Current Work: Shape Memory Alloys

In order to utilize a shape memory alloy, the properties of the alloy need to be known.  Charlotte Lelieveld from the TU Deflt has done work in creating smart composites materials, i.e. materials that incorporate shape memory alloys and shape memory polymers (1-2).  Pictures of her work is given below:



Smart Composite using Shape Memory Polymers and Shape Memory Alloys


Prototype of smart composite when the structure is activated

In order for me to create a similar, I need to know the properties of both the shape memory alloy and shape memory polymer. The properties of relevant importance to me are listed below:

Shape Memory Alloys (3):
1. Density (g/cc): 6.5
2. Electrical Resistivity (micro Ohms/cm): 76 (Martensite)/82 (Austenite)
3. Thermal Conductivity (W/m deg C): 18
4. Elastic Modulus (GPa): 40 (Martensite)/75 (Austenite)
5. Specific Heat Capacity (J/kgK): 322

The power to heat the SMA strips, can be found through estimating the energy by (1):

E = Power*time = mass*Specific Heat Capacity* change in temperature

The power may be calculated from Joule’s law:

P = Voltage^2/Resistance

The resistance in each wire is given by:
R = resistivity * length/cross-sectional area

1. Lelieveld, C. M. J. L. (2013). Smart Materials For The Realization Of An Adaptive Building Component. Ph.D. doctoral Thesis, Delft University of Technology.


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