考虑径厚比影响的圆柱壳滞回破坏机制分析

Analysis of Hysteretic Failure Mechanism of Cylindrical Shell Considering the Influence of Diameter-to-thickness Ratio

为了明确径厚比对于圆柱壳结构滞回性能的影响,通过低周往复荷载试验和数值模拟,研究了不同径厚比圆柱壳的滞回破坏模式和耗能能力。结果表明,径厚比会影响圆柱壳的最终破坏模式,随着径厚比的增大,破坏模式从底部象足式屈曲转变为褶皱式屈曲破坏。累积等效塑性应变和等效黏滞阻尼系数都随着径厚比的增大逐渐降低,径厚比越大,塑性发展越不充分,结构的耗能能力越弱。圆柱壳的塑性强化阶段随着径厚比的增大逐渐缩短,当径厚比超过250后,结构未经历塑性强化直接进入屈曲发展阶段,径厚比越大,局部屈曲出现越早,导致截面未达到全塑性弯矩即破坏,对于大径厚比圆柱壳结构的全塑性弯矩理论值应进行相应的修正。

In order to clarify the influence of diameter-to-thickness ratio on the hysteretic behavior of cylindrical shells, the hysteretic failure modes and energy dissipation capacity of cylindrical shells with different diameter-to-thickness ratios were studied through low cyclic load test and numerical simulation. The results show that the diameter-to-thickness ratio affects the buckling mode of the structure. With the increase of diameter-to-thickness ratio, the failure mode changes from bottom elephant foot buckling to fold buckling. Both the cumulative equivalent plastic strain and equivalent viscous damping coefficient gradually decrease with the increase of diameter-to-thickness ratio. The greater the diameter-to-thickness ratio, the less sufficient the plastic development and the weaker the energy dissipation capacity of the structure. The plastic strengthening stage of the cylindrical shell gradually shortens with the increase of the diameter-to-thickness ratio. When the diameter-to-thickness ratio exceeds 250, the structure directly enters the buckling development stage without plastic strengthening. The larger the diameter thickness ratio, the earlier the local buckling occurs, resulting in the failure of the section before reaching the full plastic bending moment. Therefore, the theoretical value of full plastic bending moment of cylindrical shell structure with large diameter thickness ratio should be modified accordingly.