This thesis presents a new metric-based Life-cycle Assessment (LCA) method for assessing the sustainability performance of metallic automotive components. The unique feature of this research work include the development and use of a metrics-based product sustainability index (ProdSI) methodology by considering the total life-cycle approach and the triple bottom line (TBL) with the 6R methodology. It has been shown that the manufactured product’s sustainability performance can be comprehensively assessed using this new methodology. The major focus of this research is the integration of the 6R activities (Reduce, Reuse, Recycle, Recover, Redesign and Remanufacture). Four life-cycle stages of the product, with various end-of-life (EOL) product scenarios, are modeled and analyzed. These scenarios include: reuse, remanufacturing, and recycling the products at EOL. Furthermore, a new mathematical model is developed and presented to determine the optimum percentage mix for various product EOL strategic options. By using the 6R methodology, the overall product sustainability was significantly improved. This improvement was quantitatively assessed by computing the ProdSI score. Ultimately, this research shows that a closed-loop material flow can be achieved.

Ny teknik utvecklas idag i snabb takt. Produkter blir allt mer avancerade och fler funktioner ska finnas med i respektive produkt utan att tjänsterna blir för avancerade för slutanvändarna att förstå eller använda. Det här är någonting som designers utbildas till att förstå allra bäst; hur produkter optimalt ska utformas och struktureras för respektive målgrupp. Dock involverar utvecklare och designers sällan de tilltänkta slutanvändarna i designprocessen för att ta fram en optimalt anpassad produkt för den specifika målgruppens behov. I denna studie undersöks hur en digital stödapplikation kan utvecklas tillsammans med äldre vuxna användare och hur en deltagande designmetod kan stärka användarnas egenmakt både i relation till applikationen och inom ramen för en designprocess. Studien undersöker även vilka styrkor och svagheter deltagande designmetoder kan ha för äldre vuxna som deltar i dessa processer. / New technology is developing at a rapid pace. Products are becoming increasingly advanced and more features should be included in each product without the services being too advanced for end users to understand or use. This is something that designers are trained to know best; how products are designed and structured to be optimally presented to each targeted audience. However, developers rarely involve the intended end users in the design process to produce an optimally customized product. The work examines how a digital support application can be developed together with older adult users, using participatory design to enable empowerment, both within the study itself, and in the application. The study also examines what strengths and weaknesses the design method has for older adults.