STOCHASTIC RESPONSE QUANTIFICATION OF FIXED-BASE AND BASE-ISOLATED RIGID-PLASTIC BLOCKS

. The paper deals with the modelling, response quantification and vibration control of rigid-plastic blocks in presence of stochastic forcing with indicative application to seismic engineering. The full dynamic interaction between a sliding block and a linear base-isolation system is considered and efficient piecewise numerical solutions are derived for analysing its true nonlinear response, in comparison with its base-fixed counterpart. Two forms of stochastic forcing are then considered, namely, white noise excitation, and a modified version of the Kanai-Tajimi power spectrum suggested by Clough and Penzien, commonly used in earthquake engineering applications. A statistical linearisation approach is adopted in view of approximat-ing the strongly nonlinear systems during the sliding motion regime, which conveniently permits quantification of the steady-state, stationary response statistics. The effectiveness of the base isolation in suppressing the extreme forcing delivered to the block is assessed. The work delivers insights into the determination and understanding of the probabilistic characteristics of the response of dynamically driven base-fixed and base-isolated rigid-plastic systems, further encouraging investigations on other types of structures, isolation systems and hazard scenarios.