S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Material Science and Engineering (재료공학부) Theses (Ph.D. / Sc.D._재료공학부)
Mechanical analysis of three dimensional textile composites using fiber-based continuum model
섬유기반 연속체 모델을 이용한 삼차원 텍스타일 복합재료의 역학적 해석
- 공과대학 재료공학부
- Issue Date
- 서울대학교 대학원
- fiber-reinforced composites; numerical analysis; structural analysis; 3D composites; fiber based model
- 학위논문 (박사)-- 서울대학교 대학원 : 재료공학부, 2016. 2. 유웅열.
- Fiber 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 Puck’s 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.