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Mechanical analysis of three dimensional textile composites using fiber-based continuum model : 섬유기반 연속체 모델을 이용한 삼차원 텍스타일 복합재료의 역학적 해석

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dc.contributor.advisor유웅열-
dc.contributor.author안현철-
dc.date.accessioned2017-07-13T05:49:07Z-
dc.date.available2017-07-13T05:49:07Z-
dc.date.issued2016-02-
dc.identifier.other000000132217-
dc.identifier.urihttps://hdl.handle.net/10371/118044-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 재료공학부, 2016. 2. 유웅열.-
dc.description.abstractFiber reinforced polymer composites are widely used in industrial field, such as military, aerospace and automobile, and in the spotlight of using structural materials. For this reason, mechanical analysis and manufacturing process composites are researched in numerus studies. Moreover, many structural analysis of composites are published for improving its properties and reinforcing its properties. Unit cell approach is major concept of mechanical analysis of composite and three dimensional (3D) modelling of composite structure is well established. This unit cell analysis has high accuracy and reflecting complicated composite structures, however it has high cost of computing time and modeling process. Moreover it cannot be considered structural effect from deformation and loading condition. For this reason, new approach of composite mechanical analysis is developed with continuum based model in this study. The aim of this method is continuum analysis with fast computing time and considering structural effect of textile composite structures with one-step 3D structural analysis.

New numerical analysis model, called fiber based continuum model (FBM), is continuum based algorithm considered fiber orientation and structure of a textile composite. Fiber architecture is important factor of mechanical properties of a composite, so FBM is focused on fiber structure and its change inside of a composite. Moreover, this method is used fiber and matrix properties for numerical analysis, so structural analysis can be done with minimum parameters. Furthermore, based on layer method and modified ply discount method, Failure behavior can be predicted with Pucks failure citation.

3D textile composite fabrication and structure analysis method are developed for numerical validation and characterization, in the next chapter. FBM analysis can be used for arbitrary 3D textile composites with yarn path function, so verification works is needed with several 3D structures. In this study, 3D five axis braided and orthogonal woven composite is manufactured and tested. For this, 3D weaving method was developed in laboratory scale. Moreover, before the mechanical test of composites, structural analysis is done with micro-CT image.

Finally, FBM is verified with experimental of 3D textile composites. Tensile and bending test was done for characterization of composites. The experimental results of which were compared with simulated results, demonstrating that the current numerical model can properly predict the mechanical behavior of 3D fiber-reinforced composites. Moreover, based on FBM analysis, application of 3D textile composite is investigated.
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dc.description.tableofcontentsChapter 1. Introduction 1
1.1 Fiber reinforced polymer composites (FRPs) 1
1.2 Mechanical behavior prediction of FRPs 3
1.2.1 Composite stiffness prediction theories 3
1.2.2 Failure criterion of FRPs 8
1.3 Research objectives 19

Chapter 2. Fiber based continuum model (FBM) 21
2.1 Fiber based analysis mechanism 21
2.2 Numerical approach 22
2.2.1 Methodology of mechanical prediction of FRPs 22
2.2.2 Algorithm of update yarn pattern 23
2.2.3 Stiffness calculation of FRPs 24
2.2.4 Strength prediction and damage propagation 30
2.2.5 Stress update and processing increment 33
2.3 Characterization and validation of the model 34
2.3.1 Model characterization 34
2.3.2 Verification of mechanical properties prediction 40
2.3.3 3D structure calculation 42
2.4 Summary 43

Chapter 3. Fabrication and modelling of 3D textile composites 44
3.1 3D braided structures 44
3.1.1 Fabrication of 3D five-axis braided preforms 44
3.1.2 Unit cell and fiber based continuum modelling 46
3.2 3D orthogonal woven structures 50
3.2.1 Fabrication of 3D orthogonal woven preforms 50
3.2.2 Unit cell and fiber based continuum modelling 53
3.3 Forming and characterization of 3D textile composites 56
3.3.1 Vacuum assisted resin transfer molding (VARTM) process 56
3.3.2 Structure and material properties characterization 58
3.4 Summary 61

Chapter 4. Mechanical analysis of 3D textile composites 63
4.1 Experimental 64
4.1.1 Tensile test of 3D composites 64
4.1.2 Bending test of 3D composites 65
4.2 Theoretical analysis 66
4.2.1 Simulation procedure and boundary condition 67
4.2.2 Result treatment and post calculation 68
4.3 Results and discussions 70
4.3.1 Experimental results 70
4.3.2 Numerical results and comparison 76
4.3.3 Discussions and applications 85
4.4 Summary 89

Chapter 5. Concluding remarks 90

References 93

Korean Abstract 101
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dc.formatapplication/pdf-
dc.format.extent3647419 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectfiber-reinforced composites-
dc.subjectnumerical analysis-
dc.subjectstructural analysis-
dc.subject3D composites-
dc.subjectfiber based model-
dc.subject.ddc620-
dc.titleMechanical analysis of three dimensional textile composites using fiber-based continuum model-
dc.title.alternative섬유기반 연속체 모델을 이용한 삼차원 텍스타일 복합재료의 역학적 해석-
dc.typeThesis-
dc.contributor.AlternativeAuthorHyunchul Ahn-
dc.description.degreeDoctor-
dc.citation.pagesvii, 102-
dc.contributor.affiliation공과대학 재료공학부-
dc.date.awarded2016-02-
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