Lightweight disc springs based on a composite sandwich architecture

This work evaluates the quasi-static compressive response and single-cycle hysteretic behaviour of carbon-fibre/epoxy Belleville disc springs manufactured by vacuum bagging (VB) and compression moulding (CM), with and without thermoplastic polyurethane (TPU) infill. The experimental matrix permits a direct comparison of the manufacturing routes for the common [0/90/0/90]s lay-up and a separate comparison of [0/90/0/90]s and [90/0/−45/+45]s laminates within the CM route. Quasi-static compression and loading-unloading tests are used to examine how consolidation route, laminate architecture, stacking configuration, and TPU thickness affect stiffness, displacement, and hysteretic energy dissipation. CM produced thinner and lighter discs with a higher estimated fibre volume fraction than VB. For the common [0/90/0/90]s lay-up, CM provided a higher mass-specific compression limit despite a slightly lower conservative absolute compression limit. Series arrangements increased displacement and loading energy, whereas parallel configurations increased effective stiffness. Among the parameters investigated in the single-cycle tests, TPU thickness produced the largest systematic change in hysteretic response; the 5 mm inserts generated the highest loading-energy and dissipated-energy ratios. The results establish the mechanical feasibility of the proposed lightweight sandwich-like disc-spring architecture and provide a basis for further replicated cyclic and durability studies.