【摘要】 应用ANSYS/LS-DYNA建立60m跨度凯威特型球面网壳(扇形三向网格单层球面网壳)与圆柱形冲击物的数值模型并展开分析。依据网壳的动力响应,提出顶点竖向冲击荷载下网壳结构的四种失效模式,但动力响应及失效模式与冲击初始条件间缺乏规律性。对冲击的特点及网壳动力特性的分析则发现:以顶点响应速度(一次冲击结束时刻网壳顶点的速度)为自变量时,网壳最终动力响应呈现很好的规律性,并且可以依据顶点响应速度对网壳的失效模式进行判别。最后鉴于网壳受冲击荷载的数值模型建立困难且计算繁琐,提出获取顶点响应速度的理论计算方法,且理论结果可以替代数值结果进行失效模式的判别。达到了由冲击初始条件经简化的理论计算判别网壳失效模式的目标。其中理论方法的核心是网壳冲击区范围的确定与冲击区折算质量的推导。更多还原

【Abstract】 FE models of both the Kiewitt reticulated dome(single-layer reticulated dome with three-dimensional grids sector) with of the span of 60m and a cylindrical impactor were developed,incorporating ANSYS/LS-DYNA.Four failure modes were proposed according to the dynamic response of impact on the apex of the Kiewitt reticulated dome based on numerical analysis.It was found that the correlations between the initial impact conditions and the failure modes were insignificant.However,there was close correlation between the response velocity of the impacted joint,i.e.the velocity of the impacted joint just after the first impact,and the dynamic responses of the dome was revealed.The response velocity was used to judge the failure modes.Theoretical solution of the response velocity was achieved by means of the defined impact zone and the equivalent mass of the zone.The response velocity and the judgment of the failure modes of the dome can be obtained by using the simplified theoretical approach,without sophisticated FE modelling.更多还原