R&B Technical Note TN16 Fatigue & Fracture Toughness Test · 2020. 2. 18. · TN 16 Fatigue & Fracture Toughness Test , [email protected] 본 자료는 R&B Inc.의 자료로 무단

R&B Technical Note TN16

Fatigue & Fracture Toughness Test

K CTOD J Integral Small Punch Fatigue Impact R&B Inc. MTS BUSINESS PARTNER Copy Right, R&B Inc. Design and specification can be changed for quality improvement RB343_REV1 Printed 02/2020

TN 16 Fatigue & Fracture Toughness Test

www.randb.co.kr, [email protected]

본 자료는 R&B Inc.의 자료로 무단 복사 및 도용을 금합니다. 2/21

Content

Preface 3

Hyperlink List 4

I. Introduction 6

II. Fatigue Test 7

III. Fracture Toughness Test 10

IV. Impact Test 14

V. Small Punch Test 16

VI. Crack Tunneling 17

VII. Crack Measuring Method 18

R&B TEST ROPE Solution 19

R&B Information 19

Epilog 20

http://www.randb.co.kr/mailto:[email protected]




Preface

Dynamic Test의 대표적인 시험으로 Fatigue, Fracture, Impact 시험방법을 정리한 자료로서

R&B 경험을 바탕으로 자료를 소개합니다.

자료는 Hyperlink 처리하여 필요에 따라 사용할 수 있도록 구성하였습니다.

Hyperlink List

▪ 관련자료 56File





Hyperlink List

No. Standard Number

Title Field

1 ASTM B593 Bending Fatigue Testing for Copper Alloy Spring Materials 한글 Fatigue

2 ASTM D3479 Tension-Tension Fatigue of Polymer Matrix Composite Materials 한글 Fatigue

3 ASTM D7774 Standard Test Method for Flexural Fatigue Properties of Plastics 한글 Fatigue

4 ASTM E466 Conducting Force Controlled Constant Amplitude Axial Fatigue Tests of Metallic

Materials 한글 Fatigue

5 ASTM E468 Presentation of Constant Amplitude Fatigue Test Results for Metallic Materials 한글 Fatigue

6 ASTM E606 Strain Controlled Fatigue Testing 한글 Fatigue

7 ASTM E739 Statistical Analysis of Linear or Linearized Stress-Life (S-N) and Strain-Life (ε-N) Fatigue Data

한글 Fatigue

8 ASTM E1942 Data Acquisition Systems Used in Cyclic Fatigue 한글 Fatigue

9 ASTM E2207 Strain-Controlled Axial-Torsional Fatigue Testing with Thin- Walled Tubular Specimens 한글 Fatigue

10 ASTM E2714 Creep Fatigue Testing 한글 Fatigue

11 ASTM E647 Measurement of Fatigue Crack Growth Rates Fatigue

12 Summary Fatigue Test Seminar Fatigue

13 ASTM B909 Plane Strain Fracture Toughness Testing of Non Stress Relieved Aluminum Products 한글 Fracture

14 ASTM C1368 Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress

Rate Strength Testing at Ambient Temperature 한글 Fracture

15 ASTM C1421 Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature 한글 Fracture

16 ASTM D5045 Plane Strain Fracture Toughness and Strain Energy Release 한글 Fracture

17 ASTM D6068 Determining JR Curves of Plastic Materials 한글 Fracture

18 ASTM D6671 Mixed Mode I-Mode II Interlaminar Fracture Toughness of Unidirectional Fiber Reinforced

Polymer Matrix Composites 한글 Fracture

19 ASTM D7779 Determination of Fracture Toughness of Graphite at Ambient Temperature 한글 Fracture

20 ASTM E399 Linear-Elastic Plane-Strain Fracture Toughness KIC of Metallic Matrials 한글 Fracture

21 ASTM E561 Standard Test Method for KR Curve Determination 한글 Fracture

22 ASTM E740 Fracture Testing with Surface Crack Tension Specimens 한글 Fracture

23 ASTM E1221 Determining Plane Strain Crack Arrest Fracture Toughness, KIa, of Ferritic Steels 한글 Fracture

24 ASTM E1290 Crack-Tip Opening Displacement (CTOD) Fracture Toughness Measurement (Withdrawn

2013) 한글 Fracture

25 ASTM E1304 Plane Strain (Chevron Notch) Fracture Toughness of Metallic Materials 한글 Fracture

26 ASTM E1681 Determining Threshold Stress Intensity Factor 한글 Fracture

27 ASTM E1820 Measurement of Fracture Toughness 한글 Fracture

28 ASTM E1823 Standard Terminology Relating to Fatigue and Fracture Testing 한글 Fracture

29 ASTM E1921 Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range

한글 Fracture

http://www.randb.co.kr/mailto:[email protected]://www.randb.co.kr/wp-content/uploads/2018/06/ASTM-B593-Bending-Fatigue-Testing-for-Copper-Alloy-Spring-Materials-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ASTM-D3479-Tension-Tension-Fatigue-of-Polymer-Matrix-Composite-Materials-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-D7774-Standard-Test-Method-for-Flexural-Fatigue-Properties-of-Plastics-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E466-Conducting-Force-Controlled-Constant-Amplitude-Axial-Fatigue-Tests-of-Metallic-Materials-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E466-Conducting-Force-Controlled-Constant-Amplitude-Axial-Fatigue-Tests-of-Metallic-Materials-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E468-Constant-Amplitude-Fatigue-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E606-Strain-Controlled-Fatigue-Testing-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E739-Stress-Life-S-N한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E739-Stress-Life-S-N한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1942-Data-Acquisition-Systems-Used-in-Cyclic-Fatigue-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ASTM-E2207-Strain-Controlled-Axial-Torsional-Fatigue-Testing-with-Thin-Walled-Tubular-Specimens-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E2714-09Standard-Test-Method-for-Creep-Fatigue-Testing-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E647-Measurement-of-Fatigue-Crack-Growth-Rates-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/Fatigue-test-Seminar.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/06/ASTM-B909-Plane-Strain-Fracture-Toughness-Testing-of-NonStress-Relieved-Aluminum-Products-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/06/ASTM-C1368-Determination-of-Slow-Crack-Growth-Parameters-of-Advanced-Ceramics-by-Constant-Stress-Rate-Strength-Testing-at-Ambient-Temperature-한글1.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/06/ASTM-C1368-Determination-of-Slow-Crack-Growth-Parameters-of-Advanced-Ceramics-by-Constant-Stress-Rate-Strength-Testing-at-Ambient-Temperature-한글1.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/06/ASTM-C1421-Determination-of-Fracture-Toughness-of-Advanced-Ceramics-at-Ambient-Temperature-한글1.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-D5045-Plane-Strain-Fracture-Toughness-and-Strain-Energy-Release-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-D6068-Determining-JR-Curves-of-Plastic-Materials-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ASTM-D6671-Mixed-Mode-I-Mode-II-Interlaminar-Fracture-Toughness-of-Unidirectional-Fiber-Reinforced-Polymer-Matrix-Composites-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ASTM-D6671-Mixed-Mode-I-Mode-II-Interlaminar-Fracture-Toughness-of-Unidirectional-Fiber-Reinforced-Polymer-Matrix-Composites-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-D7779-Determination-of-Fracture-Toughness-of-Graphite-at-Ambient-Temperature-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E399-Linear-Elastic-Plane-Strain-Fracture-Toughness-KIC-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E561-Standard-Test-Method-for-KR-Curve-Determination-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E740-Fracture-Testing-with-Surface-Crack-Tension-Specimens-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1221-Determining-Plane-Strain-Crack-Arrest-Fracture-Toughness-KIa-of-Ferritic-Steels한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1290-CTOD-Fracture-Toughness-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1290-CTOD-Fracture-Toughness-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1304-97-Plane-Strain-Chevron-Notch-Fracture-Toughness-of-Metallic-Materials-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1681-Determining-Threshold-Stress-Intensity-Factor-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1820-Measurement-of-Fracture-Tughness-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1823-Standard-Terminology-Relating-to-Fatigue-and-Fracture-Testing-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1921-Determination-of-Reference-Temperature-for-Ferritic-Steels-in-the-Transition-Range-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1921-Determination-of-Reference-Temperature-for-Ferritic-Steels-in-the-Transition-Range-한글.pdf




30 ASTM E1922 Translaminar Fracture Toughness of Laminated and Pultruded Polymer Matrix

Composite Materials 한글 Fracture

31 BS 7448 Part 2

Fracture mechanics toughness tests. Method for determination of KIc, critical CTOD and critical J values of welds in metallic materials

Fracture

32 Paper Local compression 에 의한 crack tunneling 방지법 Fracture

33 Paper Modelling of fatigue crack tunneling and delamination in layer composite Fracture

34 Paper Reverse bending 에 의한 crack tunneling 방지법 Fracture

35 Paper Difference between ASTM E1290 and BS 7448 CTOD Estimation Procedures Fracture

36 ASTM F2183 Small Punch Testing of Ultra-High Molecular Weight Polyethylene Used in Surgical

Implants 한글 Small Punch

37 ASTM F2977 Small Punch Testing of Polymeric Biomaterials Used in Surgical Implants 한글 Small Punch

38 Paper Recent developments in small punch testing 한글 Small Punch

39 Summary Small punch 시험법 Small Punch

40 ASTM D2444 Determination of the Impact Resistance of Thermoplastic Pipe and Fittings by Means of a Tup

한글 Impact

41 ASTM D256 Determining The Izod Pendulum Impact Resistance of Plastics Impact

42 ASTM D3763 High Speed Puncture Properties of Plastics Using Load and Displacement Sensors 한글 Impact

43 ASTM D522 Mandrel Bend Test of Attached Organic Coatings 한글 Impact

44 ASTM D5628 Impact Resistance of Flat, Rigid Plastic Specimens by Means of a Falling Dart 한글 Impact

45 ASTM D6110 Determining the Charpy Impact Resistance of Notched Specimens of Plastics Impact

46 ASTM D7192 High Speed Puncture Properties of Plastic Films Using Load and Displacement Sensors

한글 Impact

47 ASTM E1236 Qualifying Charpy Impact Machines as Reference Machines 한글 Impact

48 ASTM E208 Conducting Drop Weight Test to Determine Nil Ductility Transition Temperature of Ferritic

Steels 한글 Impact

49 ASTM E23 Notched Bar Impact Testing of Metallic Materials 한글 Impact

50 ASTM E436 Drop Weight Tear Tests of Ferritic Steels 한글 Impact

51 ASTM E602 Sharp Notch Tension Testing with Cylindrical Specimens 한글 Impact

52 ASTM E604 Dynamic Tear Testing of Metallic Materials 한글 Impact

53 ISO 14556 Charpy V-notch pendulum impact test- Instrumented method 한글 Impact

54 GMW16086 Evaluation for Susceptibility to Secondary Cold Work Embrittlement 한글 Impact

55 ASTM D7136 Measuring the Damage Resistance to impact Impact

56 ISO 148-1 Metallic materials - Charpy pendulum impact test -Part 1 Test method Impact

http://www.randb.co.kr/mailto:[email protected]://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1922-Translaminar-Fracture-Toughness-of-Laminated-and-Pultruded-Polymer-Matrix-Composite-Materials-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1922-Translaminar-Fracture-Toughness-of-Laminated-and-Pultruded-Polymer-Matrix-Composite-Materials-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/BS-7448-Part-2-1997-Fracture-mechanics-toughness-tests-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/BS-7448-Part-2-1997-Fracture-mechanics-toughness-tests-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/Local-compression에-의한-crack-tunneling-방지법.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/Modelling-of-fatigue-crack-tunneling-and-delamination-in-layer-composite.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/Reverse-bending에-의한-crack-tunneling-방지법.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/04/Difference-between-ASTM-E1290-and-BS-7448-CTOD-Estimation-Procedures-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-F2183-Small-punch한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-F2183-Small-punch한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ASTM-F2977-13-Small-Punch-Testing-of-Polymeric-Biomaterials-Used-in-Surgical-Implants-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/Recent-developments-in-small-punch-testing-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/Small-punch-시험법.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-D2444-Determination-of-the-Impact-Resistance-of-Thermoplastic-Pipe-and-Fittings-by-Means-of-a-Tup-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-D2444-Determination-of-the-Impact-Resistance-of-Thermoplastic-Pipe-and-Fittings-by-Means-of-a-Tup-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/ASTM-D256-Determining-the-Izod-Pendulum-Impact-Resistance-of-Plastics-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-D3763-High-Speed-Puncture-Properties-of-Plastics-Using-Load-and-Displacement-Sensors한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-D522-Mandrel-Bend-Test-of-Attached-Organic-Coatings-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-D5628-Impact-Resistance-of-Flat-Rigid-Plastic-Specimens-by-Means-of-a-Falling-Dart-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/ASTM-D6110-Determining-the-Charpy-Impact-Resistance-of-Notched-Specimens-of-Plastics-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ASTM-D7192-High-Speed-Puncture-Properties-of-Plastic-Films-Using-Load-and-Displacement-Sensors-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ASTM-D7192-High-Speed-Puncture-Properties-of-Plastic-Films-Using-Load-and-Displacement-Sensors-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E1236-Qualifying-Charpy-Impact-Machines-as-Reference-Machines-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E208-Conducting-Drop-Weight-Test-to-Determine-Nil-Ductility-Transition-Temperature-of-Ferritic-Steels한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E208-Conducting-Drop-Weight-Test-to-Determine-Nil-Ductility-Transition-Temperature-of-Ferritic-Steels한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E23-Notched-Bar-Impact-Testing-of-Metallic-Materials-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E436-Drop-Weight-Tear-Tests-of-Ferritic-Steels-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E602-Sharp-Notch-Tension-Testing-with-Cylindrical-Specimens-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E604-83-Dynamic-Tear-Testing-of-Metallic-Materials-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ISO-14556-Charpy-V-Instrumented-impact-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/GMW16086-2009-Evaluation-for-Susceptibility-to-Secondary-Cold-Work-Embrittlement한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ASTM-D7136-Measuring-the-Damage-Resistance-to-impact-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ISO-148-1-Metallic-materials-Charpy-pendulum-impact-test-Part-1-Test-method-한글.pdf




I. Introduction

피로 및 파괴 시험은 Dynamic test로 분류되는 반복 하중을 가하는 시험으로서

Dynamic test로 분류되며 Fracture, Fatigue, Impact 시험이 포함.

Impact 시험은 반복하중은 아니지만 하중을 가하는 속도가 빠른 관계로 재료의 거동이

Dynamic test와 유사.

Fatigue test

Low cycle (LCF)

High cycle (HCF)

GIGA cycle 피로시험 (VHCF)

Fracture test

탄성거동에 기반한 KIC,

탄/소성 거동에 기반한 JIC, CTOD, J-R 시험

Paul C. Paris – Stress Intensity Factor Concept 1961

James Robert Rice – J Integral Concept 1968

Impact test

Pendulum type과 Drop weight type으로 분류

Pendulum type

충격방법에 따라 Charpy, Izod, Tension으로 분류

Drop weight type

목적에 따라 DWIT (Drop Weight Impact Test), DBTT(Ductile-Brittle Transition Temperature),

DWTT(Drop Weight Tear Test)로 명명





II. Fatigue Test

인장강도 이하의 반복적인 하중을 가하여 파괴하는 시험

재료의 내구성이나 반복하중에 대한 저항성을 측정하는 시험

Cycle에 따른 피로강도를 구하는 것이 주 목적

Low cycle (LCF) 및 High cycle (HCF)로 나뉘며 최근에는 GIGA cycle (VHCF)도 사용

▪ S-N선도

▪ 저주파 (Low-cycle) 및 고주파(High-cycle)피로: 105이상 고주파 피로.

▪ 고주파 피로: 탄성범위 이하의 응력

▪ 저주파 피로: 소성범위까지의 높은 Strain

▪ 피로시험 종류: Axial, Bending, Torsion, Complex loading,

Corrosion fatigue, Thermal fatigue

▪ Fatigue crack growth rate da/dN

▪ Fatigue crack growth threshold ΔKth

ASTM E466 Conducting Force Controlled Constant Amplitude Axial Fatigue Tests of Metallic Materials

ASTM E467 Verification of Constant Amplitude Dynamic Forces in an Axial Fatigue Testing System

ASTM E468 Presentation of Constant Amplitude Fatigue Test Results for Metallic Materials

ASTM E606 Strain-Controlled Fatigue Testing

ASTM E647 Measurement of Fatigue Crack Growth Rates

ASTM E1049 Practices for Cycle Counting in Fatigue Analysis

ASTM E1457 Measurement of Creep Crack Growth Times in Metals

ASTM E1823 Terminology Relating to Fatigue and Fracture Testing

ASTM E739 Statistical Analysis of Linear or Linearized Stress-Life (S-N) and Strain-Life (ε-N) Fatigue Data

ASTM B593 Bending Fatigue Testing for Copper Alloy Spring Materials

ASTM D7774 lexural Fatigue Properties of Plastics

ASTM E1823 Standard Terminology Relating to Fatigue and Fracture Testing

ASTM E1942 Evaluating Data Acquisition Systems Used in Cyclic Fatigue and Fracture Mechanics Testing

ASTM E2714 Standard-Test-Method-for-Creep-Fatigue-Testing

ASTM E466 Conducting Force Controlled Constant Amplitude Axial Fatigue Tests of Metallic Materials

ASTM E468 Constant Amplitude Fatigue Presentation of Constant Amplitude Fatigue Test Results for Metallic Materials

ASTM E606 Strain-Controlled Fatigue Testing

ASTM E647 Measurement of Fatigue Crack Growth Rates

ASTM E739 Statistical Analysis of Linear or Linearized Stress-Life (S-N) and Strain Life (ϵ-N) Fatigue Data

Fatigue Test Seminar

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ISO R 373:1964 General principles for fatigue testing of metals

ISO 1099 Fatigue testing axial force-controlled method

ISO 1143 Rotating bar bending fatigue testing

ISO 12106 Fatigue testing -Axial-strain-controlled method

ISO 12108 Fatigue testing -Fatigue crack growth method

ISO 12110-1 Fatigue testing -Variable amplitude fatigue testing Part 1: General principles, test method and

reporting requirements

ISO 12110-2 Fatigue testing -Variable amplitude fatigue testing Part 2: Cycle counting and related data

reduction methods

ISO 12111 Fatigue testing -Strain-controlled thermo-mechanical fatigue testing method

ISO 23788 Verification of the alignment of fatigue testing machines

Fatigue Test TIP

▪ Hourglass Shape 시편

▪ Surface scratch direction – Parallel to Loading Axis

▪ Undercut 제거가 어려운 경우 약간의 Hourglass 편법을 사용

▪ 표면조도는 길이 방향의 Scratch라면 영향이 적은 편

▪ Data rejection 기법이 중요

CHAUVENET’s Criterion

규정된 표준편차 기준

TN25 Statistical Analysis for Material Testing Data

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ΔK - da/dN Curve

여러 조건에 좌우되지 않은 재료 고유의 피로균열 진전 특성 표현을 위한 인자가 필요

선형 파괴역학 인자인 응력확대계수 K 도입 Paul C. Paris 교수

K 값은 균열 크기와 형상 외부 작용 하중에 의해서 결정

Crack이 존재하는 경우의 피로시험 결과는 ΔK와 da/dN관계로 표현

응력확대계수 범위, ΔK=Kmax-Kmin

균열진전 속도, da/dN

균열의 진전에 따라 ΔK 값은 점차적으로 증가

ΔKth Point에 상응하는 da/dN ~10-9~10-10m/cycle

세 단계 영역

영역 I

피로균열의 진전 속도가 매우 느린 영역

재료의 미세조직, 평균응력 환경요인이 균열 진전속도를 좌우

영역 II

응력확대계수 범위가 피로균열 진전에 가장 큰 영향

da/dN=C(ΔK)m Paris’ Law

m은 각 재료가 갖는 고유한 상수 값 (금속재료의 경우 m=2~4)

영역 III

균열의 증가에 따라 Kmax가 파괴 인성값, KC에 도달함에 따라 불안정한 파괴

피로하중을 받고 있는 구조물의 유지관리 측면에서 중요하게 이용되는 부분은 영역 II





III. Fracture Toughness Test

1961년 Dr. Paris의 Stress Intensity Factor, 1968년 Dr. Rice의 J Concept 도입

인성시험은 선형 파괴역학 기초로 한 Plain strain 조건인 응력확대계수, K

탄/소성 파괴역학 기초로 Plain stress 조건인 J 적분, COD(CTOD)

재료의 인성시험에는 충격시험도 사용하며 다양한 상황에서의 충격시험이 사용.

▪ 균열 존재 구조물의 파괴와 변형을 해석하는 파괴역학

▪ 균열 거동을 정량적으로 해석하기 위한 Parameter

▪ Stable Crack Extension 유무, Plane Strain Condition Criteria

▪ ModeⅠ(열림형), Mode II (내면전단형), ModeⅢ(내외전단형)

▪ Crack opening Mode, KIC, KIIC, KIIIC로 표시

Fracture Test TIP

▪ 어느 정도 소성 변형이 생길지 예측이 매우 중요

Plane strain condition 또는 Plane stress condition

▪ Fatigue crack tip의 Straightness가 시험 성패의 주 원인

용접부의 Residual stress 등

▪ 표면 조도는 길이 방향의 Scratch라면 영향이 적은 편

▪ Strength ratio R (1990년대)의 이용

Fracture와 Deform의 비교 척도로 사용

ASTM B909 Plane Strain Fracture Toughness Testing of Non-Stress Relived Aluminum Products

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ASTM C1421 Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature

ASTM D5045 Plane-Strain-Fracture-Toughness-and-Strain-Energy-Release Rate of Plastic Material

ASTM E1820 Measurement-of-Fracture-Toughness

ASTM E1921 Determination of Reference Temperature for Ferritic Steels in the Transition Range

ASTM E399 Linear Elastic Plane Strain Fracture Toughness KIC of Metallic Materials

ASTM E1221 Determining Plane Strain Crack Arrest Fracture Toughness KIa of Ferritic Steels

ASTM E1290 Crack Tip Opening Displacement (CTOD) Fracture Toughness Measurement

ASTM E1304 Plane-Strain Chevron Notch Fracture Toughness of Metallic Materials

ASTM E1681 Determining Threshold Stress Intensity Factor for Environment Assisted Cracking of Metallic Materials

ASTM E561 Standard Test Method for KR Curve Determination

ASTM E604 Dynamic Tear Testing of Metallic Materials

ASTM E740 Fracture Testing with Surface Crack Tension on Sepcimens

ASTM F2183 Standard Test Method for Small Punch Testing of Ultra-High Molecular Weight

Polyethylene Used in Surgical Implants

ISO 12135:2002, Unified method of test for the determination of quasi-static fracture toughness

KIC 시험

평면 변형률 파괴인성(Plane Strain Fracture Toughness), KIC 시험으로

소송변형이 거의 없이 파괴되는 경우 인성척도로 사용

▪ 탄성역학을 바탕으로 제안

▪ 소성변형이 거의 없이 파단이 일어나는 경우의 인성척도로 사용

▪ 임계 응력확대계수(Critical Stress Intensity Factor) KC

▪ 굽힘 시편과 Compact Tension CT시편

ASTM D5045 Standard Test Methods for Plane-Strain Fracture Toughness and Strain Energy Release Rate of

Plastic Materials

ASTM E399 Linear-Elastic Plane-Strain Fracture Toughness KIc of Metallic Materials

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JIC 시험

Plane Stress Fracture Toughness, JIC 시험

소성변형 후 파괴되는 재료의 인성척도로 사용.

▪ ASTM E813으로 제정 후 E1737로 개정을 통하여 ASTM E1820으로 통합

▪ 탄/소성 파괴인성을 사용한 JIC

▪ J-Integral은 균열길이의 변화에 따라 시편단위 두께당의 에너지 Release Rate

▪ J-Integral과 응력확대계수

▪ 실험적 방법으로 J 값을 구하는 것은 해석적인 방법에 비해 간단

▪ 하중-변위 곡선에서 균열 진전에 따른 탄성 및 소성 변형 에너지 값으로 J 측정

▪ 시편 Single Edge Bend (SEB) Disk Shaped Compact Tension (DCT) Compact Tension (CT)

▪ Fatigue Pre-cracking & Side Groove

▪ Crack Resistance Curve (J-R Curve)

▪ Single-specimen technique- Elastic compliance

▪ Multiple specimen technique - Extrapolation

ASATM E1820 Measurement of Fracture Toughness한글

ASTM E813-89 Test Method for JIC, A Measure of Fracture Toughness (Withdrawn 1997)

ASTM E1737-96 Test Method for J-Integral Characterization of Fracture Toughness (Withdrawn 1998)

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CTOD Test

실험 Data를 바탕으로 개발된 시험방법으로 주로 용접부 인성 척도로 사용.

▪ COD시험은 재질 선택, 용접법 평가, 결함 존재에 따른 안전성 평가에 사용

▪ COD (Crack Opening Displacement)

▪ CTOD (Crack Tip Opening Displacement)

▪ CTOA (Crack-Tip Opening Angle)

▪ 영국 1972년 예비규격 DD19로 규격화 후 1979년에 BS 5762

▪ 미국 ASTM E1290 CTOD

▪ 영국 BS 7448, 미국 ASTM E1820으로 변경

▪ ISO 12135, ISO 15653으로 제정

▪ BS와 ASTM의 CTOD 계산법의 차이로 인한 문제점이 상존

ASTM 계산식:

BS 계산식:

▪ ASTM으로 구한 CTOD 값이 BS로 보다 낮게 측정

▪ 과거 Data와의 관계를 고려하여 BS (또는 ISO)를 선호

ASTM E1290 Crack Tip Openning Displacement (CTOD) Fracture Toughness Measurement

Difference between ASTM E1290 and BS 7448 CTOD Estimation Procedures

BS 7448-2:1997 Fracture mechanics toughness tests. Method for determination of KIc, critical CTOD and critical

J values of welds in metallic materials

CTOD Standard Comparison

ISO 12135:2016 Unified method of test for the determination of quasi-static fracture toughness

ISO 15653:2010 Method of test for the determination of quasi-static fracture toughness of welds

BS 7448-1:1991 Fracture mechanics toughness tests. Method for determination of KIc, critical CTOD and critical

J values of metallic materials

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IV. Impact Test

반복하중은 아니지만 빠른 속도의 시험으로 동적 시험으로 분류.

Pendulum type 및 Drop weight type 사용.

Pendulum type은 충격방법에 따라 CHARPY, IZOD, TENSION으로 분류

Drop weight type은 목적에 따라 DWIT (Drop Weight Impact Test), DBTT(Ductile-Brittle

Transition Temperature), DWTT(Drop Weight Tear Test)로 명명

NDT (Nil- Ductility Transition) 및 DBTT(Ductile Brittle Transition Temp.) 측정

Instrumented Impact cell을 사용하여 시간에 따른 하중 및 Energy Plot

Pendulum Type Impact Test

▪ Pendulum swing 형식의 기기를 사용하여 규정된 시편의 파단에너지 측정

▪ 시편, 시편지지대, Striking tup, Moving mass, 에너지 측정 System 등으로 구성

▪ CHARPY, IZOD, TENSION type으로 구분

▪ 교정과 검사는 ASTM E23 준수

▪ 교정은 직접교정과 시편을 이용한 간접교정으로 구분

ASTM E23 Notched Bar Impact Testing of Metallic Materials

ISO 14556 Charpy V-notch pendulum impact test -- Instrumented test method

ASTM E1236 Qualifying Charpy Impact Machines as Reference Machines

ASTM D256 Determining The Izod Pendulum Impact Resistance of Plastics

ASTM D6110 Determining the Charpy Impact Resistance of Notched Specimens of Plastics

ISO 148-1 Metallic materials - Charpy pendulum impact test -Part 1 Test method

KS M ISO 179-2 플라스틱－샤르피 충격 강도의 측정－제2부：계장 충격 시험

KS M ISO 180 플라스틱－아이조드 충격강도의 측정

KS M ISO 3127 열가소성 플라스틱 관－ 외부 충격 저항의 측정－연속법

KS M ISO 6603-1 플라스틱-경질 플라스틱의 천공 충격거동의 측정- 제1부: 비계기식 충격시험

KS M ISO 6603-2 플라스틱-경질 플라스틱의 천공 충격거동의 측정-제2부: 계기식 충격시험

KS M ISO 7765-2 플라스틱 필름 및 시트- 다트 자유 낙하법에 의한 내충격성의 측정-

제2부: 계기식 천공 시험

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Drop Weight Type Impact Test

▪ 연성과 취성파괴 전이 온도 Nil Ductility Transition (NDT) 온도 결정에 사용

▪ 낙하시험에 의해 결정되는 파괴인성을 요구하는 다양한 경우에 사용

▪ 충격에너지는 재료에 따라 340~1630J 자유낙하 Weight 사용.

▪ 시편준비 및 온도조절 후 초기낙하시험은 NDT온도 근처 시험온도에서 시작

▪ 결과에 따라 후속시험은 적절한 온도간격으로 수행

▪ 파손 여부결정은 5°C 이내 한계로 설정

ASTM D3763 High Speed Puncture Properties of Plastics Using Load and Displacement Sensors 한글

ASTM E208 Conducting Drop Weight Test to Determine Nil Ductility Transition Temperature of Ferritic Steels 한글

ASTM E436 Drop Weight Tear Tests of Ferritic Steels 한글

ASTM E602 Sharp-Notch Tension Testing with Cylindrical Specimens 한글

GMW16086 2009 Evaluation for Susceptibility to Secondary Cold Work Embrittlement 한글

ASTM D7136 Measuring the Damage Resistance to impact

http://www.randb.co.kr/mailto:[email protected]://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-D3763-High-Speed-Puncture-Properties-of-Plastics-Using-Load-and-Displacement-Sensors한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E208-Conducting-Drop-Weight-Test-to-Determine-Nil-Ductility-Transition-Temperature-of-Ferritic-Steels한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E436-Drop-Weight-Tear-Tests-of-Ferritic-Steels-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E602-Sharp-Notch-Tension-Testing-with-Cylindrical-Specimens-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/GMW16086-2009-Evaluation-for-Susceptibility-to-Secondary-Cold-Work-Embrittlement한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ASTM-D7136-Measuring-the-Damage-Resistance-to-impact-한글.pdf




V. Small Punch Test

▪ 가동 중인 제품의 잔여수명평가를 위한 인성측정은 강도에 영향을 미치지 않는 범위에서

미소시편을 이용한 준비파괴적인 방법을 사용

▪ KIC 등과 같은 인성평가는 CT시편, 3점 굽힘 시편 등과 같이 상당히 재료가 필요하나

이렇게 큰 시편을 사용중인 부재로부터 채취는 사실상 거의 불가능.

▪ 이 중 가장 많이 사용되는 방법은 Disc시편을 사용하는 Small punch (SP)시험으로

현재 SP시험을 다루는 국제 표준은 없다

▪ 30년 이상 사용되었지만 Data에서 재료특성을 유도하는 합의절차는 아직 미완성.

▪ 일본 표준은 존재하지만 Creep test 에만 국한

미국 SP 표준은 외과 Implant에 사용되는 SP 시험 (ASTM F2183, ASTM F2977)

ASTM E 643은 볼 펀치 변형시험을 통해 금속판재 시험으로 SP시험과 유사.

▪ 최대 장점은 시편 크기가 소형 10mm×10mm × 0.5mm, 10mm×10mm×0.25mm 3mmΦ× 0.25mm (TEM disk)

SP 시편 허용오차 ±0.5mm 이내

SP 시편 표면상태 1500＃ Grinding ▪ Test Jig

10 mm 시편 경우- 2.4mm Φ (3/32인치) Steel Ball

3mmΦ 시편 경우 1mm Φ Steel ball Hardness HRC62~67

▪ Loading rate

Crosshead speed 0.1~1.0mm/min Standard speed 0.2mm/min.

ASTM F2183 Small Punch Testing of UHMWPE Used in Surgical Implants한글

ASTM F2977 Small Punch Testing of Polymeric Biomaterials Used in Surgical Implants

ASTM E643 Ball Punch Deformation of Metallic Sheet Material 한글

Recent developments in small punch testing 한글

Small punch 시험법

http://www.randb.co.kr/mailto:[email protected]://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-F2183-Small-punch한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2017/12/ASTM-F2977-13-Small-Punch-Testing-of-Polymeric-Biomaterials-Used-in-Surgical-Implants-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/ASTM-E643-Ball-Punch-Deformation-of-Metallic-Sheet-Material한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/Recent-developments-in-small-punch-testing-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2018/07/Small-punch-시험법.pdf




VI. Crack Tunneling

Fracture 및 Fatigue 시험 시 Pre-crack 조건의 시험이 많은 상황

Crack Tunneling은 균열 정면의 중간 단면에 Crack이 먼저 진행하고, 나머지 부분을 따라

균열 성장이 이어져 엄지 손톱 모양의 균열 프로파일이 형성

규격은 Crack Tunneling에 대한 엄격한 규제를 정하여 시험의 유효성을 제한

Fatigue crack을 요하는 피로파괴 시험의 성패는 Crack Tunneling 방지가 관건

Crack Tunneling 방지 방법 BS 7448-Part 2: Method for Determination of KIC, critical CTOD and critical J values of welds in metallic materials (1997) Annex D (normative) Residual stress modification and pre-cracking technique

▪ Local compression

Notch 아래 Ligament에 국부 압축을 가하면 잔류응력을 낮고 균일 수준으로 감소

시편 두께의 1 %까지 소성 변형

용접 후 열처리에 의해 응력이 완화된 용접부는 보통 국부 압축이 불필요 ▪ Reverse bending

피로 균열 전 가공된 Notch를 압축

Notch Root에서 재료를 소성 변형시켜 일정한 인장 잔류 응력을 유발 ▪ Stepwise high-R ratio

피로 균열 균열은 각기 다른 피로 응력 비 (R)의 두 단계로 구성.

제 1 단계, 피로균열이 대략 1 mm의 길이로 성장할 때까지 R = 0.1 사용

제 2 단계 R은 0.7로 증가하여 피로 균열을 원하는 길이로 증가 BS 7448 Part 2 Fracture mechanics toughness tests. Method for determination of KIc, critical CTOD and critical J

values of welds in metallic materials

Local compression에 의한 crack tunneling 방지법

Modelling of fatigue crack tunneling and delamination in layer composite

Reverse bending에 의한 crack tunneling 방지법

http://www.randb.co.kr/mailto:[email protected]://www.randb.co.kr/wp-content/uploads/2019/05/BS-7448-Part-2-1997-Fracture-mechanics-toughness-tests-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/BS-7448-Part-2-1997-Fracture-mechanics-toughness-tests-한글.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/Local-compression에-의한-crack-tunneling-방지법.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/Modelling-of-fatigue-crack-tunneling-and-delamination-in-layer-composite.pdfhttp://www.randb.co.kr/wp-content/uploads/2019/05/Reverse-bending에-의한-crack-tunneling-방지법.pdf




VII. Crack Measuring Method

Fracture와 Fatigue 시험의 Key Point 중 하나는 전파되는 Crack 길이의 측정

Crack 길이는 표면과 내부 차이로 광학적으로 측정하는 Crack 크기는 비합리

광학적 방법은 부수적인 방법

두께 전체의 평균 Crack 크기를 측정하는 방법이 선호

Direct 측정방법

▪ Microscope 방법

ASTM: 0.1mm의 간격 계측을 권장

▪ Crack gage 방법

Foil type gage를 시편에 부착하여 측정

▪ Replica 방법

Crack 형상을 복제하여 현미경으로 측정.

▪ DIC 방법 Digital Image Correlation

Indirect 측정방법

▪ Direct current potential drop (DCPD) Method

부식환경, 시험온도 그리고 전기적 Noise 발생 등 사용상의 제약

ASTM E 647 기반

금속시편에 일정 전류를 인가하고 시편 양단에서 전압강하 측정

시편에 전류를 흘리면 전기장이 시편 형상 및 균열 크기와 관계

Crack 증가에 따라 전압이 변하고 적절한 교정을 통하여 Crack 크기를 측정

전위차 대 균열크기의 상관관계는 각 시편의 형상에 따른 독자적인 관계식

▪ Compliance Method

ASTM E647 기반

Compliance: 탄성계수 및 시편두께에 대하여 표준화한 하중변위 곡선의 기울기 값의 역수

고속 디지털 처리 기술로 가장 많이 채용되고 있는 계측 방법

Strain energy release rate, G 값의 증가는 Compliance, C 값의 증가와 비례 G =(P2/2B) /(dC/da) Dimensionless Compliance vEB/P = f (a/W)

실험적으로 구한 Compliance C 값으로부터 피로 균열 길이 계산





R&B TEST ROPE Solution

고객 요구사항에 따른 System 개발

Multi Axis Tester

Axial Torsional System

High Frequency Durability Tester

▪ Imagination의 실체화

▪ Idea와 Concept을 설계

▪ 신뢰할 수 있는 구성요소 및 Software제공

▪ 경제적인 가격으로 효과적인 시험 System 구현

▪ 구성요소는 고객요구에 따라 기존 유명 Maker 부품 사용

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Application Field

▪ General Material & Machinery Field

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Process

▪ Information & Related Standards Review

▪ Structure & Software Design

▪ Confirm with FEM Analysis

▪ Components Selection

▪ Fabrication & Assembly

▪ Checkout

RB Test ROPE Brochure

R&B Information

RB Introduction

http://www.randb.co.kr/mailto:[email protected]://www.randb.co.kr/wp-content/uploads/2019/04/RB-Test-ROPE-Brochure1.pdfhttp://www.randb.co.kr/wp-content/uploads/2014/12/RB-Introduction.pdfhttp://www.randb.co.kr/wp-content/uploads/2014/12/RB-Introduction.pdf




Epilog

본 자료 준비에 참여하여 주신 많은 분들께 감사 드리며

실명을 공개할 수 없지만 ASTM 번역에 도움을 주신 여러 교수님 및 연구원님 들에게

지면으로나마 감사 드립니다.


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Documents

R&B Technical Note TN16 Fatigue & Fracture Toughness Test · 2020. 2. 18. · TN 16 Fatigue & Fracture Toughness Test , [email protected] 본 자료는 R&B Inc.의 자료로 무단