Unlike DEM based on minimum potential energy variational principle of finite element method, but based on the fundamental Newton's second law, its basic idea can be traced back to the ancient force analysis method, any of an object as a separate body to analyze the forces and moments always been adjacent objects role, it is in its force and moment of action, resulting in deformation and movement, this way of thinking is very easy to implement on a computer, as the force per unit body, after establishing its explicit equations, according to Newton's second law and a combination of different constitutive Changzhou vacuum pump and a differential method to solve the iterative calculation, combined with animation techniques, can visually reflect changes in the system for each unit movement The force field, displacement field, velocity field and other mechanical parameters change, and this method is not the system limits the number of objects. DEM establish constitutive relationship model using a rotor system dynamics model and between units.

Force journal and bearing between the rotor and the housing having the same constitutive relation, that have been simplified to a pair of normal and tangential spring dampers where one's a Cs and Ks and a tangential sliding friction device spell. Worthy of note, the spring damper Ks Cs and sliding friction is a joint action of the fight. When the cut between the two units is greater than the friction force, which occurred between the two units relative sliding, sliding friction device then acts spring damper does not work; otherwise, the spring-damper work, sliding friction does not From mechanics model and its constitutive relation effect; in addition the role of the journal and the bearing unit, when the minimum film gap is greater than zero or greater than a certain value it that the film is not damaged.