钢混结构分离式有限元建模方法由于考虑了钢筋的实际分布, 其计算精度较高, 但建模过程复杂繁琐。开展了基于动刚度等效的钢混结构简化建模研究, 该方法将钢筋和混凝土考虑为一种等效材料。研究中首先以典型钢混组合结构为例, 以等效模型与分离式模型的模态特性等效为目标, 建立了分部件的动刚度等效模型, 然后将各部件等效模型组合成整体结构等效模型, 数值仿真结果显示在相同载荷作用下, 整体参考模型与整体等效模型的响应分布非常接近, 而等效模型的规模远小于参考模型, 说明了该等效建模方式的有效性。进一步将该等效建模方法应用于神光Ⅲ主机靶室钢混结构的动力学分析中, 并计算了该巨型光机结构等效模型在实测基础加速度激励下的随机振动响应, 靶球上各方向的响应实测结果与计算结果较为吻合。所采用的动刚度等效建模方法可应用在巨型光机结构动力学稳定性的进一步研究中。

The discrete model of reinforced concrete structure considers the actual distribution of rebars, and with high accuracy, but the modeling process is complex. A kind of simplified modeling method is adopted to establish the finite element reinforced concrete model of opto-mechanical structure of ICF. This method is a kind of integrated modeling method with the equivalent modal feature of discrete model, by which concrete and rebar are considered as a kind of equivalent material. For typical combined structure, equivalent component models are obtained, and these equivalent models are assembled as a general structure. The numerical simulation results indicate that, under the same excitation, the response of discrete model and equivalent model is rather close, and the size of equivalent model is rather smaller than that of discrete model, and the effectiveness of equivalent modeling method is validated. At last, this equivalent modeling method is applied in opto-mechanical structure of the ICF facility SG Ⅲ, the random response of target ball is calculated under tested base excitation, and the simulation result and test data match well. The equivalent modeling method could be used in further stability analysis of giant opto-mechanical structures.