振動荷重を受ける梁の進行性変形発生条件に関する研究
概要
According to experimental observations, the failure modes of piping in nuclear power plants caused by large seismic motion are fatigue or ratchet deformation. However, the mechanism of ratchet deformation under the large seismic load is not so clear. In this study, authors conducted experiments and analysis of beams which simulates piping due to cyclic sinusoidal or more complicated waves (composite sinusoidal wave). As the results, authors confirmed that ratchet deformation occurrence conditions are strongly affected by the frequency of input wave. Moreover, he mechanism of ratchet deformation was explained from the view point of energy transfer from input loading to the beam and amplification factor of the beam.
