This paper is a study on the numerical modeling and the accordance between model and experiment of the behavior of Shape Memory Alloys (SMA) used as functional devices for application in Instrumentations for Astronomy. Some NiTi alloy samples was characterized using different experimental techniques, with the purpose of obtaining the material parameters, necessary to evaluate the correspondence between the simulation and the experimental behavior of the materials. The sensibility of the computational model to the variation of this parameters for the materials was investigated as well. Opto-mechanical mounting with pseudoelastic kinematic behavior and damping of launch loads onto optical elements are feasible applications that are investigated in this paper. The practical realization of a scaled down prototype is described. The device was thought for ground-based applications and made up of four small flexures that support an optical component and was designed and modeled in order to be able to evaluate the mechanical effects of different materials. The results of numerical modeling was compared to the data obtained from the prototype. We obtained a first evaluation of the development, selection and processing of NiTi-based supports for optomechanical applications and verified the performances of a complete system as a respect to an analogous system made up using traditional materials like steels.
This paper wants to illustrate possible applications of Shape Memory Alloy (SMA) as functional devices for space
and ground based application in Instrumentations for Astronomy. Thermal activated Shape Memory Alloys are
materials able to recover their original shape, after an external deformation, if heated above a characteristic
temperature. If the recovery of the shape is completely or partially prevented by the presence of constraints, the
material can generate recovery stress. Thanks to this feature, these materials can be positively exploited in Smart
Structures if properly embedded into host materials. Some technological processes developed for an ecient use
of SMA-based actuators embedded in smart structures tailored to astronomical instrumentation will be presented
here. Some possible modeling approaches of the actuators behavior will be addressed taking into account trade-
offs between detailed analysis and overall performance prediction as a function of the computational time. The
Material characterization procedure adopted for the constitutive laws implementation will be described as well.
Deformable composite mirrors,1 opto-mechanical mounting with superelastic kinematic behavior and damping
of launch loads onto optical element2 are feasible applications that will be deeply investigated in this paper.