MODEL AND SIMULATION STUDIES ON VARIATIONS OF NATURAL FREQUENCIES FOR WOODEN STRUCTURE WITH AND WITHOUT DAMAGES

摘要

The purpose of this study is to compare the variations of natural frequencies and try to make the tendency clear while the structures without, with slight and with heavy damages. Two real wooden structures in the campus of Kinki University have been used, with different construction methods. The comparisons between the simulation results using ANSYS soft and the vibration results from the two different model structures on the shaking table have been shown. , with real earthquake input and sine wave input. The damages have been obtained by cutting off the columns and beams step by step. It is clear that the simulations results identify with the shaking table results and have clearly shown that, for one construction type, the natural frequency decreased following the increase of damage, but for the other type, the natural frequency remains unchanged even the damage increases. It is strange that even if the degree of damages increases, the natural fre- quency remains unchanged. Such results will have minus effect for the research itself of structural health monitoring.