Circular Economy (CE) and the potential of reusing and recycling the products after the end of their life, becomes imperative for environmental, economic and social reasons. Especially during the 4th Industrial Revolution that is taking place nowadays, an increasing number of out-of-date equipment has to be replaced, which constitutes a chance and necessity to be reused, through recycling, redesigning and remanufacturing. The paper presents proof-of-concept studies regarding upcycling of obsolete and outdated equipment into novel test rigs mainly addressing research activities. Three such case studies are presented, namely the upcycling of an injection moulding machine into a modular test bench for power hydraulic components, the upcycling of scrap components into a hybrid hydraulic/ ICE powertrain rig and the functional augmentation of a gear roll tester to accommodate single and double flank tests. Significant savings in cost, raw materials and time are demonstrated in all cases and adherence to the CE objectives are observed.

In recent years, the need for highly efficient automatic and semiautomatic powertrains has led to the wide use of wet friction clutches as power transmission systems. While wet friction clutches surpass their counterparts dry-friction clutches in the engagement process as they provide higher efficient torque and smoother torque and speed transmission, yet they fall behind in their disengaged state where the clutch acts as a power loss to the system due to the drag torque developed on the disks from fluid’s viscous shear stresses. Shear stresses are developed due to the relative speed difference of coaxial disks distanced at a prescribed axial clearance and rotating independently, yielding to a torsional Couette shear flow. This matter has been investigated thoroughly in the literature with experimental and numerical approaches for the case of flat disks admitting the complex flow pattern, which is augmented even more from the presence of geometrical features (grooves) on the surface of the disks. It becomes clear that the efficient calculation and understanding of drag torque can lead to its minimization and therefore to further establishing the use of wet clutches. In this work the effect of various disks geometrical features on the drag torque of a wet clutch is examined. The results are obtained via FEA (Finite Element Analysis) using the commercial software ANSYS.