单层网壳结构冲击响应模式及临界冲击动能研究

STUDY ON IMPACT RESPONSE MODES AND CRITICAL IMPACT KINETIC ENERGY OF SINGLE-LAYER RETICULATED SHELL

采用ANSYS/LS-DYNA对60m跨度的K-6型单层球面网壳建立有限元模型,通过大量参数分析得出K-6网壳的4种冲击响应模式及其变化规律,考虑材料屈服强度、弹性模量及杆件截面积对网壳冲击响应模式及其分布规律的影响,提取网壳在冲击作用下发生局部倒塌和整体倒塌时的临界冲击动能,比较材料特性及截面特性对网壳抗冲击性能的影响,拟合了临界冲击动能的计算公式,并与有限元结果进行了对比。结果表明,K6网壳的冲击响应模式随冲击物携带动能的改变呈规律性变化。在杆件的截面特性和材料特性中,杆件的截面积对网壳的抗冲击性能影响较大,提高杆件的截面积可以大幅度提高网壳抵抗冲击荷载的能力。网壳的临界冲击动能可以利用公式进行计算。该结果对于网壳结构的抗冲击设计具有实际意义。

A finite element model for Kiewitt-6 type single-layer reticulated shell with 60m span was established by ANSYS/LS-DYNA. 4 kinds of impact response modes and change laws were obtained by parameter analysis. The material yield strength, modulus of elasticity and cross-sectional area of a member were considered as the influencing factors to impact response mode and distribution law. The critical impact kinetic energy was extracted to compare the influence of materials and the cross section on impact resistance.The formulas of critical impact kinetic energy were fitted and compared with finite FEM. The results show that the impact response model for K6 reticulated shell changes regularly with kinetic energy carried by impact loading, and the impact resistance can be improved significantly by extended the cross section area of a member. The critical impact kinetic energy of reticulated shell can be calculated by a formula. These results have practical significance for the impact resistance design of a reticulated shell.