Irreversible Thermodynamics and Smart Materials Systems Modelling. Example of Magnetic Shape Memory actuators

Smart systems is a very promising technology to design high performance and highly integrated mechatronic devices. Nevertheless, one of the main drawbacks of these devices is the complex non-linear and irreversible behaviour of the active materials at the heart of such systems. To solve these difficulties, this paper presents a thermodynamics based procedure to model more accurately active materials. After a review on energy conversion modelling techniques, the paper extends classical thermodynamics procedure to the case of irreversible processes. The use of internal state variables helps to improve the physical understanding of non-linear and irreversible mechanisms in smart materials. This procedure is applied to Magnetic Shape Memory Alloys actuators and the results are quite encouraging. Modelling methods proposed in this paper improves the understanding of complex active materials for smart systems.