Vibration and Impedance-based Hybrid Damage Detection Method for Wind Turbine Tower Structures
- Abstract
- In recent years, the wind energy has played an increasingly important role in national energy sector of many countries. To harvest more electric power, the wind turbine tower (WTT) structure becomes physically larger, which may cause more risks during its operation. To ensure the safety and the serviceability of the WTT structures, a structural health monitoring (SHM) system is needed. The objective of this study is to develop a vibration and impedance-based hybrid damage detection method for wind-turbine tower (WTT) structures. To achieve the objective, the following approaches will be implemented. Firstly, existing damage detection or monitoring practices for WTT structures are reviewed to justify the need of a hybrid damage detection method. Secondly, a hybrid damage detection scheme which combines vibration-based and impedance-based methods is developed for the WTT structures. Finally, the feasibility and performance of the hybrid damage detection method are experimentally evaluated for lab-scaled WTT models.
- Issued Date
- 2016
- Awarded Date
- 2016. 8
- Type
- Dissertation
- Keyword
- Vibration-based method Impedance-based method Wind Turbine Tower Structures Hybrid damage detection method
- Publisher
- 부경대학교 대학원
- Affiliation
- 부경대학교 대학원
- Department
- 대학원 해양공학과
- Advisor
- 김정태
- Table Of Contents
- CHAPTER 1 INTRODUCTION 1
1.1 Background 1
1.2 Objective and Scope 4
1.3 Organization of the Thesis 5
CHAPTER 2 DAMAGE DETECTION METHODS 6
2.1 Introduction 6
2.2 Vibration-based Damage Detection Method 6
2.2.1 Frequency-based Damage Detection Method 7
2.2.2 Mode shape-based Damage Detection Method 8
2.3 Impedance-based Damage Detection Method 9
2.3.1 Electro-mechanical Impedance Theory 9
2.3.2 Impedance-based Damage Detection Approaches 12
2.4 Feasibility Verification of Damage Detection Method 13
2.4.1 Feasibility Verification of Vibration-based Method 13
2.4.2 Feasibility Verification of Impedance-based Method 17
CHAPTER 3 HYBIRD DAMAGE DETECTION SYSTEM FOR WIND TURBINE TOWER STRUCTURES 19
3.1 Introduction 19
3.2 Design of Hybrid Damage Detection Scheme for WTT Structures 19
3.3 Experimental Setup 21
3.3.1 Description of Target Structure 21
3.3.2 Test Setup 22
3.3.3 Damage Scenarios 24
3.4 Vibration-based Damage Occurrence Alarming for WTT Structures 24
3.4.1 Acceleration Responses 24
3.4.2 Frequency-response-ratio Assurance Criterion 25
3.4.3 Modal Parameter Extraction Approaches 29
3.5 Impedance-based Damage Localization for WTT Structures 30
3.5.1 Electro-mechanical Impedance Responses 30
3.5.2 Impedance-based Damage Localization 32
3.6 Frequency-based Damage Estimation 34
3.6.1 Damage Location Estimation 35
3.6.2 Damage Severity Estimation 44
3.7 Wind Speed Effects on Vibration Modal Parameters 45
CHAPTER 4 DAMAGE PREDICTION ACCURACY OF HYBRID DAMAGE DETECTION SCHEME 52
4.1 Introduction 52
4.2 Sensitivity Analysis of Vibration Modes 52
4.2.1 Sensitivity Investigation for FBDD Method 52
4.2.2 Sensitivity Investigation for MBDD Method 59
4.3 Damage Prediction Accuracy of Vibration-based Algorithms with Two Modal Parameter Extraction Methods 66
4.3.1 Evaluation of Damage Prediction Accuracy using FBDD 67
4.3.2 Evaluation of Damage Prediction Accuracy using MBDD 68
4.4 Evaluation of Hybrid Vibration-Impedance Method under Limited Measurement Data 72
CHAPTER 5 CONCLUSIONS 82
REFERENCE 84
- Degree
- Master
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