Y. Gong, Z-G. Yang/Composites: Part B 53(2013)103-111 Fig. 13. SEM micrographs of other areas away from the stress concentration corner (a, b)pulled-out glass fibers perpendicular to the fracture surfaces, and (c, d) long and polypropylene) fibers as less as possible: (2)adequately adjusting References the process parameters to improve the distribution and alignment of the glass fibers, such as decreasing the injection pressure to pro- [1] Brady P. Brady motive composites: which way are we going? Reinf long the retention time inside the mold for the melt, and/ or mp A, Adam F, Krahl M, et al the mold perature and or the plastici uring concept for crash resistant textile a ture; (3)adequately decrease the localized size of the mold near the joint between the pedal and the frame, for increasing the thick [3 Hufenbach W. Bohm R, Thieme M, winkler A, et al. Polypropylene/glass fibre ness, i.e. enhancing the strength of the joint. The feedback from the 3D-textile reinforced composites for automotive applications. Mater Des pedal arm manufacturer after adopting these suggestions proved 14] Yang ZG, Gong Y, Yuan Jz Failure analysis of leakage on titanium tubes within all of them were effective wer plant. Part 1: Electrochemical corrosion. [5] Gong Y, Yang ZG, Yuan Jz Failure analysis of leakage on titanium tubes within 5 Conclusions corrosion on carbon heat exchanger of ethylene plant. Mater Corros 1:62(10):967-78. basically qualified. However, the defects like uneven distribu- 7 Gong at na diz ed resio ea aiten De s ne tion of the glass ate alis ment of analysis of bursting on the inner pipe of a fibers, and introduction of foreign organic fibers still existe tubula with a not light extent. [9] Gong Y, Cao g XH, Yang ZG. Pitting corrosion on 316L pipes in 2. As for the actual failed pedal arm, those defects coincidentally [101 Rjeb A, Tajounte L Chafik l Idrissi M. et ectroscopy study of occurred together on the stress concentration corner of the joint polypropylene natural aging. J Appl Polym Sci 2000: 77: 1742-8. between the pedal and the frame, so it fractured rather quickly [11 Abu-lsa L Thermal degradation of thin hims of when under the loads far lower than the designed value polypropylene with ketonic additives. J Polym Sci Pol Chem 1970: 8: 961-72 ared determination of the crystallinity of polypropylene. J 3. Based on the analysis results, countermeasures encompassing Polym Sci Pol Chem 1959: 38(134): 545-7. improvement of GF/PP pellets, adjustment of process parame- 13 Luongo JP ters, and tiny modification of the mold structure, etc was pro- andbook of fire protection engineering. Quincy (MA, USA): National Fire posed, and was proved to be effective by the pedal arm manufacturer afterwards the decomposition mechanism of [16] Lu QS, Sun LH, Yang ZG, Li XH, et al. Optimization on the thermal and tensile 1171 Su Acknowledgement contents on tensile properties of PTFE and attapulgite reinforced fabric composites Compos Part A: Appl Sci Manuf 2009: 40: 1785-91 The work was supported by Shanghai Leading Academic disci- pline Project(Project Number: B113)polypropylene) fibers as less as possible; (2) adequately adjusting the process parameters to improve the distribution and alignment of the glass fibers, such as decreasing the injection pressure to pro￾long the retention time inside the mold for the melt, and/or increasing the mold temperature and/or the plasticizing tempera￾ture; (3) adequately decrease the localized size of the mold near the joint between the pedal and the frame, for increasing the thick￾ness, i.e. enhancing the strength of the joint. The feedback from the pedal arm manufacturer after adopting these suggestions proved all of them were effective. 5. Conclusions 1. Properties of the pedal arms, even of the GF/PP pellets were basically qualified. However, the defects like uneven distribu￾tion of the glass fibers, inappropriate alignment of most glass fibers, and introduction of foreign organic fibers still existed with a not light extent. 2. As for the actual failed pedal arm, those defects coincidentally occurred together on the stress concentration corner of the joint between the pedal and the frame, so it fractured rather quickly when under the loads far lower than the designed value. 3. Based on the analysis results, countermeasures encompassing improvement of GF/PP pellets, adjustment of process parame￾ters, and tiny modification of the mold structure, etc. was pro￾posed, and was proved to be effective by the pedal arm manufacturer afterwards. Acknowledgement The work was supported by Shanghai Leading Academic Disci￾pline Project (Project Number: B113). References [1] Brady P, Brady M. Automotive composites: which way are we going? Reinf Plast 2007;51(10):32–5. [2] Hufenbach W, Langkamp A, Adam F, Krahl M, et al. An integral design and manufacturing concept for crash resistant textile and long-fibre reinforced polypropylene structural components. Procedia Eng 2011;10:2086–91. [3] Hufenbach W, Böhm R, Thieme M, Winkler A, et al. Polypropylene/glass fibre 3D-textile reinforced composites for automotive applications. Mater Des 2011;32:1468–76. [4] Yang ZG, Gong Y, Yuan JZ. Failure analysis of leakage on titanium tubes within heat exchangers in a nuclear power plant. Part I: Electrochemical corrosion. Mater Corros 2012;63(1):7–17. [5] Gong Y, Yang ZG, Yuan JZ. Failure analysis of leakage on titanium tubes within heat exchangers in a nuclear power plant. Part II: Mechanical degradation. Mater Corros 2012;63(1):18–28. [6] Gong Y, Yang C, Yao C, Yang ZG. Acidic/caustic alternating corrosion on carbon steel pipes in heat exchanger of ethylene plant. Mater Corros 2011;62(10):967–78. [7] Gong Y, Yang ZG. Corrosion evaluation of one dry desulfurization equipment – circulating fluidized bed boiler. Mater Des 2011;32(1):671–81. [8] Gong Y, Zhong J, Yang ZG. Failure analysis of bursting on the inner pipe of a jacketed pipe in a tubular heat exchanger. Mater Des 2010;31(9):4258–68. [9] Gong Y, Cao J, Meng XH, Yang ZG. Pitting corrosion on 316L pipes in terephthalic acid (TA) dryer. Mater Corros 2009;60(11):899–908. [10] Rjeb A, Tajounte L, Chafik El Idrissi M, et al. IR spectroscopy study of polypropylene natural aging. J Appl Polym Sci 2000;77:1742–8. [11] Abu-Isa I. Thermal degradation of thin films of isotactic polypropylene and polypropylene with ketonic additives. J Polym Sci Pol Chem 1970;8:961–72. [12] Heinen W. Infrared determination of the crystallinity of polypropylene. J Polym Sci Pol Chem 1959;38(134):545–7. [13] Luongo JP. Infrared study of polypropylene. J Appl Polym Sci 1960;3(9):302–9. [14] Beyler CL, Hirschler MM. Thermal decomposition of polymers. In: SFPE handbook of fire protection engineering. Quincy (MA, USA): National Fire Protection Association, Inc.; 2002. p. 125. [15] Ishiwatari M. Effect of temperature on the decomposition mechanism of polypropylene. J Polym Sci Pol lett 1984;22(2):83–8. [16] Lu QS, Sun LH, Yang ZG, Li XH, et al. Optimization on the thermal and tensile influencing factors of polyurethane-based polyester fabric composites. Compos Part A: Appl Sci Manuf 2010;41:997–1005. [17] Sun LH, Yang ZG, Li XH. Effects of the treatment of attapulgite and filler contents on tensile properties of PTFE and attapulgite reinforced fabric composites. Compos Part A: Appl Sci Manuf 2009;40:1785–91. Fig. 13. SEM micrographs of other areas away from the stress concentration corner (a, b) pulled-out glass fibers perpendicular to the fracture surfaces, and (c, d) long and curly organic fibers. Y. Gong, Z.-G. Yang / Composites: Part B 53 (2013) 103–111 111