随机地震激励下门机动态响应及可靠度分析

Analysis on Dynamic Response and Reliability of Gantry Crane Under Random Earthquake Excitations

基于随机振动理论,对门机进行随机地震激励下的动态响应分析。采用一致多维平稳随机地震响应分析方法,数值仿真了门机在七种不同方向地震激励组合下门机的地震响应。根据结构随机动力反应的统计矩,运用随机过程的极值理论对门机进行了基于首超破坏准则的动力可靠性分析。结果表明:考虑多维地震输入可能会使结构应力增加58.8%;在X+Z向地震输入下门机的可靠度最低;有Z向地震波分量参与的地震输入容易导致门机倾覆、主梁断裂。

Based on the theory of random vibration, the dynamic response on gantry crane under random seismic excitation was investigated. The random seismic analysis and single point spectrum analysis of structural＇s force and displacement were researched under six different earthquake model inputs with uniform multi-dimensional earthquake excitations method, then compared the results with response spectrum method. According to the statistical moments of random dynamic response af the structure, used extreme value theory of stochastic processes, analyzed the dynamic reliability of gantry crane base on the first excursion failure criterion. The analysis reveal that structure stress may be increased signifwantly when considering the three- dimensional earthquake excitation; the results of random seismic response analysis are safer than spectrum analysis under the same earthquake excitation, the dynamic reliability reaches the minimum under X ＋Z direction excitation, and seismic input involving Z direction excitation is easy to lead crane＇s overturning and girder fracture.