许林云, 卢峻达, 张涛. 基于等效静态载荷法的大型振动筛轻量化处理[J]. 农业工程学报, 2022, 38(9): 24-33. DOI: 10.11975/j.issn.1002-6819.2022.09.003
    引用本文: 许林云, 卢峻达, 张涛. 基于等效静态载荷法的大型振动筛轻量化处理[J]. 农业工程学报, 2022, 38(9): 24-33. DOI: 10.11975/j.issn.1002-6819.2022.09.003
    Xu Linyun, Lu Junda, Zhang Tao. Lightweight treatment of large vibrating screen using equivalent static loads[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2022, 38(9): 24-33. DOI: 10.11975/j.issn.1002-6819.2022.09.003
    Citation: Xu Linyun, Lu Junda, Zhang Tao. Lightweight treatment of large vibrating screen using equivalent static loads[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2022, 38(9): 24-33. DOI: 10.11975/j.issn.1002-6819.2022.09.003

    基于等效静态载荷法的大型振动筛轻量化处理

    Lightweight treatment of large vibrating screen using equivalent static loads

    • 摘要: 振动筛广泛应用于农业、煤矿、木工等行业,且均朝着大型化、高效化方向发展。大型振动筛工作一段时间后较易出现裂纹等疲劳破坏现象。该研究针对新型BF14260大型振动筛,分析了整体结构强度,确定了最大等效应力位置及主要应力分布区域,结合等效静态载荷法和子模型法,构建振动筛筛箱主框架等效静态子模型,将动态优化问题转化为静态优化问题,进行拓扑概念优化及实用模型重建,进一步进行局部强化处理,分析比较了不同处理方法的最大及较大应力节点的动态等效应力变化关系。结果显示拓扑优化处理全面有效降低应力值,且有效降低动态应力波动频率,即改善梁受力波动的稳定性以提高梁的疲劳工作寿命;局部强化处理在拓扑优化处理基础上明显降低了最大等效应力值,即使整个梁构件承载的应力获得全面有效的下降,改善了应力分布。最终优化效果为最大应力由79.4 MPa下降至49.3 MPa,下降37.9%。质量减轻1 080 kg,减少了25.6%。该研究所提方法可有效解决复杂结构的动态优化问题并提高优化效率。

       

      Abstract: A vibrating screen has been widely used in agriculture, coal mining, and woodworking industry. High efficiency of vibrating screens has been required for large-scale production in recent years. However, the structure can inevitably bear the large dynamic load, leading to fatigue damage, such as some cracks after working for a period of time. The reason is that the large dynamic inertia force can be generated by the body mass of a large vibrating screen. In this study, the overall structural strength of the newly developed BF14260 large vibrating screen was analyzed to determine the position of the maximum equivalent stress and the main stress distribution area using the combined test and finite element simulation. The main frame model of the vibrating screen box was constructed to combine the equivalent static load and sub-model method. The structural displacement fields under the equivalent static load and dynamic load at a certain time were transformed from the dynamic response optimization into structural static optimization. Moreover, the calculation scale was reduced to greatly improve the optimization and calculation efficiency. Then, the equivalent static sub model was topologically optimized with the variable density, in order to identify the material distribution for the best structural performance. As such, the optimal conceptual model was obtained to reconstruct the practical model. The three-dimensional and dynamic partial stress relationship of the maximum or greater stress nodes in each structure after topology optimization was compared to further improve the structural strength of the vibrating screen. The vibrating screen structure was then strengthened to add some stiffeners. The research results show that the most beams bore small stress, and the mass of the main frame of the vibrating screen accounted for about two-thirds of the mass of the components of the vibrating box, except that the vertical beam connected with the outrigger and the beam on the H1 plane were the main load-bearing beams, in terms of the dynamic stress cloud diagram of the original structure for one week, and the dynamic stress cloud diagram of the time point of the maximum equivalent stress. The structure after topology optimization effectively reduced the stress and the fluctuation frequency of dynamic stress, while the mass was reduced by 28.5% than before, indicating the stability of stress fluctuation for the better fatigue life of the beam. The local strengthening treatment significantly reduced the maximum equivalent stress of each supporting main beam in the vibrating screen, even if the stress carried by the whole beam member was reduced, indicating the uniform stress distribution after topology optimization. The final optimization was that the maximum stress decreased from 79.4 to 49.3 MPa, indicating a decrease of 37.9 % than before. The weight was reduced by 1 080 kg and 25.6%. Consequently, the combination of equivalent static load and sub model method can be widely expected to transform the dynamic into static optimization. Among them, the main research objects were separated by the cutting boundary position interpolation method. Correspondingly, dynamic optimization can effectively deal with complex structures for the high optimization efficiency in the structure design of vibrating screens during large-scale production.

       

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