Research On DEM-FEM Algorithm For The Coupling Dynamic Properties Between Particles And Elastic Plate

The interaction between particulate matter and engineering structure is widely existed in industrial and agricultural production and can be classified as the coupling problem between discrete medium and continuum.Particulate matter shows complex dynamic characteristics under the action of motion structure.The motion structure also shows obvious nonlinear dynamic characteristics due to the mutual contact with particles.At present,the research in this field mainly focuses on the movement of particulate matter,the dynamic behavior of the elastic structure in the granular medium needs to be further studied.In this paper,A DEM-FEM coupling numerical method using displacement superposition and expansion element is proposed to study mixing efficiency and dynamic response of the blade in particle mixing system.And a coupling calculation method between discrete element and finite element based on secondary development of ABAQUS is tentatively explored.The main work and achievements of this paper are as follows:(1)Based on discrete element method and finite element dynamic algorithm,the expansion element of thin plate is introduced to establish the mechanical parameters relationship of DEM-FEM coupling interface and the dynamic response of the elastic plate in granular media is calculated.The results show that particle size and depth are the two main parameters that influence the dynamic response of the elastic plate embedded in particles.The nonlinear phenomenon such as jump,frequency multiplication,period doubling are observed in dynamic response of elastic plate embedded in particle medium.These phenomena are in good agreement with the related experiments and validate the effectiveness of the coupling algorithm.(2)Based on the DEM-FEM coupling calculation method with extension element proposed above,the finite element model of thin plate is established by commercial software and imported by general format.The fast calculation of dynamic response and accurate orientation of large rotation displacement are achieved by overlaying the vibration response on rotation rigid displacement of the blade.The synchronously calculation of mixing efficiency and blade dynamic characteristics of particle mixing system is realized.The results show that the filling rate,blade position,stirring speed and other parameters are the dominant factors that determines the efficiency of mixing by influence the particle movement in different stages.The blade shows obvious nonlinear vibration during the mixing process,but the vibration of blade have no prominent influence on mixing efficiency.(3)In order to make the most of mature finite element method technology,the secondary development of ABAQUS is used to implement DEM-FEM coupling calculation.Node sets,loads,amplitudes,and time history outputs including displacement sensors are created during the finite element model preprocessing.The displacement of the finite element node is obtained and the particle equivalent load is applied to the node of the finite element model by VUAMP subroutine.The read-write thread control method is used to realize the time synchronization and dynamic interaction of discrete elements and finite element modules in the coupling process.