Snap-through of a Shallow Arch under Random Loading.

摘要

Dynamic stability of shallow structures, such as arches, curved panels, and buckled beams and plates, has been studied extensively. Instability is characterized by 'snap-through', in which all or part of the structure deflects into an inverted configuration. Most previous investigations have assumed that the loading is deterministic (e.g., step, pulse, impulse, or harmonic loads). This paper investigates the instability of a shallow arch subjected to random loading. The parameter of interest is the time of first snap-through (i.e., inversion). In most of this study, the loading is a stationary white-noise process with zero mean. Galerkin's method is used to discretize the equation of motion, usually with one or two modes, and Monte Carlo simulation is applied to obtain probability density functions and reliability functions, based on the gamma distribution. The paper examines the effects of the spatial distribution of the load, the load intensity, the mean load, the damping magnitude, the arch height, and the inclusion of multiple response modes. A critical load intensity for snap-through is determined. Examples of nonstationary loads modeling earthquakes are presented, and results are compared to those for the white-noise case. Keywords: Stochastic excitation, Reprints. (edc)