On the Development of a Passive Shape Memory Alloy- Based Cooling System – Part II: Design Justification

The use of shape memory alloy (SMA)-based actuators is more and more increasing, thanks to the potential benefits in terms of actuation power/weight ratio and weight reduction, if compared to traditional electromechanical actuators. In this paper, part of the Research and Development activities finalised to the prototyping of a SMA-based cooling system device for automotive applications is introduced. The SMA actuator is passively controlled by the temperature reached in the engine compartment. Indeed, the increase of temperature beyond a predetermined threshold, triggers, by means of the SMA-based actuator, a set of cooling flaps which dissipate the heat accumulated in the engine compartment. Actually, the performed extensive development activity has been split into two parts which are presented in two papers. The present paper focuses on part II, dealing with detailed finite element analyses and optimization, aimed to the numerical justification of the design; while, part I, focused on Design, Manufacturing and Testing of the proposed passive cooling system, is presented in a parallel paper. The evolution of the geometrical configurations of the SMA-based cooling system device, throughout the design and optimization phases, is shown. Finally, results from detailed finite element analyses, performed on the final executive design configuration and aimed to verify the fulfilment of SMA device operating requirements, are introduced and commented to justify the choices made in the frame of the design phases.