The Study On Dynamic Reliability And Sensitivity With Alternative Model Of Elastic Mechanism Considering Parametric Correlations

With the development of science and technology,elastic mechanism is more and more concerned by mechanical research.It is of great importance to study the accurate modeling of dynamics and improve the accuracy and efficiency of computation.Considering the correlation of parameters makes the model more practical,and gradually become a research direction of simulation.The paper,in view of the elastic four-bar linkage and using MATLAB as a tool,respectively establishes an accurate kinetic model and Kriging substitution model.Considering the randomness and correlation of the parameters,the reliability and sensitivity of the system are analyzed.The main works are as follows.Firstly,First of all,based on beam element,a differential equation of unit motion is established by using type function and generalized coordinates.The motion differential equation of system is obtained by coordinating matrix and coordinate transformation matrix and Lagrange equation.Then the elastic deformation of the middle point of the crank and connecting rod and the first three order natural frequencies of the system are studied.Secondly,when the parameters have a certain value,a precise dynamic model of elastic four bar linkage is established,and the influence of the change of the speed of the driving rod on the maximum stress value is analyzed.In the same time,taking the rigid output angle of the mechanism as an example,it calculates and analyzes the reliability and sensitivity of output angle by Monte Carlo.Then,when having random parameters,based on the exact response values of the sample points,the Kriging substitution model is established,and its accuracy and efficiency are verified.An alternative model of elastic displacement and maximum dynamic stress of the system is established.Monte Carlo method is used to calculate and analyze its reliability and sensitivity of each parameter.Finally,considering the correlation of the parameters,the reliability and sensitivity of the elastic four-bar linkage are studied in this paper.The correlation variables and Copula functions were used to obtain the relevant variables.The dynamic stress was obtained by the substitute model.The reliability and sensitivity were calculated by Monte-Carlo method.The influence of the variation of variables on the reliability and sensitivity was analyzed.In this paper,an alternative model is introduced to analyze the dynamic model and characteristics of a flexible four-bar linkage.It also studies the reliability and sensitivity with parametric correlations.The purpose is to improve the computational efficiency of modeling and to analyze the sensitive factors affecting reliability and the influence of the parametric correlations.