Numerical Simulation On Stress And Deformation Mechanism Of Ultrasonic Roller Burnishing

Ultrasonic roller burnishing(URB)can be traced back to the 1950s.It is a simple and efficient surface strengthening process.It can reduce the surface defects of parts,strengthen the surface,improve the stress distribution on the surface,and improve the surface quality.Compare with the traditional burnishing,ultrasonic impact,heat treatment and other processes,it has advantages of simple operation,low cost,low pollution,better surface strengthening effect.For large-scale additive parts in the marine industry,the formation of sedimentary layers is often accompanied by complex residual tensile stress distribution and formation of dendritic grain internal structure under the large temperature gradient of the laser cladding process.Subject to the above factors,there are defects in the mechanical properties,surface properties and internal structure of the parts themselves.The ultrasonic roller burnishing performs high-frequency impact forging and continuous rolling on the material cladding layer which has not been cooled,so that the surface layer of the material is plastically strengthened and deformed,forming a better residual compressive stress,improving surface defects and meeting the processing requirements of the work piece.In this paper,the ultrasonic roller burnishing of TC4 titanium alloy is taken as the research object,and the traditional burnishing process is compared.From the two perspectives of analytical research and finite element research,the mathematical model and finite element model of two process processes are established respectively,and the processing mechanism of ultrasonic roller burnishing is studied.The stress,strain and deformation displacement of the materials after the two processes were compared and discussed,and the changes of the surface of the material during the processing and after the processing completed,as well as the actual effects of ultrasonic vibration application were explored.The orthogonal test schemes were designed for several process parameters affecting the processing quality of ultrasonic roller burnishing process.Each process parameter was established by regression analysis and statistical analysis was carried out.The influence of each process parameter and its significance were analyzed.Finally,the composite ultrasonic roller burnishing process with the additive manufacturing is studied,and the influence of overall AM-URB composite process on the change of stress field of the cladding layer was analyzed and discussed.The results show that strengthening processes can change of stress distribution,and can form a beneficial residual compressive stress layer and a surface plastic strengthening layer.Ultrasonic roller burnishing with ultrasonic vibration has better surface strengthening effect.The forging temperature,tool size and ultrasonic amplitude have a significant impact on the process surface stress and deformation.Ultrasonic roller burnishing is applied to the surface of the additive cladding layer that has not been cooled,compared with normal additive manufacture,which improves the surface stress distribution and reduces defects.The research content of this paper provides some theoretical guidance and reference value for the practical application of engineering and the choice of actual process parameters.