# Spring Failure Analysis of Mining Vibrating Screens: Numerical and Experimental Studies
###### Abstract  
Spring failure is one of the critical causes of the structural damage and low screening efficiency of mining vibrating screens. Therefore, spring failure diagnosis is necessary to prompt maintenance for the safety and reliability of mining vibrating screens. In this paper, a spring failure diagnosis approach is developed. A finite element model of mining vibrating screens is established. Simulations are carried out and the spring failure influence rules of spring failure on the dynamic characteristics of mining vibrating screens are obtained. These influence rules indicate that the amplitude variation coefficients (AVCs) of the four spring seats in the \(x\), \(y\), and \(z\) directions can reveal two kinds of single spring failure and four kinds of double spring failure, which are useful for diagnosing spring failure. Furthermore, experiments are conducted. Comparison analyses of the experimental results and simulation results indicate that the proposed approach is capable of revealing various kinds of spring failure. Therefore, this approach provides useful information for diagnosing spring failure and guiding technical staff to routinely maintain mining vibrating screens. Keywords:mining vibrating screen; finite element model; spring stiffness decrease; failure diagnosis; amplitude variation coefficient +
Footnote †: journal: Applied  
Aimed at spring failure diagnosis, [PERSON] et al. presented a rigid plate structure to describe the isolation system and proposed the method of stiffness identification by stiffness matrix disassembly; their numerical simulation results demonstrated the feasibility of this method [25; 26]. Additionally, [PERSON] et al. developed a diagnostic methodology for identifying the stiffness of damping springs with a free response. The asymmetric dynamic model of the vibrating screen with a damping spring fault was established, and the vibration differential equation was derived. Then, the discrete free acceleration response data were processed and subsequently constructed in matrix form to obtain the modified stiffness matrix. Moreover, by disassembling the stiffness matrix and defining the stiffness assurance criterion, the principle and procedures for stiffness identification of a large vibrating screen were summarized. Finally, they carried out an experimental test to verify the validity of the developed method for stiffness identification [27]. [PERSON] et al. developed a two-dimensional, three-degree-of-freedom nonlinear model that considered angular motion and damping, which allowed for the prediction of the behavior of a vibrating screen when there was a reduction in spring stiffness, and they used this model to determine a limit on spring failures before the separation efficiency was affected [28]. [PERSON] et al. proposed a six-degree-of-freedom theoretical rigid body model of a mining vibrating screen and established the dynamic equation in order to explore the dynamic characteristics. Six kinds of spring failure were selected for simulations, and the results indicated that the spring failures led to an amplitude change of the four elastic support points in the \(x\), \(y\), and \(z\) directions, where the changes depended on certain spring failures. The conclusions provided a theoretical basis for further study and experimentation on spring failure diagnosis for mining vibrating screens [29]. The above studies investigated a few particular cases of mining vibrating screens with spring failures by using theoretical models in which the screen is modelled as a rigid body without structural distortions. However, the mining vibrating screen box is composed of multiple beams and large thin plates, and it produces partial elastic deformation during system vibration. Additionally, spring failures may impact the mining vibrating screen's dynamic characteristics. The finite element method is widely used for dynamics analysis and failure diagnosis [30; 31; 32; 33; 34; 35].