure of Engineering Components and Structures

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    COVERAGE

    • CONCEPT

    • FUNDAMENTAL THEORY

    • ESTABLISHED WORK

    • STATISTICS

    • CASE STUDIES

    SKMM 4133 Failure of Engineering Components and Structures

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    SCOPE

    MODES OF FAILURE

    • Gross Yielding

    • Fatigue Fracture

    • Creep Rupture

    • Buckling

    • Static Delayed Fracture

    REQUIREMENTS FOR FAILURE

    ANALYSIS

    • Mechanical design and analysis

    • Force analysis

    • Stress analysis

    • Chemical analysis

    • Metallography

    • Fractography

    • Mechanical testing

    • Failure simulation

    SKMM 4133 Failure of Engineering Components and Structures

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    Faulty design considerations/

    misapplication of materials

    • Ductile failure – excessive

    deformation (elastic or plastic),

    tearing or shear fracture).

    • Brittle fracture – from flaws and

    critical stress raisers.

    • Fatigue failure – due to time-

    varying load, thermal cycling,

    corrosion fatigue.

    • High-temperature failure – creep,

    oxidation, local melting, warping.

    • Static delayed fracture – hydrogen

    embrittlement,

    • Severe stress raiser inherent

    in design.

    • Inadequate stress analysis

    • Mistake in designing on

    basis of static tensile

    properties only

    Classification of the causes of failure

    SKMM 4133 Failure of Engineering Components and Structures

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    Faulty processing

    • Flaws due to faulty composition –

    wrong material, inclusions,

    embrittling impurities.

    • Defects originating in ingot

    making and casting – porosity, non-

    metallic inclusions, segregation.

    • Defects due to working – laps,

    seams, hot-short splits, excess local

    deformation

    • Irregularities / mistakes due to

    machining, grinding or stamping –

    burns, tearing, cracks.

    • Welding defects – voids, undercuts,

    residual stresses, HAZ, lack of

    penetration.

    •Abnormalities due to heat treatment –

    grain growth, precipitation, excessive

    retained austenite, decarburization.

    • Flaws due to case hardening –

    intergranular carbides, soft core.

    • Defects due to surface treatment –

    plating, chemical diffusion, hydrogen

    embrittlement.

    • Parting-line failure in forging - due

    to poor transverse properties.

    • Careless assembly – mismatch of

    mating parts, residual stress, gouges.

    Classification of the causes of failure

    SKMM 4133 Failure of Engineering Components and Structures

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    Deterioration in service

    • Overload / unforeseen loading

    conditions

    • Wear – erosion, galling,

    seizing, cavitation.

    • Corrosion – chemical attack,

    stress corrosion, dezincification.

    • Inadequate / misdirected

    maintenance or improper repair

    – welding, grinding, cold

    straightening.

    • Disintegration by chemical

    attack, attack by liquid metals or

    plating at elevated temperature

    • Radiation damage -

    decontamination may destroy

    evidence for the cause of failure.

    • Accidental condition – abnormal

    operating temperature, severe

    vibration, impact, thermal shock.

    Classification of the causes of failure

    SKMM 4133 Failure of Engineering Components and Structures

  • INTRODUCTION M.N. Tamin, UTM

    SME 4133 Failure of Engineering Components and Structures

    • Description of the failure situation –

    Background information, history of

    usage, design of component.

    • Visual inspection – DO NOT damage

    the fracture surface.

    • Mechanical design analysis (stress

    analysis) – to establish the cause of

    failure. Was the part of sufficient size?

    • Chemical design analysis –to establish

    the suitability of the material wrt

    corrosion resistance.

    • Fractography – examine fracture

    surface to establish the mechanism of

    fracture.

    • Metallographic examination – to help

    establish such facts as whether the part

    has correct heat treatment.

    • Determine properties – to establish

    properties pertinent to the design.

    • Failure simulation - to establish

    response of identical component under

    exact condition of loading, numerical