在射出成形製程中，多數產品之幾何變得越來越複雜，使熔膠在模穴中的流動行為變得難以預測，若是再添加纖維至熔膠中更難以了解纖維結構在模穴內的流動行為，其流變性質會因為材料性質與加工條件等等而有所不同。因此，本研究希望藉由使用模流分析軟體Moldex3D，並且利用具有漸縮漸張幾何之拉伸試片，進一步去了解到幾何在射出成形製程中對於纖維補強結構之影響性，且在此模擬過程中，更可以了解到纖維補強結構從流道至模穴中演變的歷程。除此之外，為了驗證在此幾何與數學模型的假設下結果是否符合真實情況，模擬結果將與擁有相同幾何模型之文獻作為對照。最終模擬結果顯示纖維排向會因為幾何改變而變化，並且纖維亦會因流道的幾何改變而發生斷裂，藉由改變充填時間，纖維排向、纖維長度以及纖維濃度結構因流場變化而改變，除此之外，在與文獻驗證其纖維排向及纖維長度後，模擬結果與文獻結果趨勢一致。

Lightweight technologies have been applied in many industries, especially in the automotive industry to enhance fuel efficiency. One of popular methods is applying fiber-reinforced thermoplastics (FRT) to enhance lightweight technologies. However, the reinforced mechanism of the fiber microstructures in FRT is still too complicated to be understood. The purpose of this research is to use the ASTM D638 with a dog-bond system to study the fiber microstructures in a FRT part. Results showed that the geometry of the cavity had significant effects on the fiber orientation during the injection molding processes. Due to the contraction and expansion structure, the orientation tensor component corresponding to the flow direction would be enhanced and weakened from gate region to end-of-flow region. Moreover, the breakage of fiber could be found at the corner of the runner section by using numerical visualization on the core layer from runner to cavity. By increasing the filling time, fiber orientation, fiber length and fiber concentration changed. Finally, the calculated fiber orientation and fiber length results were verified by results from the literature. Comparison between experiment results from the literature and numerical simulation, and both fiber orientation and length distribution matched.

[1] 張榮語, Ed. 射出成形模具設計-操作實務 (CAE-MOLD系列叢書). 高立圖書有限公司, 1998.
[2] D. V. Rosato and M. G. Rosato, Injection molding handbook. Springer Science & Business Media, 2012.
[3] S. G. Advani and E. M. Sozer, Process modeling in composites manufacturing. CRC Press, 2002.
[4] S. Kenig, "Fiber orientation development in molding of polymer composites," Polymer composites, vol. 7, no. 1, pp. 50-55, 1986.
[5] S. Goris, U. Gandhi, Y. Y. Song, and T. A. Osswald, "Analysis of the process-induced microstructure in injection molding of long glass fiber-reinforced thermoplastics." in ANTEC 2016 Conference Proceedings, 2016.
[6] R. Von Turkovich and L. Erwin, "Fiber fracture in reinforced thermoplastic processing," Polymer Engineering & Science, vol. 23, no. 13, pp. 743-749, 1983.
[7] L. Mondy, H. Brenner, S. Altobelli, J. Abbott, and A. Graham, "Shear‐induced particle migration in suspensions of rods," Journal of Rheology, vol. 38, no. 2, pp. 444-452, 1994.
[8] G. B. Jeffery, "The motion of ellipsoidal particles immersed in a viscous fluid," in Proceedings of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, vol. 102, no. 715, pp. 161-179, 1922.
[9] J. Ericksen, "Theory of anisotropic fluids," Transactions of the Society of Rheology, vol. 4, no. 1, pp. 29-39, 1960.
[10] G. L. Hand, "A theory of anisotropic fluids," Journal of Fluid Mechanics, vol. 13, no. 01, pp. 33-46, 1962.
[11] G. Batchelor, "Slender-body theory for particles of arbitrary cross-section in Stokes flow," Journal of Fluid Mechanics, vol. 44, no. 03, pp. 419-440, 1970.
[12] R. Cox and H. Brenner, "The rheology of a suspension of particles in a Newtonian fluid," Chemical Engineering Science, vol. 26, no. 1, pp. 65-93, 1971.
[13] E. Hinch and L. Leal, "Constitutive equations in suspension mechanics. Part 1. General formulation," Journal of Fluid Mechanics, vol. 71, no. 03, pp. 481-495, 1975.
[14] F. Folgar and C. L. Tucker III, "Orientation behavior of fibers in concentrated suspensions," Journal of reinforced plastics and composites, vol. 3, no. 2, pp. 98-119, 1984.
[15] S. G. Advani and C. L. Tucker III, "The use of tensors to describe and predict fiber orientation in short fiber composites," Journal of Rheology, vol. 31, no. 8, pp. 751-784, 1987.
[16] S. G. Advani and C. L. Tucker III, "Closure approximations for three‐dimensional structure tensors," Journal of Rheology, vol. 34, no. 3, pp. 367-386, 1990.
[17] H. M. Huynh, Improved fiber orientation predictions for injection-molded composites. 2001.
[18] J. Wang, J. F. O’Gara, and C. L. Tucker III, "An objective model for slow orientation kinetics in concentrated fiber suspensions: Theory and rheological evidence," Journal of Rheology, vol. 52, no. 5, pp. 1179-1200, 2008.
[19] J. H. Phelps, "Processing-microstructure models for short-and long-fiber thermoplastic composites," ProQuest, 2009.
[20] H.-C. Tseng, R.-Y. Chang, and C.-H. Hsu, "Phenomenological improvements to predictive models of fiber orientation in concentrated suspensions," Journal of Rheology, vol. 57, no. 6, pp. 1597-1631, 2013.
[21] S. M. Dinh and R. C. Armstrong, "A rheological equation of state for semiconcentrated fiber suspensions," Journal of Rheology, vol. 28, no. 3, pp. 207-227, 1984.
[22] J. H. Phelps, A. I. A. El-Rahman, V. Kunc, and C. L. Tucker III, "A model for fiber length attrition in injection-molded long-fiber composites," Composites Part A: Applied Science and Manufacturing, vol. 51, pp. 11-21, 2013.
[23] J. F. Morris and F. Boulay, "Curvilinear flows of noncolloidal suspensions: The role of normal stresses," Journal of rheology, vol. 43, no. 5, pp. 1213-1237, 1999.
[24] H. Potente, H. Schulte, and N. Effen, "Simulation of injection molding and comparison with experimental values," International Polymer Processing, vol. 8, no. 3, pp. 224-235, 1993.
[25] J. Vlcek, L. Miller, C. Huang, and M. Zatloukal, "Simulation of Screws for Injection Molding," in AIP Conference Proceedings, vol. 1152, no. 1, pp. 277-283, 2009.
[26] R. Y. Chang and W. H. Yang, "Numerical simulation of mold filling in injection molding using a three‐dimensional finite volume approach," International journal for numerical methods in fluids, vol. 37, no. 2, pp. 125-148, 2001.
[27] M. Cross, "Relation between viscoelasticity and shear-thinning behaviour in liquids," Rheologica Acta, vol. 18, no. 5, pp. 609-614, 1979.
[28] R. Y. Chang and S. Y. Chiou, "A unified K‐BKZ model for residual stress analysis of injection molded three‐dimensional thin shapes," Polymer Engineering & Science, vol. 35, no. 22, pp. 1733-1747, 1995.
[29] D. V. Krevelen, "Properties of polymers: their correlation with chemical structure: their numerical estimation and prediction from additive group contributions," 1990.
[30] T.-M. Su, Y.-C. Liu, C.-T. Huang, and D. Hsu, "Product Design Optimization through Seamless Integration of CAD and CAE," Computer-Aided Design and Applications, vol. 9, no. 4, pp. 471-479, 2012.
[31] Mesh Database, CoreTech System, Hsinchu, Taiwan.
[32] E. Lafranche, P. Krawczak, J. Ciolczyk, and J. Maugey, "Injection moulding of long glass fibre reinforced polyamide 6-6: guidelines to improve flexural properties," Express Polymer Letters, vol. 1, no. 7, pp. 456-466, 2007.
[33] M. Akay and D. Barkley, "Fibre orientation and mechanical behaviour in reinforced thermoplastic injection mouldings," Journal of materials science, vol. 26, no. 10, pp. 2731-2742, 1991.
[34] T. Papthanasiou and D. C. Guell, Flow-induced alignment in composite materials. Elsevier, 1997.
[35] J. O'Gara, P. Foss, and J. Harris, "Reinforced plastic design: microstructure and stiffness of tensile bars," in ANTEC 2001 Conference Proceedings, 2001.
[36] 郭茂松, "塑膠射出成形機的螺旋桿與料管."
[37] V. Yang, C. Huang, P. Tsai, J. Perdikoulias, and J. Vlcek, "Simulating the melting behavior and melt temperature inhomogeneity in the injection molding processes," in ANTEC 2004 Conference Proceedings, 2004