Abstract The lack of research focused on quantifying the effects of fabrication process on the mechanical properties of carbon fiber sheet molding compounds (CF-SMCs) limited the industrial applications because the fabrication processes have a significant effect on the mechanical properties. Chopped carbon fiber tape reinforced thermoplastics (CTTs) are a novel type of CF-SMCs with outstanding mechanical performance. In this study, CTTs were molded using two fabrication processes, viz. Sheet molding (SM-CTT) and bulk molding (BM-CTT), and three tape thicknesses. The tensile tests of the specimens were conducted with in situ acoustic emission (AE) monitoring. Fractographs were also obtained for all specimens. The results indicated that fabrication processes have a prominent effect on the tensile properties of CTTs. The SM-CTTs demonstrated stable and superior mechanical performances than BM-CTTs for all tape thicknesses. The tensile properties deteriorated significantly with increase in tape thickness. The tensile moduli vary from 33.2 GPa to 42.9 GPa and tensile strengths vary from 186.2 MPa to 501.0 MPa with different fabrication processes and tape thicknesses. From the AE monitoring, the initial damages observed in BM-CTTs occurred in much earlier strain level comparing with the initial damages of SM-CTTs. Fiber breakage is the main failure mode in SM-CTTs with thin tapes, while interphase and interface debonding also observed in BM-CTTs and CTT with thick tapes. This paper addresses the lack of research on quantified effects of fabrication processes on the mechanical properties of CF-SMCs.

中文翻译：

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制造工艺和胶带厚度对短切碳纤维胶带增强热塑性塑料拉伸性能的影响

摘要 由于制造工艺对碳纤维片状模塑料 (CF-SMCs) 的机械性能的影响缺乏量化研究，这限制了其工业应用，因为制造工艺对机械性能有显着影响。短切碳纤维带增强热塑性塑料 (CTT) 是一种新型的 CF-SMC，具有出色的机械性能。在这项研究中，CTT 使用两种制造工艺进行模制，即。片材成型 (SM-CTT) 和批量成型 (BM-CTT)，以及三种胶带厚度。试样的拉伸试验是在原位声发射 (AE) 监测下进行的。还获得了所有样品的断口图。结果表明，制造工艺对 CTT 的拉伸性能有显着影响。对于所有胶带厚度，SM-CTT 均表现出比 BM-CTT 稳定且优越的机械性能。拉伸性能随着胶带厚度的增加而显着恶化。拉伸模量从 33.2 GPa 到 42.9 GPa 不等，拉伸强度从 186.2 MPa 到 501.0 MPa 不等，具有不同的制造工艺和胶带厚度。从 AE 监测来看，与 SM-CTT 的初始损伤相比，BM-CTT 中观察到的初始损伤发生在更早的应变水平。纤维断裂是带薄带的 SM-CTT 的主要失效模式，而在 BM-CTT 和带厚带的 CTT 中也观察到相间和界面脱粘。本文解决了缺乏对制造工艺对 CF-SMC 机械性能的量化影响的研究。