中文摘要：

针对大型振动筛结构可靠性差，使用寿命低的问题，利用有限元法对新型超静定网梁结构香蕉筛进行动态特性分析，对其结构进行动力学优化，并建立了准确的有限元计算模型以提高分析精度。对轴承、激振器结构进行了简化，引入了虚梁，并改进了激振力的加载方式。分析了香蕉筛的固有频率和固有振型，根据分析结果对香蕉筛出料端结构进行了优化，提高了筛体弯曲、扭转变形的固有频率，从而有效地避免共振，降低结构的破坏程度。对优化后的筛体进行动应力分析，结果表明：该香蕉筛在工作频率下，筛箱横向变形降低，动应力减小，整个筛体结构刚度和强度增加，提高了香蕉筛的稳定性和可靠性．

英文摘要：

In order to improve service life and structural reliability of large vibrating screen, the paper analyses the dynamic characteristics of new type banana vibrating screen with hyperstatic net-beam by finite element method and conducts dynamic optimization for the strueture of the vibrating screen. It also establishes precise analysis model of the vibrating screen so as to improve the analysis precision. Moreover, the paper structurally simplifies the bearing and vibration exciter, applies the virtual beam and improves＇ the loaded method of exciting force on the model. It analyses the screen＇s natural frequency and natural vibration mode as well as optimizes the discharge end structure of banana screen according to the analysis results. Modal analysis results show that natural frequency of bending and torsional deformation of the vibrating screen increases, thus resonance can be effectively avoided and structural destruction reduced. Dynamic response results of the optimized vibrating screen shows that the lateral deformation of the screen weakens＇ and the dynamic stress decreases under operational frequency. In addition, the structural stiffness and strength of the screen increases and the stability and reliability of screen improves.