Dynamic Model And Analysis Method Of Elastic Mechanism Systems With Damping Alloys Parts And Its Industry Application

With the development of modern mechanical industry, fatigue destruction and precision decrease due to elastic vibration occur much frequently because machine operation speeds became faster and faster and the parts of machines are designed lighter and lighter. How to reduce vibrations of the mechanism systems simply and reliably and how to improve precision and fatigue life time of the machine are important in theory and practice of mechanical engineering, so dynamic models and analysis methods of elastic mechanism systems considering damping effects are necessary. Oscillator mechanism with four-eccentric axes is widely used in modem continuous casting machine. With the increase of operation speeds of the machine, elastic vibrations of the machine parts became much obviously. In order to design the machine reasonably, the complex dynamic property of the system must be studied deeply. The main research works and conclusions of this thesis are listed as follows.The dynamic analysis model of elastic mechanism system with damping alloy parts is deduced based on the relationship between stress and strain of the material, also the analysis model under viscous damping model, complex damping model, nonlinear damping model and viscous-elastic damping model is put forward using the finite element method. Dual principle is discussed while complex constitutive theory is used. The numerical solution stability of differential equations with complex damping is analyzed. A beam element of 2 nodes and 10 degrees of freedom with interlayer damping alloy is presented and the element differential equation of motion is put forward.A state space model for parts of non-linear oscillation systems is put forward, and the concealed analytical solution for the systems is deduced. A numerical calculation method is presented and the calculation precision is improved greatly through using iterative method. Finally the presented numerical method is extended to solve differential equations with complex stiffness matrix. Compared with traditional numerical methods such as Houbolt Method, Wilson-0 Method, and Newmark-p Method,A Dissertation Submitted to Xi'an University of Technology for Degree of Doctor Philosophythe presented numerical method has higher calculation precision and efficiency. The astringency, error and stability of the numerical method are researched. Zero matrix method, constant matrix method, and Jacobian matrix method are constructed in order to improve numerical precision and efficiency. The steps for calculating matrix exponential function using Pade approach method are given out.The damping values of damping aluminum-alloy and zinc-alloy are measured. Nonlinear laws between damping value and strain of damping alloy are obtained by mean of experiment and numerical fitting. Base on the experimental data some damping models such as conic model, inverse hyperbola model, exponent model, inverse exponent model, dislocation-induced damping model are put forward, and the results between numerical calculations base on above models and experiments are studied contrastively. The vibration absorption effects of damping aluminum-alloys, zinc-alloys and damping alloy interlayer beam are tested through a four bar linkage mechanism and the test results are carried out a contrastive research with numerical analysis results, and it is found that response curves obtained by test are similar with those given out by numerical calculation. Contrastive tests of damping aluminum-alloys, zinc-alloys and 45# steel are carried out at the case of equal stiffness. The test results show that when the rocker bar is made of damping aluminum-alloys or damping zinc-alloys, the strain amplitude at the middle point of connecting bar is half of the one when the rocker bar is made of 45# steel.The mechanical and mathematical models for the kineto-elastodynamic analysis of a multiple linkage oscillator mechanism with four-eccentric axis used in continuous casting machine are presented, which consider both the geometrical non-linearity and lo...