声明
摘要
Abstract
Table of Contents
Chapter 1．Introduction
1．1 Motivation
1．2 The definition of spot weld
1．3 Previous Work in Evaluation spot weld
1．3．1 Destructive testing method
1．3．2 Non-destructive testing method
1．4 Theoretical objectives
Chapter 2．Basic Principles of air-coupled guided waves testing spot welds
2．1 The definition of guided waves
2．2 Impedance mismatch
2．3 Leaky guided wave
2．4 Boundary condition between air and solid plate
2．5 Air coupled ultrasonic guided wave to detect spot welds
Chapter 3．Simulations
3．1 Introduction of simulation software
3．2 Parameter selection in Multiphysics COMSOL
3．3 Geometries of simulation models
3．4 Simulation the influence of different factors
3．4．1．Intensity at different incidence angles
3．4．2 Transducer-plate air gap reflections
3．4．3 Distance between sender and receiver
3．4．4 Different position of transducers
3．5 Simulation to inspect spot weld
3．5．1 Detection spot weld with 280kHz unfocused transducer
3．5．2 Detection spot weld with 500kHz focused transducer
Chapter 4．Experiments
4．1 Experiment set-up
4．2 Validation the influence of different parameters
4．2．1 Intensity at different incidence angles
4．2．2 Transducer-plate air gap reflections
4．2．3 The influence of distance between transducers
4．2．4 The influence of transducers position
4．3 Validation the simulation result when inspecting spot weld
4．3．1 Detection spot weld with 280kHz unfocused transducer
4．3．2 Detection spot weld with 500kHz focused transducer
4．4 Comparison between simulation and experiment
General Conclusion
Recommendations for Future Research
Acknowledgements
References
攻读硕士学位期间发表的论文及科研成果
