This paper presents a new approach to numerical implementation of a classical Preisach model to hystersis modeling of Shape Memory Alloys (SMA). Classical Preisach hysteresis model is a phenomenological model and it offers various advantages over other models. After reviewing the basic properties of the classical Preisach model, this paper reveals one difficulty to numerically implement a classical Preisach model. Numerical simulations have to be done in two different cases: 1) when input ascends and 2) when input descends. Based on the geometrical interpretation, this paper proposed a unified approach to numerical implementation of a Preisach model and there is no need to consider the different cases. To demonstrate the effectiveness of the proposed numerical method, an experiment setup with an SMA wire with severe hysteresis is utilized. Experimental results convincingly demonstrate that the proposed method accurately captures the features of the hysteresis. Using the forward Preisach model, an approach to find the inverse model is presented for compensation purpose.
Simulation of piezoelectrically actuated valveless microupump (PVAM) indicates that both the pumping rate and membrane deflection amplitude will increase with the increase of the actuating frequency at a low frequency range (<7.5 kHz). However, because of the electro-mechanical-fluid coupling, the membrane deflects in an undesirable way at high frequencies. This will lower the pumping rate at high frequencies (>7.5 kHz). At even higher frequencies (>50 kHz), the
pumping rate will decrease further because the deflection amplitude decreases. This agrees with reported experimental results. The changing membrane deflection shape at various frequencies clearly plays an important role in the performance of the pump.