Life cycle engineering of lightweight structures

Lightweight structures are increasingly necessary to meet current engineering requirements. Weight reduction in diverse applications such as automobiles or machine tools is achieved either by using less material or by substituting material with a lighter one, which provides more functionality per unit of weight. To be an effective enabler for sustainability, lightweight structures should result in lower environmental impacts per functional unit when compared to conventional structures on a life cycle basis. However, applying new materials and manufacturing processes often leads to an increase in environmental impacts from the raw materials and production stage of the life cycle. Furthermore, end-of-life disassembly and recycling may become more difficult. In addition, the expected efficiency gains from the use of lightweight structures depend on how the overall market and technical systems respond to them. Consequently, the environmental evaluation of lightweight structures in engineering entails various methodological challenges. Organised around a life cycle engineering framework with a focus on eco-effectiveness, this paper provides a comprehensive review of lightweight structure applications and the challenges and opportunities they present in a life cycle engineering context. (C) 2018 Published by Elsevier Ltd on behalf of CIRP.