Fuzzy-based sustainability modeling: Case study of remanufacturing waste sheet steel into angle mesh steel

Remanufacturing of waste sheet steel (WSS) recovered from the shells of exterior components of end-of-life vehicles is a sustainable alternative to recycling and landfilling. It is proposed that producing angle mesh steel (AMS) from this WSS is a novel sustainable business model. In this case study, 1 to 1.25-m long strips of WSS were disassembled from the roof, bonnet, boot, rear and front doors, and fenders, and were formed into mesh with three different expansion ratios (2.19, 5.94, and 12.19). The expanded strips were flattened and roll formed into AMS sections for construction purposes. An integrated multi-criteria sustainability assessment of the technical, economic, environmental, and social factors was conducted to identify the 20 most-sustainable alternatives of end-of-life passenger cars from 200 designs manufactured between 2009 and 2019. The most sustainable exterior components for WSS to AMS remanufacturing were those that achieved a high closeness coefficient compared to the optimal performance. A pre-assessment was conducted to specify the complexity of remanufacturing by integrating the presence of topological discontinuities (inhomogeneous areas of the sheets that impede effective roll forming) within fuzzy modeling analysis. Both the important criteria and performance of the exterior-component alternatives were fuzzified to construct a performance-of-remanufacturing matrix and calculate the closeness coefficient of each alternative. The acquired experience from practical remanufacturing was applied to enable fuzzification-aided analysis. A final performance score was obtained by summing all relevant coefficients to analyze the sustainability of the 200 target car designs for remanufacturing WSS into AMS. The best component for remanufacturing is the roof, followed by the hood, boot, front door, and front fender in this order. The Volkswagen Passat with few discontinuities in the WSS was the best alternative, while Ford Fusion designs were the worst. The findings show that the remanufacturing route is viable and provide guidance for selecting the most appropriate components and vehicle models for efficient remanufacturing.