Study On The Flexible Multi-body Dynamics Analysis Method Of Belt Conveyor

A systematic study on the flexible multi-body dynamics analysis method for belt conveyor is made, establishing dynamic model of conveyor belt based on rigid finite element method with absolute coordinate, contact-impact dynamic model between conveyor belt and drum based on continuous impact force method, indentation rolling resistance analysis model between conveyor belt and idlers based on boundary discrete method and integrated flexible multi-body analysis model of belt conveyor in this dissertation.Applying nonconservative systems Lagrange equations of the second kind, dynamic differential equations of rigid element are derived and the dynamic equations of rigid-flexible multi-body system are established using unidirectional recursive synthesis method. Improving the classical rigid finite element method and proposing rigid elements of system as study objects uniformly, the coordinate systems fixed on mass centre of rigid elements are assigned. The positions of rigid elements are described with Cartesian coordinates of the original points, and the orientations are described with the Euler angular coordinate. Introducing the constrain equations and applying nonconservative system Lagrange equations of the first kind in the form of energy, the dynamic differential equations of the rigid- flexible multi-body system are derived. On the basis of these, the rigid finite element method using absolute coordinate is developed.Combining normal contact force based on the continuous impact theory and tangent friction based on Coulomb friction law, the contact-impact dynamic model between conveyor belt and drum is proposed and then the multi-body contact dynamics equations are established. Considering the contact-impact problem between conveyor belt and drum as non-ideal unilateral constraints, the criterion of dynamic contact problem is established by using the complementarity conditions for linear programming problem. According to the theory of varying topological structure, the varying topological dynamic problem due to contact-impact is translated into unvarying topological dynamic problem including time-varying contact force. Thus, the multi-body dynamics equations of the belt conveyor with varying topological configuration are established and solved.By using the differential constitutive equation of standard linear solid model for characterizing the viscoelastic properties of belt, and introducing Fourier series for describing displacement and stress of contact area between conveyor belt and idlers and to obtain flexibility matrix, on the basis of these the boundary discrete equations are established for reflecting the relationship between displacement and stress of boundary nodes in contact area to realize the computer simulation analysis for indentation rolling resistance. Here a verification example is given to verify the validity of this method.3D modeling method of belt conveyor by use of the rigid finite element method based on absolute coordinate is discussed. Aimed at the difficult problem of belt element's length selection, the varying length of belt elements are put forward. The simulation software for the dynamic performance of belt conveyor is developed. The field testing to a belt conveyor validates not only the dynamic simulation results obtained from the software, but also the correctness of the dynamic modeling method presented in this dissertation. Through the simulation under various starting velocities, the influence of starting process on belt conveyor dynamic performance is studied.58 figures, 4 tables and 185 references are included in the dissertation.