This work describes modeling of non-linear damping behavior in hybrid beam structures with SMA embedded layers. The dependency of the intrinsic damping capacity of SMAs on the strain is simulated through modeling of material’s hysteresis cycle. The hysteresis cycles and the corresponding loss-factors have been investigated through uniaxial tensile test and have been reproduced and validated by numerical simulation. To do so, a phenomenological hysteresis model has been developed and implemented in ABAQUS through UMAT interface. Finally, the method was used to simulate the damping of hybrid beam structures with SMA embedded layers and the results were compared with experimental data.
Wind turbine blades are being bigger and bigger, thus requiring lightweight structures that are more flexible and thus more sensitive to dynamic excitations and to vibration problems. This paper investigates a preliminary architecture of large wind turbine blades, embedding thin sheets of SMA to passively improve their total damping. A phenomenological material model is used for simulation of strain-dependent damping in SMA materials and an user defined material model was developed for this purpose. The response of different architectures of SMA embedded blades have been investigated in the time domain to find an optimal solution in which the less amount of SMA is used while the damping of the system is maximized
The performance of lightweight structures can be severely affected by vibration. New design concepts leading to lightweight, slender structural components can increase the vulnerability of the components to failure due to excessive vibration. The intelligent approach to address the problem would be the use of materials which are more capable in dissipating the energy due to their high value of loss factor. Among the different materials available to achieve damping, much attention has been attached to the use of shape memory alloys (SMAs) because of their unique microstructure, leading to good damping capacity. <p> </p>This work describes the design and optimization of a hybrid layered composite structure for the passive suppression of flexural vibrations in slender and light structures. Embedding the SMA layers in composite structure allows to combine different properties: the lightness of the base composite (e.g. fiber glass), the mechanical strength of the insert of metallic material and the relevant damping properties of SMA, in the martensitic phase. In particular, we put our attention on embedding the CuZnAl in the form of thin sheet in a layered composite made by glass fiber reinforced epoxy. By appropriately positioning of the SMA sheets so that they are subjected to the maximum curvature, the damping of the hybrid system can be considerably enhanced.<p> </p> Accordingly analytical method for evaluating the energy dissipation of the thin sheets with different shapes and patterns is developed and is followed by a shape optimization based on genetic algorithm. Eventually different configurations of the hybrid beam structure with different patterns of SMA layer are proposed and compared in the term of damping capacity.