infrared thermography and ultrasonic inspection of adhesive bonded structures, overview and validity

101 Pages·2016·3.16 MB·English

Clemson University
TigerPrints
All Theses Theses
8-2010
INFRARED THERMOGRAPHY AND
ULTRASONIC INSPECTION OF ADHESIVE
BONDED STRUCTURES, OVERVIEW AND
VALIDITY
Suhas Vedula
Clemson University, [email protected]
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Recommended Citation
Vedula, Suhas, "INFRARED THERMOGRAPHY AND ULTRASONIC INSPECTION OF ADHESIVE BONDED
STRUCTURES, OVERVIEW AND VALIDITY" (2010).All Theses. 890.
https://tigerprints.clemson.edu/all_theses/890
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INFRARED THERMOGRAPHY AND ULTRASONIC INSPECTION OF ADHESIVE
BONDED STRUCTURES, OVERVIEW AND VALIDITY

A Thesis
Presented to
the Graduate School of
Clemson University

In Partial Fulfillment
of the Requirements for the Degree
Master of Science
Mechanical Engineering

by
Suhas Vedula
August 2010

Accepted by:
Dr. Mohammed Omar, Committee Chair
Dr. Pierluigi Pisu
Dr. Stephen Hung
ABSTRACT

The work focuses on establishing a relationship between two different techniques
of Nondestructive testing, namely Infrared Thermography and Ultrasonic Inspection. The
integration of the two testing techniques is done with an expectation to achieve accurate
characterization and determination of internal defects in adhesive bonded structures.
Experiments are done on sandwich samples with defects using various ultrasonic
testing methods like pulse-echo and immersion techniques. The results thus obtained are
documented and location of the defects is marked. The same samples are then tested
using Infrared thermography to visualize the defects.
The results obtained by both the methods are compared to check for accuracy of
the methods to detect and characterize the defects.
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DEDICATIO(cid:12)

This Thesis is dedicated to my parents Mr. Ranjan Vedula and Mrs. Kamala
Vedula. And to all those who have been supportive and motivating throughout.
iii
ACK(cid:12)OWLEDGME(cid:12)TS

I would like to acknowledge Dr. Mohammed Omar for his support during this
work. I would like to thank Dr. Pierluigi Pisu and Dr. Steve Hung for their valuable
suggestions and comments.
I would also like to thank my friends Konda Reddy, Bhanu, Singh, Sree Harsha
Pamidi, Rohit Parvataneni, Yi Zhou, Qin Shen and Ahmad Mayyas for their help in
conducting the experiments and in my thesis review.

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TABLE OF CO(cid:12)TE(cid:12)TS

Page

TITLE PAGE .................................................................................................................. i

ABSTRACT ..................................................................................................................... ii

DEDICATION ................................................................................................................ iii

ACKNOWLEDGMENTS .............................................................................................. iv

LIST OF TABLES ........................................................................................................ viii

LIST OF FIGURES ........................................................................................................ ix

CHAPTER 1
ADHESIVE BONDED STRUCTURES THEORY AND APPLICATION ...................... 1
1.1 INTRODUCTION TO ADHESIVE BONDING ...................................................... 1
1.2 FUNCTION OF ADHESIVES/SEALANTS ............................................................ 1
1.3 CLASSIFICATION OF ADHESIVES/SEALANTS................................................ 2
1.4 APPLICATION OF ADHESIVES BONDED JOINTS IN THE AUTOMOBILE .. 9
1.5 SANDWICH MATERIALS ................................................................................... 12
1.6 ADVANTAGES AND DISADVANTAGES OF ADHESIVE BONDING .......... 15
1.7 GENERAL COMPARISON OF COMPETITIVE METAL JOINING PROCESSES
WITH ADHESIVE BONDING .................................................................................... 17
CHAPTER 2
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NONDESTRUCTIVE TESTING OF ADHESIVE BONDED JOINTS .......................... 19
2.1 INTRODUCTION ................................................................................................... 19
2.2 ULTRASONIC TESTING ...................................................................................... 21
2.3 TRANSIENT THERMOGRAPHY ........................................................................ 30
2.4 SHEAROGRAPHY ................................................................................................ 31
2.5 X-RAY RADIOGRAPHY ...................................................................................... 33
2.6 BETA RAY BACKSCATTER ............................................................................... 34
2.7 RESONANT INSPECTION ................................................................................... 35
2.8 RADIOACTIVE TRACER ..................................................................................... 36
CHAPTER 3
INFRARED THERMOGRAPHY .................................................................................... 37
3.1 INTRODUCTION ................................................................................................... 37
3.2 THERMOGRAPHY TECHNIQUES ..................................................................... 38
3.3 THERMAL IMAGING ........................................................................................... 47
3.4 THERMAL PROPERTIES OF THE SAMPLE ..................................................... 49
3.5 APPLICATIONS OF THERMOGRAPHY ............................................................ 50
3.6 ADVANTAGES AND LIMITATIONS OF THERMOGRAPHY ......................... 54
CHAPTER 4
ULTRASONIC PULSE ECHO METHOD ...................................................................... 55
4.1 INTRODUCTION ................................................................................................... 55
vi
4.2 BASIC PRINCIPLE ................................................................................................ 56
4.3 TRANSDUCER SELECTION ............................................................................... 59
4.4 MATERIAL PROPERTIES OF THE SAMPLE .................................................... 62
4.5 ADVANTAGES OF ULTRASONIC TESTING ................................................... 65
4.6 LIMITATIONS OF ULTRASONIC TESTING ..................................................... 65
4.7 APPLICATIONS OF ULTRASONICS .................................................................. 66
CHAPTER 5
LABORATORY TESTS AND RESULTS ...................................................................... 68
5.1 TEST SPECIMEN................................................................................................... 68
5.3 LABORATORY EQUIPMENT ............................................................................. 69
5.4 LABORATORY EXPERIMENTS AND RESULTS ............................................. 74
CHAPTER 6
CONCLUSION AND FUTURE WORK ......................................................................... 85
REFFERENCES: .............................................................................................................. 86

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LIST OF TABLES

Table Page
Table 1.1 Mechanical applications of adhesives .......................................................... 10
Table 1.2 Body shop applications of adhesives ........................................................... 11
Table 1.3 General comparison of joining processes
with adhesive bonding ................................................................................. 18
Table 5.1 Transducer specifications............................................................................. 70
Table 5.2 Specifications and images of Infrared cameras
used in the experiments ................................................................................ 72
Table 5.3 Flash heating source specifications .............................................................. 73
Table 5.4 Halogen heating source specifications ......................................................... 73
Table 5.5 Induction heating source specifications ....................................................... 73
Table 5.6 Thermography test results for steel sample of
0.5 mm plate thickness ................................................................................ 81
Table 5.7 Thermography test results for steel sample of
1 mm plate thickness .................................................................................... 82
Table 5.8 Thermography test results for steel sample of
3 mm plate thickness .................................................................................... 83
Table 5.9 Thermography test results for steel sample of
5 mm plate thickness .................................................................................... 84
viii
LIST OF FIGURES
Figure Page

Figure 2.1 Pitch-catch inspection methods ................................................................. 22
Figure 2.2 MIA inspection method ............................................................................. 25
Figure 2.3 Spring mode............................................................................................... 26
Figure 2.4 Resonant standing wave over a disbonded joint........................................ 28
Figure 2.5 Multi layered disband tests ........................................................................ 28
Figure 2.6 Through transmission technique................................................................ 29
Figure 2.7 Basic Thermography experimental setup .................................................. 31
Figure 2.8 Basic Shearography setup.......................................................................... 33
Figure 2.9 X-Ray Radiography setup ......................................................................... 33
Figure 3.1 Thermography setup .................................................................................. 38
Figure 3.2 Classification of Thermography testing methods ...................................... 39
Figure 4.1 Pulse Echo testing method of an adhesive joint ........................................ 56
(a) Experimental setup ............................................................................... 56
(b) Wave path vs Time ............................................................................... 56
(c) Amplitudes of A-Scan echoes .............................................................. 56
Figure 4.2 Inspection of steel adhesive bonded joint;
Steel (0.8mm); Adhesive (0.5mm)............................................................ 57
Figure 4.3 A- Scan images of the adhesive joint ........................................................ 58
Figure 5.1 Steel sample of 5mm thickness ................................................................. 68
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