单层球面网壳的最不利简单动荷载分析

同时考虑了几何非线性与材料非线性,分别对简谐荷载、阶跃荷载作用下的单层球面网壳进行了最不利动荷载分析:通过变换简谐荷载的频率和阶跃荷载的持时,明确了结构动力响应与其自振特性及荷载频谱特性之间的关系,确定了何种条件下的荷载为结构最不利动荷载。结果表明:无论是水平还是竖向简谐荷载,当激励荷载频率与激励作用方向最大振型参与系数所对应的固有频率接近时,为结构的最不利动荷载;无论是水平还是竖向阶跃荷载,当荷载持时为荷载作用方向最大振型参与系数所对应的固有周期的1/2时,为结构的最不利动荷载。

Analysis of the Most Unfavorable Simple Dynamic Loads for Single-layer Spherical Latticed Shells

Through simultaneously considering geometric non-linear and material non-linear,the dynamic responses of single-layer spherical latticed shells subjected to harmonic loads and step loads were researched respectively,and the most unfavorable dynamic loads of the structure were analyzed.Under the analysis of dynamic behavior of single-layer spherical latticed shells subjected to harmonic loads with different frequency and step loads with different duration,the relationships between the structural dynamic response and its self vibration characteristic,as well as the load frequency characteristic were built up,by which the most unfavorable loads of single-layer spherical latticed shells were determined.The results show that under either horizontal harmonic loads or vertical harmonic loads,when the excitation load frequency is closed to the natural frequency which corresponds to the largest vibration mode participation coefficient in the direction of excitation,the limit harmonic load is the lowest;when the duration of step load is closed to the half of natural period which is versus the largest modes of vibration participation coefficient in the direction of excitation,the limit step load is the lowest.