Pseudo-ductile behavior of glass/carbon fiber hybrid composite with carbon/epoxy platelets

摘要

Composite materials have been developed over the years as a way to eliminate the weight issues that come along with the conventional use of metals. Composite materials have become a priority material when light weight is an issue of consideration and also high strengths are required. Although they have this advantage over metals they also luck other important properties that comes with metal which still makes metal superior. Many developments have been made on composite to try and mimic the metal properties and hybrid composites came up. By this type of composite they take the best of different properties and combining them into one. This is because different composites share different properties with these metals so if combined together they share these properties in a consolidated material thus bringing properties that resembles the metal properties. Further engineering aspects have been injected into these hybrid composites to try and improve the properties that come with them. This can be done by altering different aspects of the composite through calculations of different parameters of the material constituents of the composite. In this thesis, the behavior of a hybrid composite which contains two composites will be studied, one is the low elongation carbon epoxy composite and the other is the high elongation glass epoxy composite laminate. The property that is to be studied is the pseudo-ductility in composite whereby it is the creating of a plastic region normally observed in the stress strain curves of metals. There are several engineered advancements that have been made in different hybrids that are geared towards bringing this effect of which includes using a very thin layer of carbon in glass, the use of short thin carbon platelets and also making a highly dispersed hybrid of glass with carbon fibers. In this hybrid composite, these two engineering aspects of the thin carbon ply and carbon platelets will be combined, and then tensile tests carried out to observe properties of pseudo-ductility. The first chapter is the topic motive, the problem statement, justification, objectives of this study and scope of the research will be stated in details.
　　The second chapter the literature review is studied to do a background check on what has been done in the research area. Since the topic deals with a new property that is to be built into composites, less researches have been done on it. This means there is still a lot of modification which can be made on this topic with proper funding since acquiring this kind of thin carbon fiber prepreg is difficult and more expensive. On the third chapter materials and methodology will be discussed. Materials acquisition will be explained of which the materials include, E-glass of 0.125mm prepreg and thin carbon prepregs of 0.03mm thickness. Properties will also be mentioned. Here detailed information will be given on the sample designs, geometric features, which will be followed by an explanation on how the samples were prepared. All the instruments and equipment used in the sample preparations and their testing, are mentioned with their images here. The fourth chapter the test results will be given, of which they are the respective stress strain curves of the sample designs and a table giving the values of the sample properties for specific properties. In this chapter also there will be a discussion of the results obtained in this study and the discussion will be done in four subtopics, whereby the first, pseudo-ductility will be discussed for the samples that had this property, the second is the tensile strength of the samples, the third is the elastic modulus relationship observed and finally a detailed discussion on the finite element analysis (FEA) that was carried out on some of the samples, one sample representing a pseudo-ductile sample and the other representing a catastrophically failed sample. The fifth chapter the conclusion on the study that was carried out is given, and finally the sixth and final chapter are the references giving all the information of the citations used in this study.

目录

致谢

声明

LIST OF ABBREVIATIONS

CHAPTER 1. INTRODUCTION

1.1 Problem statement

1.2 Justification

1.3 Objectives

1.4 Study area

1.5 Limitations of the study

1.6 Scope of research

CHAPTER 2. LITERATURE REVIEW

2.1 Composite materials

2.2 Pseudo-ductility

2.3 FEA damage models

CHAPTER 3. EXPERIMENTAL AND SIMULATION

3.1 Materials and sample design

3.2 Specimen preparation

3.3 Testing

3.4 Finite element analysis (FEA)

CHAPTER 4. RESULTS AND DISCUSSION

4.1 E-Glass with 50%resin content Carbon fiber Prepreg

4.2 E-Glass with 41.1%resin content Carbon fiber Prepreg

4.3 Finite element Analysis (FEA)

CHAPTER 5. CONCLUSION

参考文献