TOOLED THICK COMPOSITES by ARVEN H. SAUNDERS III ...

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ABSTRACT PROCESS MODELING SYSTEM FOR PRESS CURE, CLOSED-CAVITY- Supervising Professor: Don Liles TOOLED THICK COMPOSITES Arven H. Saunders, III, PhD The University of Texas at Arlington, 2011 Thick structural composite parts often use press curing with closed-cavity tooling for achieving dimensional tolerances. A commonly encountered defect for these parts is fiber waviness, which limits its structural strength. The yield for such parts often suffers due to trial and error methods used to develop successful cure processes. In addition, yield for these parts suffers due to material variation. The objectives that were accomplished through this research were to: develop and validate a simplified yet practical cure process model for press cured thick composite parts, utilize the model in order to seek time-efficient optimized cure processes, investigate the effects of material variation on optimized cure processes, and to utilize the model to investigate the origins of fiber waviness. The model was found to indicate the conditions under which it is likely that fiber waviness occurs. iv
TABLE OF CONTENTS ACKNOWLEDGEMENTS ........................................................................................... ……………..iii ABSTRACT ..................................................................................................................................... iv LIST OF ILLUSTRATIONS............................................................................................................. viii LIST OF TABLES ............................................................................................................................. x Chapter Page 1. INTRODUCTION……………………………………..………..….. .................................... .1 1.1 Background ..................................................................................................... .1 1.2 The Nature of the Problem .............................................................................. .3 1.3 Problem Statement ......................................................................................... .5 1.4 Objectives of Research ................................................................................... .6 2. REVIEW OF RELATED RESEARCH AND LITERATURE ............................................ 7 2.1 Cure Process Overview ................................................................................... 7 2.2 Uniqueness of Thick Composites.................................................................... .8 2.3 Cure Cycle Development ............................................................................... 10 2.4 Temperature and Resin Cure Reactions ...................................................... .11 2.5 Resin State and Viscosity Changes .............................................................. .13 2.6 Pressure and Laminate Consolidation .......................................................... .13 2.6.1 Consolidation Models ..................................................................... 14 2.7 Improved Approaches To Cure Process Optimization .................................. .14 2.8 Material And Process Variability Effects On Optimal Cure Cycles ............... .18 2.9 Conclusions and Dissertation Approach ....................................................... .19 v
Page 1 and 2: PROCESS MODELING SYSTEM FOR PRESS C
Page 3: ACKNOWLEDGEMENTS This dissertation
Page 7 and 8: 4. RESULTS ........................
Page 9 and 10: 4.7 Acceptable IM7/3501-6 Flexbeam
Page 11 and 12: CHAPTER 1 INTRODUCTION 1.1 Backgrou
Page 13 and 14: Inspection and evaluation technique
Page 15 and 16: Figure 1.3. Fiber/Layer Waviness in
Page 17 and 18: CHAPTER 2 REVIEW OF RELATED RESEARC
Page 19 and 20: greatly lag in temperature. As a re
Page 21 and 22: Physics-based models are often used
Page 23 and 24: equation above can be solved by wri
Page 25 and 26: keep the cure on track. Examples of
Page 27 and 28: (Chen, 2002). However, because they
Page 29 and 30: during cure and consolidation. In a
Page 31 and 32: initially in the cure process but w
Page 33 and 34: Figure 3.1. Generic Flexbeam with T
Page 35 and 36: Permeability describes the resistan
Page 37 and 38: patterns velocity and timing during
Page 39 and 40: S ii 2 f r = 4k ii ( 1− V where r
Page 41 and 42: proportion of the applied pressure
Page 43 and 44: At any timestep in the simulation,
Page 45 and 46: constant displacement ramp followed
Page 47 and 48: 6 5 4 3 2 1 0 Figure 3.8. Model Con
Page 49 and 50: decrease for CVs that were previous
Page 51 and 52: total resin volume rate for the lam
Page 53 and 54: series electrical circuits—a left
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hold these values, with R(k) being
Page 57 and 58:
• Resin pressure causes resin flo
Page 59 and 60:
where α is cure, An is the pre-exp
Page 61 and 62:
temperature conditions. The princip
Page 63 and 64:
cycle. The ability to optimize temp
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Temperature (C) 200 180 160 140 120
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Temperature (C) 200 180 160 140 120
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useful; as pointed out by Cirisciol
Page 71 and 72:
Flexbeam (z) Height and Tool Lid Po
Page 73 and 74:
55 minutes into the S2/8552 cycle,
Page 75 and 76:
Resin Pressure (Pa) 1.2E+06 1.0E+06
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-7.138E-12 -7.138E-12 -6.517E-12 -5
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keeping the level below a certain t
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feedback to set the temperature cur
Page 83 and 84:
(Chen, 2002) Chen, Y., "Modeling of
Page 85 and 86:
(Mitra, 2009) Mitra, K., Majumder,
Page 87 and 88:
(Walia, 2006) Walia, R., Shan, H.,
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TOOLED THICK COMPOSITES by ARVEN H. SAUNDERS III ...

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