振动筛空间动力学建模及弹簧受损分析

Spatial Dynamics Modeling and Spring Damage Analysis of Vibrating Screen

在三维空间中基于Lagrange法建立振动筛四自由度动力学模型,能够描述振动筛在空间中上下、左右平动,前后、左右摆动的振动特性。使用MATLAB软件采用Newmark-β法对动力学模型进行数值仿真,通过改变不同位置的弹簧刚度值来模拟弹簧损伤,分析弹簧受损导致的弹簧刚度变化对振动筛各个自由度方向振幅变化的影响。实例数值计算表明,y、z两个方向的振幅受弹簧损伤的影响极其微小,y方向振幅变化系数绝对值不超过0.08%,z方向振幅变化系数绝对值不超过0.8%;弹簧受损导致出、入料两端弹簧总刚度差值的变化对振动筛θ方向的振幅影响极大,两端总刚度差值减小时,θ方向振幅减小,不利于筛面物料向前运动,容易发生物料堆积现象,差值增大时,θ方向振幅增大,利于物料向前运动,提高筛分效率;振动筛弹簧刚度受损使得y轴两侧弹簧刚度分布不均,振动筛易发生φ方向的摆动,导致筛面物料发生跑偏现象,y轴两侧弹簧刚度差值越大,物料跑偏越严重。

Based on Lagrange method,a four-DOF dynamic model of vibrating screen was established,which can describe the vibrating characteristics of vibrating screen moving up and down,left and right,and swinging back and forth and left and right.The Newmark-β method was used to simulate the dynamic model by using MATLAB software.The spring damage was simulated by changing the spring stiffness values at different positions,and the influence of the spring stiffness changes caused by the spring damage on the amplitude changes of each freedom direction of the vibrating screen was analyzed.The numerical calculation of the example showed that the amplitudes of y and z directions were very little affected by the spring damage.The absolute value of the amplitude variation coefficient in y direction was less than 0.08%,and the absolute value of the amplitude variation coefficient in z direction was less than 0.8%.The spring damage caused the change of the total stiffness difference of the spring at both ends to greatly affect the amplitude of the vibrating screen in the direction.When the total stiffness difference at both ends decreases,the amplitude in the direction decreases,which was not conducive to the forward movement of the material on the screen surface,and the accumulation of the material was easy to occur.When the difference increased,the amplitude in the direction increased,which was conducive to the forward movement of the material and the screening efficiency was improved.Vibration screen spring stiffness damage caused uneven distribution of spring stiffness on both sides of the y axis,vibration screen was easy to swing in the g direction,resulting in screen surface material deviation phenomenon,the greater the difference in spring stiffness on both sides of the y axis,the more serious material deviation.