A New Thermoelastic Model for Analysis of Shape Memory Alloy Hybrid Composites

Abstract

A constitutive model and a finite element formulation are developed for predicting the thermomechanical response of SMA hybrid composite structures subjected to combined thermal and mechanical loads. The constitutive model is valid for constrained, restrained, or free recovery behavior with appropriate measurements of basic SMA material properties. The model captures the material nonlinearity of the SMA with temperature and more accurately captures the mechanics of composites with embedded SMA actuators as compared to other recently developed approaches. The constitutive and finite element models are amenable to commercial code implementation. The fundamental thermoelastic behavior of such structures is described in physical terms and related to the governing equations. It is shown that alloy selection is imperative for achieving the desired performance with respect to the application environment. It is also shown that fundamental efforts to strategically place actuators can produce dramatic performance improvements. Numerical results are shown for glass-epoxy beam specimens with embedded Nitinol actuators. Control of critical buckling temperature, thermal post-buckling deflection, and random response are demonstrated.

Smart structure dynamics

“…A particularly practical 1-D SMA model has been developed in [16]. This model expresses the constitutive relation for an 1-D SMA actuator in terms of an effective coefficient of thermal expansion,…”

<title>Experimental validation of a thermoelastic model for SMA hybrid composites</title>

“…In the present example, the second buckling temperature would be in excess of the epoxy matrix glass-transition temperature (193.3°C, 380°F). These phenomena are described in more detail elsewhere [5][6][7] . There it is also shown that thermal buckling can be avoided altogether for such configurations by proper alloy selection, but the example shown here serves as an excellent test-bed for behavior demonstration and model validation.…”

“…A thermomechanical model was recently developed to study the static and dynamic response of such SMAHC structures [5][6][7] . The goals of this study are to present experimental results from static and dynamic tests of SMAHC beam specimens for validation of the theoretical model and for control performance demonstration.…”

Development of a SMA hybrid composite jet engine chevron concept

“…That work also provided the first shape control experimental validation for a recently commercialized (MSC.Nastran and ABAQUS) constitutive model for SMAHC materials and structures [24][25][26][27] . The objectives of the present work are to design a SMAHC chevron with the cylindrical nozzle curvature, develop fabrication approaches for curved SMAHC chevron concepts, and perform bench-top testing of chevron prototypes for performance demonstration and correlation with numerical predictions.…”