An Advanced Surrogate Model for Predicting the Impact of a SMA Twist System on the Helicopter Performance

Abstract

The paper at hand focuses on an advanced surrogate predictive model, conceived to estimate the impact on blade twist law of a Shape Memory Alloy actuation system. The basic idea is to integrate the pre-existing blade structure with a pre-twisted SMA tube. Due to the specific property of recovering deformation during phase transition, the SMA element can transmit angular deformations and alter the original twist to improve performance when required. The model at hand includes two main modules. The first one targets the SMA actuator and simulates the transmission of twist against some critical parameters (tube extension and location along the blade span and level of activation). The second module receives as input the modified twist law and the updated mechanical features due to the SMA and gives in output an estimate of the performance produced by the system. After an overview on input and output parameters and their cross link, a description of the SMA predicting core is provided. A parameterization is then organized to illustrate the impact of the morphing system onto the blade and on the twist law. On this basis, an additional parameterization is implemented, now focusing on the effects on performance of the proposed system.