Practical Acoustic Emission Testing (eBook)

Editor in Chief: Yoshihiro Mizutani, Tokyo Institute of Technology, Assoc. Prof., Tokyo, JAPANEditors: Hidehiro Inaba, Fuji Ceramics Corporation Hideyuki Nakamura, IHI Inspection & Instrumentation Co., Ltd. Manabu Enoki, University of Tokyo Masaaki Nakano, Chiyoda Advanced Solutions Mitsuhiro Shigeishi, Kumamoto University Shigenori Yuyama, Nippon Physical Acoustics, Ltd. Shinji Takeda, Japan Aerospace Exploration Agency Tomoki Shiotani, Kyoto University Yoshihiro Mizutani, Tokyo Institute of TechnologyAuthors: Hidehiro Inaba, Fuji Ceramics Corporation Hideyuki Nakamura, IHI Inspection & Instrumentation Co., Ltd. Manabu Enoki, University of Tokyo Masaaki Nakano, Chiyoda Advanced Solutions Masayasu Ohtsu, Kumamoto University Mitsuhiro Shigeishi, Kumamoto University Shigenori Yuyama, Nippon Physical Acoustics, Ltd. Sunao Sugimoto, Japan Aerospace Exploration Agency Tomoki Shiotani, Kyoto University Yoshihiro Mizutani, Tokyo Institute of Technology

Preface 6
Opening Figures 8
1. Applications 8
2. Monitoring Systems and Software 13
Contents 14
List of Contributors 16
Chapter 1: Roles and Safety/Health of Technicians Involved in Non-destructive Testing 17
1.1 Importance of Non-destructive Testing 17
1.2 Role of a Level 1 Technician as Specified by ISO9712 18
1.2.1 Duties Acknowledged for NDT Level 1 Technicians 18
1.2.2 Responsibilities of Level 1 Technicians 18
1.3 Health and Safety for NDT Technicians 19
1.3.1 Caution in Equipment Handling 19
1.3.2 Work at High Elevations 19
1.3.3 Prevention of Explosions 20
Chapter 2: Principles of the Acoustic Emission (AE) Method and Signal Processing 21
2.1 Principles of the AE Method 21
2.2 AE Testing as Non-destructive Testing 25
2.3 Types and Characteristics of AE Sources 26
Description of Term (Transformation) 27
2.4 Properties of AE Waves 29
2.4.1 Propagation in Solids 29
2.4.2 Wave Velocity and Wavelength 30
2.4.3 Attenuation 31
2.4.4 Reflection and Transmission 32
2.5 Signal Processing 36
2.5.1 What Is an AE Signal? 36
2.5.2 Basics of Waveform Parameters 37
2.5.3 Discrimination of an AE Signal 38
2.5.4 AE Parameters 42
2.6 AE Source Location 45
2.6.1 One-Dimensional and Two-Dimensional Location Methods 45
2.6.2 Guard Sensor 47
2.6.3 Zone Location 48
2.6.4 Leak Location 50
Chapter 3: AE Sensor (AE Transducer) 51
3.1 Conversion Mechanism 51
3.2 Types and Structures of AE Sensors 53
3.2.1 Resonance and Broad-Band Sensors 53
3.2.2 Structure 54
3.3 Characteristics of AE Sensors 54
3.4 Various Specifications of AE Sensors 56
3.4.1 Insulation (Surface for Installation) 56
3.4.2 Waterproofness 56
3.4.3 Signal Output Method 57
3.4.4 Cable (Low-Noise Cable) 58
3.4.5 Integrated Preamplifier Sensor 58
3.5 Calibration of AE Sensors 58
Chapter 4: AE Measurement System 60
4.1 Configuration of an AE Measuring Instrument 60
4.1.1 Basic Configuration of the AE Measurement System 61
4.1.2 Preamplifier 62
4.1.2.1 Input/Output Types 63
4.1.2.2 Gain (Amplification Ratio) 64
Description of Term (dB (Decibel)) 64
4.1.2.3 Frequency Response 65
4.1.2.4 Noise 65
Description of Term (SN Ratio) 66
4.1.2.5 Input/Output Impedance 66
Description of Term (Impedance) 66
4.1.2.6 Power Supply 67
4.1.2.7 Dimensions/Shape/Weight and Environmental Resistance 67
4.1.3 Main Amplifier 68
4.1.4 Signal Processor (AE Parameter Extraction Circuit) 68
4.1.5 Output/Display Device (Computer for Measurements) 69
4.2 Peripheral Equipment 71
4.2.1 Oscilloscope 71
4.2.2 Spectrum Analyzer 71
4.2.3 Pulse Generator (Pulsar) 71
4.2.4 Audio Monitor 72
4.2.5 Instrument for Measurements of External Parameters and Environmental Conditions 72
4.3 Connection Cable and Connector 73
4.3.1 Cable Between an AE Sensor and Preamplifier 73
4.3.2 Connection Cable Between a Preamplifier and Main Amplifier 73
4.3.3 Other Connection Cable 74
Chapter 5: Practical AE Testing, Data Recording and Analysis 76
5.1 Preparation for AE Testing and Sensitivity Check of the AE Measurement Instrument 76
5.1.1 Setup of the Instrument 77
5.1.1.1 Installation of the Instrument 77
5.1.1.2 Connection of the Instrument 78
5.1.1.3 Connection of Signal Cables 78
5.1.1.4 Setting of Measurement Conditions 78
5.1.1.5 Setup of the Monitor Display 82
5.1.2 Installation of an AE Sensor 82
5.1.2.1 Selection of Position for Sensor Installation 82
5.1.2.2 Pretreatment of the Surface Where a Sensor Will Be Installed 83
5.1.2.3 Method for the Mechanical Installation of a Sensor 84
5.1.2.4 Method for Attaching a Sensor with Adhesives 85
5.1.2.5 Waveguide 86
5.1.2.6 Connection of a Preamplifier 86
5.1.3 Sensitivity Check of an AE Sensor 87
5.1.3.1 Review of the Overall Connection Status 87
5.1.3.2 Sensitivity Check by Pencil Lead Break 87
5.1.3.3 Sensitivity Check by a Pulse Generator 88
5.2 Noise 89
5.2.1 Types of Noise 90
5.2.1.1 Acoustic Noise 90
5.2.1.2 Electric Noise 91
5.2.2 Preventive Measures and Countermeasures Against Generated Noise 91
5.2.2.1 Electric Noise 91
5.2.3 Identification of the Noise Source 93
5.3 Test Methods 93
5.3.1 Loading Method 93
5.3.1.1 Material Evaluation Test 93
5.3.1.2 AE Testing of Structure 95
5.3.2 Data Sampling of External Analog Parameters 96
5.3.3 Data Display 97
5.4 Evaluation of Measurement Data and Test Recordings 102
5.4.1 Interpretation and Evaluation of Measurement Data 102
5.4.1.1 Test Conditions 102
5.4.1.2 Evaluation of Data Series 103
5.4.1.3 Evaluation of Correlations Among AE Parameters 105
5.4.1.4 Evaluation of Frequency in AE Parameters 106
5.4.1.5 Evaluation Based on AE Source Locations 107
5.4.1.6 Criteria for Structural Integrity in AE Testing 110
5.4.2 Records of AE Testing 112
5.4.2.1 Items Relating to the Test Environment 113
5.4.2.2 Items Relating to Test Pieces/Specimens 113
5.4.2.3 AE Sensors 113
5.4.2.4 Installation of AE Sensor 113
5.4.2.5 AE Measurement 113
5.4.2.6 Setting of peripheral devices 114
5.4.2.7 AE Measurement Environment 114
5.4.2.8 Recording and Reporting of Test Results 114
Chapter 6: Field Application Examples of AE Testing 115
6.1 Large Pressure Vessel 115
6.1.1 AE Testing Method 116
6.1.2 Results of AE Testing 116
6.2 Pipelines 118
6.3 High-Pressure Gas Storage Bottle 121
6.4 Above Ground Storage Tank 121
6.5 Leak Detection 124
6.6 Transformer 124
6.7 Railway Bridges 126
6.8 Stability Monitoring of a Rock Slope 128
6.9 Initial Ground Stress 129
6.10 Aircraft 131
Glossary 134
Precautions 134
Appendix: List of Codes and Standards 138
Introduction 138
Codes and Standards 138
Index 141