Study on impact dynamic characteristics of semi-autogenous mill liner based on improved multivariable method

The impact resistance of semi-autogenous mill liner has an important influence on the reliable operation of the system. The complex dynamic characteristics in the process of collision with abrasive medium are studied by the improved multivariable method proposed in this paper. Firstly, based on manifold element method, the deformation of abrasive medium and lining plate in the contact area is expressed by the coordinates of first-order manifold element basis function, while the deformation of the non-contact region is described by modal coordinates to improve the traditional multivariable method, and the displacement constraint equations as well as the acceleration constraint equations of the collision system are derived, then the Lagrange method is used to establish the impact dynamic equation of abrasive medium and lining plate system. Secondly, a collision test rig between abrasive medium and lining plate was built to verify the correctness and accuracy of the proposed method. Finally, the influence of structural parameters and motion parameters of abrasive medium and lining plate on the dynamic characteristics of collision system is analyzed by parameter analysis method. It is found that when the Poisson's ratio of abrasive medium to lining plate material exceeds 1.0, the increase amplitude of stress becomes smaller. The increase amplitude of displacement, velocity, acceleration and stress at the collision contact point decreases when the initial velocity of abrasive medium exceeds 3.0 m/s. The stress at the collision contact point changes greatly, and the maximum acceleration occurs in advance when the radius of abrasive medium exceeds 20 mm. When the thickness of liner exceeds 40 mm, the time of maximum acceleration to reach is almost unchanged. The results show that compared with the traditional multivariable method, the improved multivariable method can increase the modeling efficiency and solving accuracy, and lay a theoretical foundation for optimizing the structure of the liner and raising the service life of the system.