| As a key component of aero-engine and gas turbine,the blade is required to have excellent fatigue resistance performance,foreign object damage resistance performance and high reliability under extreme service conditions such as high speed,high pressure and high load.Laser shock peening technology is an excellent material surface enhancement technology.The remarkable benefit has been widely recognized by scholars across the world,and has been successfully applied to the important parts including blades.In order to reduce the deformation of blade caused by laser shock peening and improve the dimensional accuracy of blade,it is necessary to carry out in-depth study on the blade processing technology to achieve the purpose of controlling deformation and improving the comprehensive performance of the blade.Based on the ABAQUS finite element simulation platform and experimental research,this paper studies the enhancement effect and deformation of the simulated blade from laser parameters,process methods,and provides reference for blade processing.The basic process of ABAQUS finite element simulation platform applied to laser shock is introduced.The propagation of shock wave in thin-walled parts and development of plastic strain are analyzed.The effect of different pulse widths,impact times,peak pressures,shapes and size of the spot on the development of residual stress distribution in the model are studied.As the pulse width,the number of impacts,and the peak pressure increase,the maximum residual compressive stress increases,and the magnitude of the residual compressive stress increases at the same depth.Under the same impact parameters,the maximum residual compressive stress generated by the larger spot is larger than the small spot.Under the same process parameters,the laser beam with circular spot(2.5mm diameter),square spot(2.5mm side)and elliptical spot(short axis 2.5mm)are investigated.The results show that the residual stress caused by the square spot is the largest,elliptical spot has moderate stress magnitude,and the circle spot has smallest stress magnitude.Under the condition of flat-top spot overlap impact,the effects of different overlap rate and shock times on the residual stress distribution are analyzed.In the case of 30% overlap,some regional stress fluctuations are greater than that of 50% overlap rate,while in some areas the stress fluctuations are less than 50%.When multiple impacts are performed,the stress fluctuations are increasing and the stress distribution uniformity is worse.The effects of the number of impacts,the overlap ratio,the spot shape and the peak pressure on the surface roughness Ra are investigated.The surface roughness of the parts under different processes is calculated by collecting the plastic deformation depth,and then comparative analysis is carried out.When the circular spot with overlap rate of 30%,40%,and 50% are performed,the roughness increases at the beginning and then decreases.When the same overlap rate and different spot shape are used,the roughness under the square spot impact is larger than that of the circular spot.The effects of variable/non-variable pulse width and different constraint modes on deformation are studied.The deformation induced by variable pulse width laser shock is smaller than that of the non-variable pulse width laser shock.By employing the full constraint of the bottom surface,the part has almost no macro deformation.By employing two points constraint at both ends of the part,the macro deformation is small.The macro deformation is the largest when the part under the cantilever constraint condition.The titanium alloy thin-walled simulated blade after laser shock peening possess 368.8 MPa residual compressive stress.The surface roughness is Ra 0.34?m.At the same time,laser shock processing increases the microhardness of the surface of the material by 26.5 %... |
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