EXPERIMENTS AND SIMULATION OF OVERTURNING OF AN ASYMMETRIC ROCKING BLOCK ON AN OSCILLATING FOUNDATION

This paper describes what happens when the base upon which a relativel y slender rigid block rests is subjected to a horizontal harmonic acce leration. The force transmitted to the block may be sufficient to init iate rocking or even cause overturning. The number of times the block impacts the base before it overturns (if it does) may vary by a consid erable amount. Transient rocking and overturning depend very sensitive ly on the forcing parameters (amplitude and frequency) and exhibit cer tain fractal characteristics. Some of the subtle phenomena obtained by numerical simulation are demonstrated by experiments in this investig ation. Although the physical experiments described in this paper are r elatively simple in terms of geometry, parameter ranges, and modeling assumptions, the emphasis throughout is on qualitative behavior. Despi te these limitations, the inherent sensitivity of the dynamics poses s ome profound questions regarding the concept of experimental repeatabi lity.