Many structures, such as dry-stone structures, historical monuments, AGR graphite core in nuclear power plants and masonry structures after the failure of the binder, consist of multiple discrete bodies, which can go through complex motion when subject to earthquake, human-structure interaction etc. This complex motion can sometimes be simplified to rocking – rotation of rigid bodies around its bottom corners with changes between corners. Under given dynamic excitation rocking can result in overturning, which can eventually cause failure of the structure.
One of the most important mechanisms during rocking is the loss of mechanical energy every time a collision between any two bodies occurs (which happens any time a body switches from rotation around one corner to rotation around the other corner, or when rocking bodies standing next to each other collide). This energy loss usually works favourably to the dynamic response of the structure, but it needs to be further investigated and related to the geometry and size of the rocking body.
The described energy-loss mechanism will be investigated experimentally (by designing and conducting multiple experiments with collisions between rocking bodies, which will be measured via optical techniques) and numerically (by developing a numerical algorithm and simulating the experiments). This will provide a better understanding of the energy loss during rocking of rigid bodies and help in estimating the safety of multiple-body structures in earthquakes.

Project is financially supported by UKF.
Duration: August-November 2019.
UKF funding: 36 000 HRK.
Matching funding: 34 300 HRK.

Research team:
Nina Čeh, Faculty of Civil Engineering, University of Rijeka (Website)
Nikica Petrinić, Department of Engineering Science, University of Oxford (Website)

Institutions:
Faculty of Civil Engineering, University of Rijeka
Department of Engineering Science, University of Oxford