Damping of rod vibrations caused by impact

Vibration damping through phase transformation is one major area of application of shape memory alloys in smart systems and structures. The authors of this study have shown in earlier publications, how damping of vibrating rods can be accomplished. Phase transformation due to heating/cooling is the tool for vibration damping in the past and present work. Here, an elastic, polycrystalline rod is considered, which is initially at rest, and from the time t equals 0 on dynamically loaded. The loading function (pressure in the dependence on time) is in the simplest cases rectangular or bell-shaped. Special cases exist, which are equivalent to the release waves discussed in earlier papers. Heating/cooling is performed at the fixed end of the -- after the impact -- freely vibrating rod. This causes phase transformation on some parts of the rod according to the stress-temperature diagram. Thus, the governing equations are the heat conduction equation, the stress wave equation, the kinetic law to describe the phase transformation, and finally the constitutive law as well as a condition to ensure maximal damping. An integral equation algorithm is adapted to the impact problem for the numerical simulation. Results are provided for different impact types and heating/cooling histories. These show the decrease of the energy divided by the impact energy depending on time.