Research And Numerical Simulation Of Friction Surfacing For Composite Axial Vibration

Friction surfacing(FS)is a solid state technology with increasing application in the context of localized surface engineering.Fs has been investigated mainly for producing fine grained coating,which exhibit superior wear and corrosion properties.Since no bulk melting takes place,this process allows dissimilar joining of materials that would be otherwise incompatible or difficult to deposit by fusion based methods.Several studies also emphasize its energy efficiency and low environmental impact as key advantages,When compared with other alternative technologies.Main application include repair of worn or damaged surfaces through building up or crack sealing.A wide range of material combinations have been deposited by FS,mainly alloy and stainless steels.Aluminium,magnesium and titanium alloys have also been investigated,including the production of metal matrix composites.Starting with a brief introduction,this thesis summarizes the development of research which some domestic and foreign scholars did about friction surfing.An overview of the main technologic and equipment advances is presented,including:computational optimization models,surface preparation,gas protection,post-processing methods,pre-heating and cooling.An assessment of the material deposition rate and the specific energy consumption is also provided,comparing friction surfacing to others.According to the previous research results,the friction surfacing of composite axial vibration was put forward.According to the characteristics of stress distribution and the theory of friction heat generation in friction surfacing,a suitable mathematical model of temperature field by moving heat source is established.At the same time,two-dimensional and three-dimensional models were used to simulate the temperature field and stress-strain field with coupled thermo-mechanical analysis in the initial stage of the process.In the two-dimensional model analysis,the axial amplitude of the axial pressure was controlled to add the axial vibration of the consumable rod.It was found that adding vibration can effectively reduce the value of the axial pressure required.In the three-dimensional model analysis,the modal analysis of the welding system was carried out by using the vibration theory,and the first five order natural frequency and displacement cloud image of system were calculated.The numerical simulation of 2D and 3D models provides basic data to support for the design of welding equipment and the development of friction surfacing.Friction surfacing has a significant potential for further industrial application and is being developed as a practicable alternative to mainstream coating process and the production of metal matrix composites.