Dynamic And Fatigue Analysis Of Coal Preparation Sieve Bend

The structure or components of coal preparation sieve bend are prone tofatigue failure under the action of chronic alternating excitation force, impactand friction of materials, resulting in decreased work efficiency and enterprisebenefit reduction. In order to avoid serious damage by fatigue failure, the fatiguelife of structure or important components need to analyze in the design stage.Compared to the traditional physical prototype test method, the fatigue lifeanalysis with virtual prototype technology has the advantages of saving humanresources, reducing cost and shortening the development cycle, etc, so it is moreand more applied to research, product design and development.The research object of this paper is VSB302060type coal preparationsieve bend, the fatigue life of sieve plate arc seat, which is the importantcomponent of coal preparation sieve bend, is analyzed with the stress resultsgained by finite element method and the load time history obtained bymulti-body system dynamics simulation technology.First of all, the finite element model of sieve plate arc seat is establishedbase on the understanding of the structure and the working principle of coal preparation sieve bend, and the static strength calculation is carried out afterapplying the boundary conditions and loads on it, the results show that thecomponent meets the requirement of strength, at the same time, the stress resultsrequired in fatigue analysis are obtained.Then, the modal analysis is carried out by using the identification methodof ploy reference least squares complex frequency domain method in LMSTest.lab, the mode and natural frequency conducive to vibration are got, and thesieve plate arc seat will be resonant under the excitation by vibration motor withthis natural frequency, so the material particles which blocked in the screen slitare easy cleaned; the mechanical model and the kinematics differential equationof coal preparation sieve bend are established base on Lagrange method, thedisplacement amplitudes of sieve plate arc seat and screen box are calculated,and vibration displacement curves is obtained through the simulation of multirigid body system model created in the ADAMS, these verify the accuracy ofthe model by comparing with the results of theoretical analysis, meanwhile theresults also indicate that the vibration displacement of sieve plate arc seat is fargreater than the screen box, which is propitious to avoiding the slot plugging andreducing the fatigue failure of screen box; on the basis of the multi rigid bodysystem model, the original rigid body of sieve plate arc seat is replaced after thesoften treatment, and the rigid-flexible system model is established, the loadtime history of sieve plate arc seat is exported by the dynamics simulationanalysis in resonance with this model. Finally, using the ANSYS14.5nCode DesignLife to match the stressresults obtained by static analysis and load time history of sieve plate arc seat toform Time-variable stress tensor, combining the S-N curve of the material andMiner linear fatigue cumulative damage rule, the dangerous position with smallfatigue life is got by calculation, its number of cycles is1.963×109, whichmeets the service life requirement of screen machine.In this paper, the finite element method and multi-body dynamicssimulation is applied to the fatigue life of coal preparation sieve bend, the weakplace in sieve plate arc seat is found out, and its fatigue life is obtained, theresults can be used as a basis for the structure improvement and maintenance.The fatigue analysis method not only combines the strength analysis, motionanalysis and fatigue analysis, has the advantages of high reliability and goodapplication, but also reflects the superiority of virtual prototype technology.