单层鞍形网壳强动力荷载作用下的破坏模式

Dynamic failure mode of single-layer saddle-shaped reticular shell

采用ANSYS程序,利用全过程分析方法对两种不同网格形式的单层鞍形网壳结构在强简谐、地震荷载下的动力响应规律进行研究,提取最大节点位移、应变能、进塑性杆件比例等多项响应指标,绘制其随荷载幅值增大的变化曲线,总结单层鞍形网壳的动力失效模式,剖析其失效机理,分析了地震作用下结构响应随矢跨比的变化规律.研究结果表明,两类网格的单层鞍形网壳均具有良好的抗震性能,在强动力荷载作用下发生动力强度破坏,可区分为脆性破坏和延性破坏两种失效模式.地震作用下结构破坏模式均为延性强度破坏.

Non-linear dynamic analyses for single-layer saddle-shaped reticular shells with two types of grid form subjected to both harmonic and earthquake waves are performed in FEM software ANSYS.Based on numerical analysis results of a great number of typical cases,multi-indexes responses from macroscopic and microscopic levels,which can be used for exploring the failure mechanism,are obtained.Typical failure modes of such structures are investigated.Furthermore,the dynamic failure modes and the effect of rise-span ratio for single-layer saddle-shaped reticular shells are presented.The results show that the single-layer saddle-shaped reticular shells have good anti-seismic behavior.The collapse of such structure is caused by dynamic strength failure,which can be specified to brittle failure and ductile failure by apparent response characteristics.And the dynamic failures of two types of shells subjected to earthquakes are both ductile.