Osama M M, Selmy A I, Abdelhaleem Ayman M M, Megahed A A
Mechanical Engineering Department, Higher Technological Institute, Tenth of Ramadan city, Al-Sharqia, Egypt.
Mechanical Design and Production Engineering Department, Faculty of Engineering, Zagazig University, P.O. Box: 44519, Zagazig, Al-Sharqia, Egypt.
Sci Rep. 2022 Aug 30;12(1):14756. doi: 10.1038/s41598-022-18943-w.
This study is an investigation of weight fraction (wt%) and fiber feedstock length (FFSL) effects on the bearing strength (BS) of bolted joints in glass-fiber-reinforced (GFR) polypropylene (PP) composites manufactured by an injection molding technique. The investigation was made for holes produced either by molding or machining. For machined holes, the effect of drilling parameters (feed and speed) on BS was discussed. It is observed that BS decreased as FFSL increased. BS of both molded-in and drilled specimens was enhanced by increasing wt% of glass fiber. While slightly better BS was observed for molded-in specimens than drilled ones for all specimens. The drilling conditions' effect on BS was found to be insignificant for drilled holes in long fibers reinforced PP, where the most significant factor was wt%. However, for short fibers reinforced PP, the spindle speed was the most significant factor followed by feed, while wt% has the lowest effect. Failure morphology mode for specimens indicates that for molded-in specimens, neat PP specimens failed under pure bearing mode while GFR/PP specimens failed under the mixed-mode failure (bearing and net tension). For machined specimens, all specimens failed under mixed-mode failure except for the highest wt% specimens which failed under net tension.
本研究调查了重量分数（wt%）和纤维原料长度（FFSL）对采用注塑工艺制造的玻璃纤维增强（GFR）聚丙烯（PP）复合材料螺栓连接的承载强度（BS）的影响。对通过模塑或机械加工制成的孔进行了研究。对于机械加工的孔，讨论了钻孔参数（进给量和速度）对承载强度的影响。观察到承载强度随纤维原料长度的增加而降低。通过增加玻璃纤维的重量分数，模制和钻孔试样的承载强度均得到提高。对于所有试样，模制试样的承载强度略高于钻孔试样。对于长纤维增强聚丙烯中的钻孔，发现钻孔条件对承载强度的影响不显著，其中最重要的因素是重量分数。然而，对于短纤维增强聚丙烯，主轴速度是最重要的因素，其次是进给量，而重量分数的影响最小。试样的失效形态模式表明，对于模制试样，纯聚丙烯试样在纯承载模式下失效，而玻璃纤维增强聚丙烯试样在混合模式失效（承载和净拉伸）下失效。对于机械加工试样，除了重量分数最高的试样在净拉伸下失效外，所有试样均在混合模式失效下失效。
