Debonding on demand of additively manufactured sandwich structures – a multi-domain index calculation for a robust circular design innovation

The implementation of circular economy concepts has become inevitable in the face of progressive resource depletion and increasing waste generation. However, in academia and industry, the focus is mainly on the conceptual, economic, or logistical implementation at a high level. At the product level, conducting a precise technological feasibility study and evaluating circularity strategies in different areas is crucial to facilitate the transition towards resource optimization and waste reduction. In this context, this study proposes a debonding-on-demand (DoD) of an innovatively designed polymer sandwich structure consisting of a lower-melting temperature additively manufactured polypropylene (PP) honeycomb core structure and a higher-melting temperature glass fiber prepreg embedded in a PP matrix. The innovatively developed design allows for disassembly, recycling and reassembly of the sandwich structure. Trough the additive manufacturing process, load path adaption, optimization, and adjustment of varying material properties is effortless realizable.In addition, the manufacturing process is supported by different service-life simulations. Based on primary data, a new, innovative, and comprehensive assessment of manufacturing, performance, cost, and sustainability is performed. With the collected manufacturing data, a disassembly index was developed to evaluate multi-component products. The results demonstrate the potential of customizable, additively manufactured sandwich structures based on thermoplastic materials. The newly developed debonding mechanism and the thermo-mechanical recycling enable the reuse of the core material with comparable properties. The proposed multi-domain-based disassembly index is a comprehensive tool to evaluate the feasibility of products or material combinations after their useful life and can support the transition to a more data-driven circular engineering approach.