【作者】 霍鹏飞；

【导师】 杨洁明；

【作者基本信息】 太原理工大学 ， 机械电子工程， 2010， 硕士

【摘要】 直线振动筛具有结构简单、振动强度大、筛分效率高、处理能力大等优点,广泛应用于矿山、煤炭、冶炼、建材、化工等领域,用于物料的筛选、脱水、分级等工艺。但由于振动筛在较高振动频率下工作,筛体承受较大的交变激振力,在实际工作中经常出现下横梁断裂,侧板开裂等疲劳破坏,严重影响生产。尤其随着振动筛向大型化方向发展,疲劳破坏更加严重,所以迫切需要在设计阶段进行疲劳寿命分析,提高产品的可靠性。传统的疲劳寿命预测主要针对具体的物理样机进行试验,耗费大量的人力、物力、财力。而且,如果物理样机试验不合格,还要重新设计,反复试验,直至合格。这样造成大量浪费,开发和测试成本大大提高。随着计算机技术的发展,特别是动力学仿真技术和有限元技术的发展,使得其应用于产品疲劳寿命分析成为可能,克服了传统试验法的不足。本文借鉴国内外大量的虚拟疲劳耐久性集成化仿真方法,以某大型直线振动筛为研究对象,对其下横梁和侧板进行了疲劳寿命分析。首先利用Pro/E对某大型振动筛零部件进行三维实体建模、组装和干涉检查;然后,利用动力学仿真软件MSC.ADAMS建立了振动筛的多刚体动力学模型,对其进行仿真分析,获得位移、速度、力等信息,为下横梁、侧板的刚柔耦合动力学分析提供了刚体模型;利用有限元前后处理器MSC.PATRAN,求解器MSC.NASTRAN分别对下横梁和侧板进行自由模态分析,获得固有频率和固有振型,为疲劳寿命分析提供了模态信息和柔性体;而后,在MSC.ADAMS中,分别建立了以下横梁、侧板为柔性体,其它零部件为刚性体的刚柔耦合动力学模型,为疲劳寿命分析的载荷谱提供了模态位移;最后,在疲劳分析软件MSC.FATIGUE中,根据材料的S-N曲线,利用模态应力恢复法分别对下横梁和侧板进行疲劳寿命分析,获得其疲劳寿命云图和结构危险部位。通过对该振动筛疲劳寿命分析结果与实际破坏情况相比较,二者相互吻合,说明这种虚拟疲劳耐久性集成化分析系统应用于振动筛的疲劳寿命分析是可行的,它能够减少物理样机的数量,缩短产品的开发周期,进而降低开发成本,提高市场竞争力。同时,本文的研究对振动筛的可靠性设计具有一定的参考和借鉴价值。更多还原

【Abstract】 Linear vibrating sieve is widely used in mining, coal, metallurgy, building materials, chemical industry etc., for materials selection, dehydration, grading etc., due to its simple structure, strong vibration intensity, high screening efficiency and processing capacity etc.. However, the body has to bear a larger alternating excitation force at higher vibrating frequency, so it often appears fatigue damage such as cracking of the lateral plate and beams in practical work, which is seriously affecting production. Especially with the development of vibrating sieve towards large-scale direction, fatigue damage is becoming more severe. It is urgent to improve the fatigue life of the reliability of products in the design stage.Traditional prediction of fatigue life focuses on specific physical prototype tests, which is a waste of manpower, materials and financial resources. Moreover, if the physical prototype test fails, it is need to re-design the product and check errors until success, result in substantial increase in development and test costs. With the development of computer technology, especially the dynamics simulation and finite element technology, it becomes possible to be applied in product fatigue life analysis, overcoming the shortcomings of the traditional test methods.Based on some linear vibrating sieve, this paper analyses fatigue life of the beams and lateral plate according to a large number of virtual fatigue durability integrated simulation methods at home and abroad. Firstly, 3-D models of sieve parts are established,assembled and checked interference by Pro/E. Secondly, the multi-rigid-body dynamics model of vibrating sieve is established through MSC.ADAMS, and the simulation analysis is carried on, obtaining displacement, velocity and force, etc., which provides a rigid model for the rigid-flexible coupling dynamic analysis of the beam and lateral plate. Thirdly, free modal analysis is carried on through finite element processor MSC.PATRAN and solver MSC.NASTRAN respectively, acquiring the natural frequencies and natural mode of vibration, which provides the modal information and flexible body for fatigue life analysis. Then, the rigid-flexible coupling dynamic model is established with the beam and lateral plate being the flexible body, the other parts the rigid body in MSC.ADAMS, which provides modal displacement for the load spectrum for fatigue life analysis. Finally, the beam and lateral plate are analyzed by using modal stress recovery method in fatigue analysis software MSC.FATIGUE, according to the material S-N curve, in order to obtain the fatigue life of Moire figure and structure of dangerous position. The result of the fatigue life analysis is in accordance with actual damage, indicating it is feasible for the virtual fatigue durability integrated analysis system to be applied in vibrating sieve fatigue life analysis, which can reduce the number of physical prototypes, shorten the development cycle of products, reduce development costs and improve market competitiveness. At the same time, this paper has a certain reference value for further studies on the reliability of the vibrating sieve.更多还原