The reported results refer to measurements obtained during the second thermal
cycle. Nominal stress profiles as functions of temperature for the three datasets
These deformation values are well below the
intersection region
The responses of the RC averaged on loading and unloading cycles are shown in Figure 6 for
different temperatures.
For deformations up to 40 %, the higher the temperature, the higher the
mean force exerted by the RC in correspondence of a given strain.
The loading curves at the
different temperatures mutually intersect in a tight region around 45 % strain and 60 MPa nominal
stress. For larger strains, the behaviour of the force with respect to the temperature is the opposite,
i.e. for very large values of the stress (and, thus, of the strain), the NC tends to extend when
temperature is increased. Notice also that the slopes of the curves are different. This means that it
is possible to control the stiffness of the actuator by varying the temperature. For example, for a
deformation ΔL/L0 = 0.07 a stiffness of 101 MPa or 78 MPa can be obtained with a temperature of
25 ◦C or 122 ◦C, respectively. This feature can be useful in a number of applications, e.g. vibration
control.