Fundamental studies on solid-state stamp forming of unidirectional fibre reinforced thermoplastics for automobile components
File(s)
Author(s)
Wang, Hongyan
Type
Thesis
Abstract
Climate change has led to extensive research on lightweight materials for transportation industries, and unidirectional fibre reinforced thermoplastics (UD FRTPs) stand out due to their exceptional properties. To incorporate UD FRTPs into vehicles, a cost-effective manufacturing method suitable for mass production is necessary. In this regard, solid-state stamp forming offers potential due to its short cycle time and energy-saving capabilities. Despite its potential, challenges arise from insufficient lab experiments, limited understanding of deformation behaviours, and lack of material models.
This thesis aims to address the challenges of solid-state stamp forming for complex-shaped UD FRTPs by encompassing four major facets:
1) Experimental characterisation and mechanism analysis of thermoplastics, with a particular focus on polyamide 6 (PA6) and polyether ether ketone (PEEK). It confirms the feasibility of solid-state stamp forming and identifies initial processing windows for FRTP materials.
2) Experimental characterisation and mechanism analysis of UD FRTPs. Specifically, an automotive-grade material, unidirectional carbon fibre reinforced polyamide 6 (UD CF/PA6) was studied. The developed knowledge and understanding helps to refine the forming windows for UD FRTPs and provides crucial insights for the process design.
3) Constitutive model development and numerical simulation, by creating two sets of unified physically based constitutive models to describe the deformation of thermoplastics and UD FRTPs, respectively. These models are subsequently implemented into commercial Finite Element Analysis (FEA) software for process simulations of solid-state stamp forming of UD FRTPs, enabling the analysis of potential defects and optimal processing parameters.
4) Stamp forming experiments and post-form analysis via forming dome-shaped demonstrator components. The post-form quality is assessed using various methods, which validates the findings from earlier studies. The successful production of stamp-formed demonstrators indicates the promising potential of using UD FRTPs in the automotive industry.
This thesis aims to address the challenges of solid-state stamp forming for complex-shaped UD FRTPs by encompassing four major facets:
1) Experimental characterisation and mechanism analysis of thermoplastics, with a particular focus on polyamide 6 (PA6) and polyether ether ketone (PEEK). It confirms the feasibility of solid-state stamp forming and identifies initial processing windows for FRTP materials.
2) Experimental characterisation and mechanism analysis of UD FRTPs. Specifically, an automotive-grade material, unidirectional carbon fibre reinforced polyamide 6 (UD CF/PA6) was studied. The developed knowledge and understanding helps to refine the forming windows for UD FRTPs and provides crucial insights for the process design.
3) Constitutive model development and numerical simulation, by creating two sets of unified physically based constitutive models to describe the deformation of thermoplastics and UD FRTPs, respectively. These models are subsequently implemented into commercial Finite Element Analysis (FEA) software for process simulations of solid-state stamp forming of UD FRTPs, enabling the analysis of potential defects and optimal processing parameters.
4) Stamp forming experiments and post-form analysis via forming dome-shaped demonstrator components. The post-form quality is assessed using various methods, which validates the findings from earlier studies. The successful production of stamp-formed demonstrators indicates the promising potential of using UD FRTPs in the automotive industry.
Version
Open Access
Date Issued
2023-07-15
Date Awarded
2023-10-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Li, Nan
Childs, Peter
Lin, Jianguo
Sponsor
Imperial College London
China Scholarship Council
Publisher Department
Dyson School of Design Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)