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Repair of Aircraft Structures Using Composite Patches Bonded Through Induction Heating
유도가열을 통한 항공기 구조물 복합재 패치 접착수리

DC Field Value Language
dc.contributor.advisor이우일-
dc.contributor.author김민호-
dc.date.accessioned2017-07-13T06:11:56Z-
dc.date.available2017-07-13T06:11:56Z-
dc.date.issued2014-02-
dc.identifier.other000000016568-
dc.identifier.urihttps://hdl.handle.net/10371/118346-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 기계항공공학부, 2014. 2. 이우일.-
dc.description.abstractWith the increasing aging aircraft, many unanticipated structural defects have been occurred in aircraft. Accordingly, many aircraft structural repair methods have been developed, but we need efficient method except for conventional repair method as mechanical riveting. This paper presents research on composite patch repair to damaged aluminum aircraft structure. Composite patches, bonded on cracked or corroded metallic aircraft structures, have shown to be a highly cost effective method for extending the service life and maintaining high structural efficiency. An aluminum double lap joint plate was considered as a damaged aircraft structural element in this paper. We repaired the plate with carbon fiber epoxy composite patch by induction curing, and by oven curing method. We also repaired it by precured composite patch bonding method, and by cocured composite patch bonding method. Then, the bond strengths were compared among different processing methods. The technique of electromagnetic induction is able to locally and rapidly heat the area close to the adhesive bond line. This allows for the efficient repair of the metallic substrate of aircraft, and may hence be regarded as a more efficient process. Induction heating constitutes an ideal candidate for supplying the heat needed for curing adhesives and resins, which are used for the fabrication of reinforcing patches, either on the flat, or over geometrically complex surfaces. We had conducted the experiment and numerical simulation to show that the induction curing was efficient repair heat sources in repairing metallic substrate of aircraft. We also investigated whether the incorporation of carbon nanotubes (CNTs) in the adhesive bondline affected bond strength.
We found that the induction-cured samples exhibited bond strengths similar to those of the corresponding oven-cured samples
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dc.description.abstractthis was true for both the baseline and the CNT-reinforced samples. Further, the samples processed using cocured patches exhibited higher bond strengths than did the corresponding samples processed using precured patches. In the case of both the precured and the cocured patch samples, the dispersion of 0.5 wt% CNTs in the adhesive bondline increased bond strength slightly. The effect of the two different types of patches placed on top of the aluminum substrate on the rate of temperature increase by induction curing was shown experimentally. And, numerical simulations were performed in case of the precured patch and un-cured patch on top of the aluminum substrate. The results from this study show that the induction curing and cocuring method may be regarded as a sound and efficient method for composite patch bonding repair.-
dc.description.tableofcontentsAbstract
Contents
List of Figures
List of Tables
Nomenclature

CHAPTER 1. INTRODUCTION

1.1 Overview and problem description
1.2 Literature review
1.2.1 Composite patch repair and CNT reinforcement
1.2.2 Curing with induction heating
1.3 Research objective and scope

CHAPTER 2. BACKGROUND AND THEORY

2.1 Management of aging aircraft
2.1.1 Overview of aging aircraft
2.1.2 Metallic corrosion
2.1.3 Structural fatigue
2.1.4 Maintenance of aging aircraft in Air Force
2.1.5 Repairing of aircraft at ABDR
2.2 Overview of patch repair
2.2.1 Properties of patching technology
2.2.2 Double-lap joint
2.3 Overview of induction heating
2.3.1 Theory of heating by induction
2.3.2 Resistance
2.3.3 Alternating current and electromagnetism
2.3.4 Hysteresis
Figures
Tables

CHAPTER 3. EXPERIMENT

3.1 Introduction
3.2 Experimental preparation
3.2.1 Specimen schematic and materials
3.2.2 DSC analysis of film adhesives used in experiment
3.2.2.1 Thermo chemical analysis
3.2.2.2 Cure-kinetics model
3.3 Experimental procedure and equipment
3.3.1 Surfaces preparation
3.3.2 Baseline sample
3.3.3 CNT reinforced sample
3.3.3.1 Dispersion process
3.3.3.2 Lay up procedure
3.3.4 Curing procedures
3.3.4.1 Oven curing
3.3.4.2 Induction curing
3.3.5 Bond strength measurement
3.4 Bond strength results and discussion
3.4.1 Baseline sample
3.4.2 CNT reinforced sample
3.4.3 Fracture surface of sample
3.4.4 Effect of co-curing procedures
3.4.4.1 Bondline profile
3.4.4.2 Bondline profile analysis
3.4.4.3 Deliberately patterned patch
3.4.4.4 FT-IR analysis of bondline interface
3.5 Fracture simulation of sample
3.5.1 Theory and model
3.5.2 Simulation process and results
3.6 Advantages of induction heating
3.6.1 Simulation of temperature rise rate
3.6.2 Results of simulation
Figures
Tables

CHAPTER 4. NUMERICAL ANALYSIS OF INDUCTION HEATING

4.1 Overview
4.2 Experiment of induction heating
4.2.1 Effect of patch for induction heating
4.2.2 Results of experiment
4.3 Numerical analysis
4.3.1 Modeling method for induction heating
4.3.1.1 Theoretical backgrounds
4.3.1.2 Mathematical modeling of the electromagnetic field
4.3.1.3 Mathematical modeling of the thermal processes
4.3.2 Simulation process
4.3.3 Results of simulation
4.3.3.1 Only aluminum substrates model
4.3.3.2 Precured patch on aluminum substrates model
4.3.3.3 Uncured patch on aluminum substrates model
4.4 Results and discussion
Figures
Tables

CHAPTER 5. SUMMARY AND CONCLUSIONS

References
Abstract (In Korean)
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dc.formatapplication/pdf-
dc.format.extent12395036 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subject.ddc621-
dc.titleRepair of Aircraft Structures Using Composite Patches Bonded Through Induction Heating-
dc.title.alternative유도가열을 통한 항공기 구조물 복합재 패치 접착수리-
dc.typeThesis-
dc.description.degreeDoctor-
dc.citation.pages116-
dc.contributor.affiliation공과대학 기계항공공학부-
dc.date.awarded2014-02-
Appears in Collections:
College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Mechanical Aerospace Engineering (기계항공공학부)Theses (Ph.D. / Sc.D._기계항공공학부)
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