考虑重力效应的单层球面网壳抗冲击荷载性能

为研究冲击荷载作用下网壳结构的动力响应,应用有限元软件ANSYS/LS-DYNA建立60m跨度K8型单层球面网壳的冲击模型并进行数值分析,计算对比是否考虑重力效应两种情况下,网壳在冲击荷载作用下的动力响应.得出产生差异的主要原因:网壳结构的自重敏感性、离心力效应与几何大变形.由此得出结论:只有考虑重力效应,即冲击荷载与重力荷载同步施加到结构时,所得的动力响应才是准确的.在上述基础上,对135个K8型网壳算例进行分析,研究表明:网壳竖向变形和主要杆件受力随着冲击质量与速度的增加而增大,当质量与速度增加到一定值后,二者均不再变化.

PERFORMANCE FOR SINGLE-LAYER RETICULATED DOMES UNDER IMPACT LOAD AND GRAVITY

To investigate the dynamic response of reticulated domes under impact load,a model of KIEWITT8 single-layer reticulated dome with span of 60 m was established and simulated by ANSYS/LS-DYNA. The dynamic response of dome under impact load was calculated and compared with or without the consideration of gravity. Results show that gravity sensitivity,effect of centrifugal load,large displacement of geometry all cause the difference between the two situations. Moreover,the exact dynamic response can not be obtained without the consideration of gravity. Moreover,the analysis on 135 examples indicates that the vertical displacement and stress of main elements increase with the increasing impact mass or impact velocity,but they do not change after increasing the impact mass or impact velocity to a certain degree.