According to the structure and mechanical characteristics of vibrating screen,the beam-shell element model was put forward, and the solution of key problem in finite element modeling was given. Using custom section beam ele- ment,the actual beam structure was simulated by variable cross section beam;the bolts connection and welded connec- tion were simplified rational by freedom degrees eoupled and constraint equations technology;the exciting force was ap- plied to structure rational by creating rigid zone. Integrating theoretical analysis and experimental modal analysis re- sults, it shows that ： compared with traditional solid element model, using beam-shell element model, the dynamic analy- sis results are more precise, it takes less computational resources, and the computing reliability is higher. Dynamic analysis of large vibrating screen can be computed in general PC by using beam-shell element model.%根据振动筛结构和受力特点，提出梁壳单元模型，给出有限元建模中关键问题的解决方法：采用自定义截面梁单元，实现了用变截面梁模拟振动筛实际梁结构；用自由度耦合及建立约束方程的方法实现结构中螺栓连接、焊接连接的合理简化；建立刚性区，合理施加激振力栽荷。结合理论分析和实验模态分析结果表明：采用梁壳单元模型进行大型振动筛动力学分析较传统实体单元模型具有精度高、计算资源占用少、计算可靠性高的优点。采用梁壳单元模型可以在一般PC机上实现对大型振动筛结构动态有限元分析。
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