Experimental Evaluation of the Impact Mechanics in the Rocking Dynamics of Rigid Blocks

The rocking dynamics of multi-block masonry structures plays a crucial role in seismic safety assessments, particularly in the preservation of built heritage. Although Housners model [1] is the classical reference for describing rocking motion, it assumes perfectly rigid blocks and predicts the dynamic behaviour only on the basis of the geometric parameters. This aspect is closely related to the Coefficient of Restitution (CoR), which should depend not only on the geometry of the impacting bodies, but also on their mechanical properties and initial impact velocity. Thus, theoretical modeling of the rocking phenomenon raises significant challenges, especially in estimating energy losses during impacts. Despite the considerable theoretical developments achieved over time to accurately determine this parameter, it is clear that experimental results are essential to accurately understand the complex nature of rocking motions. Here, the Authors present the results of an extensive experimental campaign of rocking tests conducted on reduced-scale specimens. Moreover, the rocking blocks have been tested on contact with support base of different materials in order to investigate the influence of mechanical properties on the dynamic response. Experimental evidence supported the development of a new theoretical approach to the study of contact mechanics in the rocking dynamic. The proposed approach takes into account the local deformation at the interface of the two bodies considering the mechanical properties of materials differently from the traditional theoretical model developed by Housner.