Theoretical Study And Application For Dynamic Designs Of Foundations Of Giant Paper Machines

Paper-making industry is one of the important basic material industries in national economy. In recent years, several giant paper equipments have been imported from abroad, in which the giant paper machines are the key components. The paper machine is suffered to great dynamic loads in operation, so the dynamic design and research of the foundation of paper machine are very important tasks. Based on a practical subject, the dynamic analysis is carried out primarily in this paper, which is of great benefit to the engineering application.Using the finite element method, the dynamic stiffness of the single pile and group piles are calculated, and the comparison of the present results with ones in the《Dynamic Machine Base Design Specification》is made. Since the method in《Dynamic Machine Base Design Specification》is based on the mass-spring- damping model. The results from FEM shows that the stiffness and the damping of foundations with the characteristic of the frequency dependence and the stiffness and the damping calculated according to《Dynamic Machine Base Design Specification》can be used in engineering practices.In this paper, the stiffness of the pile foundation and damping is firstly calculated, and accordingly the dynamic analysis of the pile foundation-machine system of the giant paper machine is investigated by adopting the substructure method. Then the basic step of the dynamic analysis and the way to model the foundation of the vibration system and the load are primarily and elaborately introduced. Based on the spectrum response curve obtained form the modal and harmonic analysis of the vibration system, the basic paper-making machine model meeting the manufacturing company's dynamic requirement on the machine is reasonably designed.At last some problems in the dynamic analysis are discussed, which include the simplification of the basic model, the determination of the damping matrix of the finite element model and the dynamic approach of some specific components of paper machines. The treatment methods of such problems have been utilized in the dynamic designs of several practical subjects. The engineering practice shows that the dynamic analysis scheme in this paper can be used for the dynamic designs of foundations of paper machines.