Friction Model Theory And Experimental Research

In engineering application,in view of the phenomenon that the slender members under axial compression are easy to lose stability,the limiting unstable members are applied to theoretical research and practical engineering as an effective measure.Through a large number of practice,it is shown that the casing component is widely used as a limiting instability component.The casing structure is composed of the core and the sleeve,and there is a certain gap between the core and the sleeve.In the work of the casing component,the core is subject to axial pressure and buckling deformation occurs,and the sleeve increases the bearing capacity of the component by constraining the buckling deformation of the core.In the process of stress,the end structure of the core and the sleeve may buckle in advance and reduce the bearing capacity of the component Therefore,the research of the end structure is one of the important research directions of the casing component.The finite element software ABAQUS is used to simulate the end strengthening structure of the casing component.The comparison between the simulation results and the experimental results of the end strengthening structure of the casing component in reference [1] shows that there is a certain difference between the simulation results and the test results.Through the analysis of the stress process of the casing component,it is found that the main reason for the difference between the two results is the bending of the core and the sleeve defined by ABAQUS The classical friction model,Coulomb friction model,is used in the curved contact friction model.The influence factors of Coulomb friction are few.The Coulomb friction model can not accurately simulate the buckling contact friction behavior between the core and the sleeve when the casing is constructed under the axial pressure,which leads to the results of the experimental research and the finite element simulation in the study of strengthening the structure of the end of the casing component So a contact friction model suitable for buckling deformation of Q235 and Q345 steel is very important.Based on this,this paper mainly studies the friction model between Q235 and Q345 steel,which considers the influence factors of friction pair material and size,normal pressure,relative sliding speed of friction pair,and mainly completes the following work.1?The classical friction model,such as Coulomb friction model,is introduced.Based on the classical friction model,scholars at home and abroad consider more relevant factors under the corresponding engineering conditions,and put forward a more accurate friction model through theoretical and experimental research.In this paper,the theoretical analysis is carried out firstly,and the research method of this paper is chosen as the experimental research.Then,it analyzes which factors have a great influence on the friction model in the actual situation.Combined with the research ideas of the existing friction model,the experimental research of the friction model in this paper is carried out.Taking Q235 and Q345 steel plate as the research object,the material and size of the friction pair,the normal pressure and the relative sliding speed of the friction pair are taken into consideration.The factors affecting the temperature,surface roughness,friction surface and surface film are treated uniformly in the same way to ensure that the test process and result will not be greatly affected.The two plates are systematically studied.Sliding friction.2?According to the theoretical analysis of the friction model and the purpose of the friction model test,combined with the experimental equipment conditions of Guizhou University Laboratory,the structure of the casing component is simplified.The core and sleeve are simplified into two steel plates,the steel plate material is Q235 and Q345,the thickness of the inner steel plate is 8mm,10 mm and 12 mm,and the outer steel plate is 20 mm.Six orthogonal experiments are carried out to study the buckling deformation and the outer of the inner steel plate In the process of the friction behavior of the upper and lower steel plates in the interface contact,the friction,pressure and relative sliding speed of the internal and external steel plates at different positions of the interface contact are measured;the test data are analyzed and processed,and then the friction model in this paper is optimized and fitted with the fitting software 1stop,and the Q235 and Q345 steel plates are taken as the friction pairs The maximum static friction model with the material and size of the friction pair and the normal pressure as the influencing factors;the friction model with the material and size of the friction pair,the pressure and the relative sliding speed of the internal and external steel plates as the influencing factors;on this basis,further considering the influence of the relative position,optimize and match a phase with the material and size of the friction pair,the normal pressure,the relative position and the internal and external steel plates The friction model with sliding speed as the influencing factor.3?Two groups of simplified models of casing components are designed.The simplified model of casing components is simulated and analyzed in ABAQUS by using Coulomb friction model,friction model in this paper and the case of minimum friction coefficient.The relationship between the axial force on the inner steel plate and the axial displacement of the inner steel plate,the relationship between the axial force on the inner steel plate and the friction between the inner steel plate and the outer steel plate,the relationship between the axial force on the inner steel plate and the axis of the central point of the inner steel plate and the outer steel plate are obtained The results show that the friction model has a great influence on the study of the buckling friction contact behavior between steel plates,and in the process of friction,the friction,relative displacement,axial force and other physical parameters have the same trend of change in the whole There are some differences,but the friction model in this paper considers more factors,which shows that the friction model in this paper is more suitable for the study of the buckling friction behavior between Q235 and Q345 than the Coulomb friction model.