A numerical study on the thermal expansion coefficients of fiber

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57 Figure 5.4 A representative meshed unit cell having a fiber volume fraction equal to 68%. Mesh refinement is performed until the changes in the results are sufficiently small. A representative meshed unit cell having 12678 elements and 19046 nodes is shown in Figure 5.4, and the mesh on the fiber matrix interface is shown in Figure 5.5. Figure 5.5 The finite element mesh on the fiber matrix interface for fiber volume fraction of 68%. 5.3 Material Properties The constituent property data used in the analyses are given in Tables 5.1, 5.2, and 5.3. The data in Table 5.1 is taken from the investigation of Sideridis (1994). The unidirectional glass fiber composites used in his investigation consisted of an epoxy matrix (permaglass XE5/1, Permali Ltd, UK) reinforced with long E-glass fibers having a diameter of 0.012 mm. The properties of transversely isotropic carbon fibers and other isotropic matrix materials are taken from the <strong>study</strong> of Bowles and Tompkins (1989). The constituent properties used in their analyses are given in Table 5.2 and 5.3. Some of these data was experimentally measured values and were taken from various literature sources which include both research papers and manufacturers’ product data sheets. However, many of the transverse fiber properties represent values that were calculated from composite properties. T300 and C6000
58 carbon fibers were assumed to have same properties. All of the epoxies were assumed to have same properties except CE339, which has a larger CTE. This larger value of CTE is due to the rubber particles in this rubber toughened epoxy. Table 5.1 Material properties, at room temperature, used for the composite consisting of isotropic glass fibers and isotropic epoxy matrix (Sideridis, 1994). Material E (GPa) G (GPa) ν α (10 -6 /ºC) Epoxy 3.5 3.89 0.35 52.5 Glass fiber 72 40 0.2 5 Table 5.2 Matrix properties at room temperature (Bowles, & Tompkins, 1989). Matris E (GPa) G (GPa) ν α (10 -6 /ºC) 934 epoxy 4.35 1.59 0.37 43.92 5208 epoxy 4.35 1.59 0.37 43.92 930 epoxy 4.35 1.59 0.37 43.92 CE339 epoxy 4.35 1.59 0.37 63.36 PMR15 polymide 3.45 1.31 0.35 36 2024 Aluminum 73.11 27.58 0.33 23.22 Borosilicate glass 62.76 26.20 0.20 3.24 Table 5.3 Carbon fiber properties at room temperature (Bowles, & Tompkins, 1989). Fiber E 1 (GPa) E 2 (GPa) G 1 (GPa) G 2 (GPa) ν 1 ν 2 α 1 (10 -6 /ºC) α 2 (10 -6 /ºC) T300 233.13 23.11 8.97 8.28 0.2 0.4 − 0.54 10.08 C6000 233.13 23.11 8.97 8.28 0.2 0.4 − 0.54 10.08 HMS 379.35 6.21 7.59 2.21 0.2 0.4 − 0.99 6.84 P75 550.40 9.52 6.9 3.38 0.2 0.4 − 1.35 6.84 P100 796.63 7.24 6.9 2.62 0.2 0.4 − 1.40 6.84
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DOKUZ EYLÜL UNIVERSITY GRADUATE SC
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M.Sc THESIS EXAMINATION RESULT FORM
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A NUMERICAL STUDY ON THE THERMAL EX
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CONTENTS Page THESIS EXAMINATION RE
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4.2.1 Geometry Creation............
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2 coefficients of thermal expansion
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4 coefficients coincide to give res
Page 15 and 16: 6 concentration from pure metal to
Page 17 and 18: 8 high strength-to-weight and stiff
Page 19 and 20: 10 polymers. Thermosetting polymers
Page 21 and 22: 12 Metals are strong and tough. The
Page 23 and 24: 14 Table 2.1 Properties of reinforc
Page 25 and 26: 16 2.2.2.2 Carbon Fibers Carbon is
Page 27 and 28: 18 use is in aircraft industry foll
Page 29 and 30: 20 strength and a reasonable Young
Page 31 and 32: 22 1. Processing the conventional f
Page 33 and 34: 24 (orthorhombic) of polyethylene h
Page 35 and 36: 26 Whiskers are monocrystalline sho
Page 37 and 38: 28 3.2 Factors Affecting the Coeffi
Page 39 and 40: 30 3.2.4 Thermal Cycling The primar
Page 41 and 42: 32 3.3.1 Mechanical Dilatometry Thi
Page 43 and 44: 34 absolute accuracy of about ± 0.
Page 45 and 46: 36 3.3.3 Strain Gauges This relativ
Page 47 and 48: 38 • The composite is macroscopic
Page 49 and 50: 40 3.4.1.3 Equation of Van Fo Fy In
Page 51 and 52: 42 and the thermal expansion coeffi
Page 53 and 54: 44 P P 11 33 2 A 22 − A = Det A A
Page 55 and 56: 46 • A perfect bonding exists at
Page 57 and 58: CHAPTER FOUR FINITE ELEMENT METHOD
Page 59 and 60: 50 No matter how the geometry is cr
Page 61 and 62: 52 displacements and/or rotations a
Page 63 and 64: CHAPTER FIVE MICROMECHANICAL ANALYS
Page 65: 56 5.2 Mesh Creation 10-node tetrah
Page 69 and 70: 60 Figure 5.6 The displacement fiel
Page 71 and 72: 62 small differences between these
Page 73 and 74: 64 Table 6.1 Comparison of the expe
Page 75 and 76: 66 Longitudinal CTE (1/°C) 2.25E-0
Page 83 and 84: 74 Ishikava, T., Koyama, K., & Koba
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A numerical study on the thermal expansion coefficients of fiber

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