浅い円筒形曲面パネルの外圧による座屈と非線形ランダム振動応答の解析 ＩＩ 非線形ランダム振動応答

Abstract

Probabilistic properties of nonlinear response of cylindrical panels to random excitation are studied by simulation method to disclose the effects of curvature of the panel on the sonic fatigue life. Simultaneous nonlinear differential equations derived in the part I are solved numerically by NEWMARK's β method and the fatigue life is calculated with a cumulative damage rule. The results show that the curvature is effective to prevent sonic fatigue when the exciting force is not large and the response is small, but harmful when the response is very large. The following response properties are revealed. The PDF of stress decreases much more slowly at the high positive stress region than that of gaussian process does when the response of the panel seldom exceeding the point of the snap-through buckling or the minimum rigidity. In the case where the panel response is very large, the dominant mode of vibration becomes one-half-wave pattern and different from the normal mode of vibration.