Development of Surface Roughness Generation Model for CFRTP Manufactured by LFT-D
Motoyuki Murashima*,, Takaharu Murooka**, Noritsugu Umehara*, and Takayuki Tokoroyama*
*Department of Micro-Nano Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University
Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
**Department of Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
In this study, we propose a new surface generation model for carbon fiber reinforced thermoplastics (CFRTP) manufactured by the long fiber thermoplastic-direct (LFT-D) method. CFRTP are considered to be a next-generation structural material because of their high productivity as well as high mechanical strength and lightness. Conversely, CFRTP have a rough surface, which does not meet the automotive outer panel standard of a “class A surface.” In the present study, we establish a surface roughness generation model based on a thermal shrinkage mismatch of thermoplastic resin to carbon fiber and non-uniform carbon fiber distribution. Furthermore, we construct a surface roughness estimation formula based on the model. In the calculation, a cross-sectional image of CFRTP is divided into many vertical segments. Subsequently, the thermal shrinkage of each segment is calculated with a standard deviation, an average, and a probability density of the amount of carbon fiber in each segment. The surface roughness of the manufactured CFRTP was measured using a surface profilometer. The result showed that the arithmetic surface roughness increased with the volume fraction of carbon fiber. We applied the surface roughness calculation to cross-sectional images of the specimens. Consequently, the estimated surface roughness showed the same tendency, in which the surface roughness increased with the volume fraction of carbon fiber. The slope of a regression line of the estimated surface roughness with respect to the volume fraction was 0.010, which was almost the same (0.011) as the slope of a regression line of the measured surface roughness. Furthermore, the estimation formula using a thermal shrinkage effective depth of 395 μm was able to estimate the surface roughness within a 3% average error. Using the estimation formula, it was predicted that the surface roughness increased with the standard deviation of the amount of carbon fiber in a segment. To confirm the reliability of the model and the formula, we measured the standard deviation of the amount of carbon fiber in CFRTP specimens, showing that the trend for CFRTP specimens matched the estimated values.
-  M. Yamane, “Thermoplastic CFRP technology collection, Tribology of diamond-like carbon films: recent progress and future prospects,” Science & Technology Co., Ltd., 2015 (in Japanese).
-  R. Sawaoka et al., “CFRP/CFRTP no kakougijutu to seinouhyouka (2nd edition),” S&T Publishing inc., 2012 (in Japanese).
-  C. Soutis, “Carbon fiber reinforced plastics in aircraft construction,” Mat. Sci. Eng. A, Vol.412, Issues 1-2, pp. 171-176, 2005.
-  C. Soutis, “Fibre reinforced composites in aircraft construction,” Progress in Aerospace Sci., Vol.41, Issue 2, pp. 143-151, 2005.
-  A. Kitano, “Characteristics of Carbon-Fiber-Reinforced Plastics (CFRP) and Associated Challenges – Focusing on Carbon-Fiber-reinforced Thermosetting Resins (CFRTS) for Aircraft,” Int. J. Automation Technol., Vol.10, No.3, pp. 300-309, 2016.
-  Y. Kurihara, “The role of aluminum in automotive weight reduction – Part I,” JOM, Vol.45, Issue 11, pp. 32-33, 1993.
-  M. K. Kulekci, “Magnesium and its alloys applications in automotive industry,” Int. J. Adv. Manuf. Technol., Vol.39, Issues 9-10, pp. 851-865, 2008.
-  Europe Union, “Regulation (EU) No 333/2014 of the European parliament and of the council,” Official J. of the European Union, pp. L103/15-L103/21, 2014.
-  H. Helms and U. Lambrecht, “The potential contribution of light-weighting to reduce transport energy consumption,” Int. J. Life Cycle Assess., Vol.12, No.1, pp. 1-7, 2007.
-  Y. Kurihara, “The role of aluminum in automotive weight reduction – Part II,” JOM, Vol.46, Issue 2, pp. 33-35,1994.
-  L. W. Cheah, “Cars on a diet: The material and energy impacts of passenger vehicle weight reduction in the U.S.,” Ph.D. thesis in Engineering Systems, Massachusetts Institute of Technology, pp. 1-121, 2010.
-  W. Krause, F. Henning, S. Tröster, O. Geiger, and P. Eyerer, “LFT-D – A process technology for large scale production of fiber reinforced thermoplastic components,” J. Thermoplastic Comp. Mat., Vol.16, No.4, pp. 289-302, 2003.
-  F. Henning, H. Ernst, R. Brussel, O. Geiger, and W. Krause, “LFTs for automotive applications,” REINFORCED Plastics, Vol.49, Issue 2, pp. 24-33, 2005.
-  O. Geiger, F. Henning, P. Eyerer, R. Brussel, and H. Ernst, “LFT-D: materials tailored for new applications,” Reinforced Plastics, Vol.50, No.1, pp. 30-35, 2006.
-  M. Schemme, “LFT – development status and perspectives,” Reinforced Plastics, Vol.52, Issue 1, pp. 38-43, 2008.
-  F. W. J. van Hattum, J. P. Nunes, and C. A. Bernardo, “A theoretical and experimental study of new towpreg-based long fibre thermoplastic composites,” Composites Part A: Applied Science and Manufacturing, Vol.36, Issue 1, pp. 25-32, 2005.
-  J. Markarian, “Long fibre reinforced thermoplastics continue growth in automotive,” Plastics, Additives and Compounding, Vol.9, Issue 2, pp. 20-22, 24, 2007.
-  R. Hsakou, “Curvature: the relevant criterion for Class A surface quality,” JEC Composites Magazine, No.43, pp. 105-108, 2006.
-  N. Boyard, C. Serré, and M. Vayer, “A Physical Approach to Define a Class A Surface in Polymer Thermosetting Composite Materials,” J. Appl. Polymer Sci., Vol.103, No.1, pp. 451-461, 2007.
-  T. Kikutani and K. Takemura, “Illustration: Plastic mold material,” Morikita Publishing Co., Ltd., pp. 74-81, 2011 (in Japanese).
-  T. Kyono and K. Takahashi, “Theoretical Investigation of the Thermal Expansion Coefficients of Unidirectional Carbon Fiber Composites,” J. Soc. Mat. Sci., Vol.38, Issue 426, pp. 307-311, 1989 (in Japanese).
-  R. Puffr and V. Kubánek, “Lactam-based Polyamides Volume II Modification, Technology and Application,” CRC Press, pp. 187-188, 1991.
-  Japanese Industrial Standards, JIS B 0601:2013, “Geometrical Product Specifications (GPS) – Surface texture: Profile method – Terms, definitions and surface texture parameters,” 2013.
-  http://www.kenkai.jaxa.jp/research/pastres/cfrp.html [Accessed July 28, 2019]
-  T. Kamiya, S. Utsunomiya, K. Komatsu, and R. Shimizu, “Improvement of the CFRP composite mirror surface using a replica method,” Proc. of 18th Int. Conf. on composite Mat., pp. 1-6, 2011.
-  T. Yoneyama, D. Tatsuno, K. Kawamoto, and M. Okamoto, “Effect of press slide speed and stroke on cup forming using a plain-woven carbon fiber thermoplastic composite sheet,” Int. J. Automation Technol., Vol.10, No.3, pp. 381-391, 2016.
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