A shape memory alloy (SMA) composition of Ni 60 Ti 40 (wt%) was chosen for the fabrication of active beam components used as cyclic actuators and incorporated into morphing aerospace structures. The active structure is a variable-geometry chevron (VGC) designed to reduce jet engine noise in the take-off flight regime while maintaining efficiency in the cruise regime. This two-part work addresses the training, characterization and derived material properties of the new nickel-rich NiTi composition, the assessment of the actuation properties of the active beam actuator and the accurate analysis of the VGC and its subcomponents using a model calibrated from the material characterization.The second part of this two-part work focuses on the numerical modeling of the jet engine chevron application, where the end goal is the accurate prediction of the VGC actuation response. A three-dimensional (3D) thermomechanical constitutive model is used for the analysis and is calibrated using the axial testing results from part I. To best capture the material response, features of several SMA constitutive models proposed in the literature are combined to form a new model that accounts for two material behaviors not previously addressed simultaneously. These are the variation in the generated maximum actuation strain with applied stress level and a smooth strain-temperature constitutive response at the beginning and end of transformation. The accuracy of the modeling effort is assessed by comparing the analysis deflection predictions for a given loading path imposed on the VGC or its subcomponents to independently obtained experimental results consisting of photogrammetric data. For the case of full actuation of the assembled VGC, the average error in predicted centerline deflection is less than 6%.

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As active structures become more prominent, the use of more capable numerical modeling has gained importance as an aid to the design process. The need to accurately account for the response of Shape Memory Alloys (SMAs) under complex loading paths has become increasingly important. Such paths are general in a stress-temperature space and may induce irreversible deformation (plasticity). In addition, the structural utilization of active SMA components often includes large deformations, specifically large rotations. This is especially important in beam bending and torsional applications. This work proposes a new method for implementing a phenomenological SMA model originally formulated using small strains into a numerical framework which preserves objectivity given large rigid body rotations. The implementation is shown to be straightforward, and example analyses are performed which demonstrate the usefulness of this capability. An extension of the model to include the generation of plastic strains is also discussed. Alterations to the numerical algorithms are addressed which allow the analysis of simultaneous transformation and yielding. Additional analyses are performed on structural members undergoing transformation and yielding while at the same time moving through large rotations.