![[ Visit Client Website ]](images/banner.gif)
Monday, September 22, 2008: 3:15 PM
Auditorium (Palazzo dei Congressi di Stresa)
Shape memory alloy (SMA) represents the most versatile way to realize smart materials with sensing, controlling and actuating functions. Due to their unique mechanical and thermodynamic properties, and to the possibility to obtain SMA wires with very small diameters they are used as smart components embedded into the conventional resins or composites to obtain active abilities, tunable properties, self healing properties, damping capacity. Moreover superelastic SMAs are used to increase the impact resistance properties of composite materials.
In this study the influence of the integration of thin superelastic wires to suppress propagating damage of composite structures has been investigated. In fact superelastic SMA have very high strain to failure and recoverable elastic strain, due to a stress induced martensitic phase transition creating a plateau region in the stress-strain curve. NiTi superelastic wires (Af = -15°C fully annealed) of 0.10 mm in diameter have been produced and characterized by SAES Getters. The straight annealed wire shows the typical flag stress-strain behavior. The measured loading plateau is around 450 MPa at ambient temperature with a recoverable elastic strain of more than 6%.
For these reasons superelastic SMA fibers can absorb much more strain energy than other fibers before their failure, partly with a constant stress level. So with this current investigation it has been studied how embedding SMA wires into composite laminates can enhance the impact properties, and some indications for the design and realization of SMA composites with high impact properties have been found.
In this study the influence of the integration of thin superelastic wires to suppress propagating damage of composite structures has been investigated. In fact superelastic SMA have very high strain to failure and recoverable elastic strain, due to a stress induced martensitic phase transition creating a plateau region in the stress-strain curve. NiTi superelastic wires (Af = -15°C fully annealed) of 0.10 mm in diameter have been produced and characterized by SAES Getters. The straight annealed wire shows the typical flag stress-strain behavior. The measured loading plateau is around 450 MPa at ambient temperature with a recoverable elastic strain of more than 6%.
For these reasons superelastic SMA fibers can absorb much more strain energy than other fibers before their failure, partly with a constant stress level. So with this current investigation it has been studied how embedding SMA wires into composite laminates can enhance the impact properties, and some indications for the design and realization of SMA composites with high impact properties have been found.