Ricerc@Sapienza

The model of a non-smooth oscillator with hysteresis and impacts will be proposed in order to perform an overall optimization of an innovative Shock Absorber (SA) by means of numerical and experimental investigations. The starting point for the research is an existing multi-purpose device proposed and patented in recent years by Lacarbonara and Carboni, which is characterized by hysteretic restoring forces provided by assemblies of shape memory alloys and steel wire ropes. The hysteretic behavior exhibited by the device is due to the concurrency of inter-wire friction, phase transformations of the shape memory alloy and geometrically induced nonlinearities. In order to develop a Shock Absorber with optimized performances, several configurations will be considered and compared taking into account the influence of soft and hard impacts on the device dynamic response. The improved Shock Absorber will be finally tested to control the nonlinear vibrations of a 2DOF system composed by a main structure to be protected and by the Shock Absorber itself.

The expected results will lead to an advance of the knowledge on different topics: these cover both basic problems related to the modeling of non-smooth systems and more technological issues related to the design and experimental validation of improved devices for shock absorption and vibration mitigation. Furthermore, on the level of the understanding of the dissipative features of this type of device, the project will produce innovative phenomenological models for shape memory alloys. The project will finally provide a refinement of innovative and traditional techniques for the analysis of highly nonlinear and non-smooth systems and for an optimized dynamical response identification.