Citation

Bondy M, Altenhof W. Int. J. Crashworthiness 2020; 25(4): 401-420.

Copyright

(Copyright © 2020, Informa - Taylor and Francis Group)

DOI

10.1080/13588265.2019.1602973

PMID

unavailable

Abstract

Few studies/bodies of data are available in the open literature on the topic of mechanical material characterisation and structural performance for direct/inline compounded long fibre thermoplastic (LFT) automotive parts, particularly incorporating carbon fibre. Therefore, this study aimed to comprehensively document the mechanical properties of a seatback for a lightweight automotive seating design, compression moulded from carbon fibre/polyamide 66 on a Dieffenbacher LFT-D manufacturing line. The methodology consisted of extracting and characterising mechanical behaviour of tensile specimens from full seatback components and completing quasi-static and low velocity impact loading on these seatbacks. Both longitudinal and transverse charge placements within the compression mould were considered. Main findings from the tensile tests noted a dependency of the mechanical properties based upon the location from which specimens were extracted; from the charge region, the elastic moduli in the 0° and 90° directions were similar (0°: 14.0 GPa & 90° 15.9 GPa with coefficients of variation (CoV) of 56% and 36%, respectively) or, for the case of specimens extracted from the flow region, exhibited significant anisotropy (elastic moduli in the 0° direction 9.79 GPa and 90° direction 21.6 GPa, with CoV's of 16% and 23%). In terms of anisotropy of the full seatback component, under low velocity impact loading a local force maxima was observed for seatbacks produced with a longitudinal charge orientation at deflections of approximately 15 to 20 mm. No local maxima were consistently observed for transverse charge seatbacks. In terms of rate effects, stiffness was 550% higher for low velocity impact with respect to quasi-static loading. Digital image correlation identified a greater level of deformation, particularly away from the indenter, for quasi-static loading. Catastrophic failure occurred at larger deflections for low velocity impact (36% increase for longitudinal charge placement, 24% for transverse). The results of this investigation have practical applications for engineers in industry considering direct/inline compounded carbon fibre LFT materials in cases where quasi-static and dynamic loading will be present, for example, automotive chassis/body structural components.

Language: en

Keywords

carbon fibre; Composites; digital image correlation; impact; long fibre thermoplastic; polyamide 66