A life cycle analysis of novel lightweight composite processes: Reducing the environmental footprint of automotive structures

Stephanie Wegmann,Christian Rytka,Mariona Diaz-Rodenas,Vincent Werlen,Christoph Schneeberger,Paolo Ermanni,Baris Caglar,Colin Gomez,Véronique Michaud

doi:10.1016/j.jclepro.2021.129808

Abstract

In this study, three novel thermoplastic impregnation processes were analyzed towards automotive applications. The first process is thermoplastic compression resin transfer molding in which a glass fiber mat is impregnated in through thickness by a thermoplastic polymer. The second process is a melt-thermoplastic Resin Transfer Molding (RTM) process in which the glass fibers are impregnated in plane with the help of a spacer. The third process, stamp forming of hybrid bicomponent fibers, coats the fibers individually during the glass fiber production. The coated fibers are used to produce a fabric, which is then further processed by stamp forming. These three processes were compared in a life cycle analysis (LCA) against conventional resin compression resin transfer molding with either glass or carbon fibers and metal processes with either steel or aluminum that can be new, partly or fully recycled using the case study of the production, life and disposal of a car bonnet.The presented LCA includes the main phases of the process: extraction and preparation of the raw materials, production and preparation of the mold, process, and energy losses. To include the life of the analyzed bonnet, the amount of diesel that is used to drive the weight of the bonnet for 300′000 km is calculated. In this LCA, the disposal of the bonnet is integrated by analyzing the used energy for the recycling and the incineration. The results show the potential of the developed thermoplastic impregnation processes producing automobile parts, as the used energy producing a thermoplastic bonnet is in the same range as the steel production.

Highlights

Tackling the climate change is one of the major challenges of the 21st century, which requires a reduction of the emission of greenhouse gases such as carbon dioxide or methane (Schryver et al, 2009)
This study aims to compare these three processes with the estab lished thermoset compression resin transfer molding (C-Resin Transfer Molding (RTM)) process and metal processes for the case study of the production, use and disposal of a car bonnet driven with diesel
When replacing glass with carbon fibers for the C-RTM pro cess, we find that the reduced fuel consumption does not compensate for the higher energy required to produce carbon fibers

Summary

Introduction

Tackling the climate change is one of the major challenges of the 21st century, which requires a reduction of the emission of greenhouse gases such as carbon dioxide or methane (Schryver et al, 2009). The longing to reduce carbon dioxide (CO2) emissions of cars is in direct conflict with the continuous expansion of the automotive sector and in the case of passenger cars, with the increasing comfort and safety standards leading to an increase of weight and ecological impact. This is supported by a study investigating the impact on climate change of Volkswagen Gold models over their entire life cycle over the last thirty years (Danilecki et al, 2017). To comply with the reduction of CO2 emissions imposed in several countries, a more ecological design of the vehicles is necessary

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