Numerical Simulation Of Shot Peening Of TC4 Titanium Alloy

The failure mode of aviation titanium alloy components is mostly fatigue failure,and the fatigue performance is often related to the surface quality of the workpiece.In order to improve the fatigue life of components,surface strengthening is usually carried out.As a surface cold treatment method,shot peening can effectively prevent crack initiation and improve the fatigue strength of metal parts.Taking TC4 titanium alloy as the research object,this paper studies the effects of target surface morphology and initial roughness on residual stress,dislocation cell size and roughness in shot peening numerical simulation through multi shot peening numerical model based on random probability control,dem-fem coupling shot peening numerical model and laser shot peening model,and tries to apply neural network to shot peening simulation,It gives a feasible reference for reducing the time of numerical simulation.1)Based on the three-dimensional shot peening finite element model of probability controlling the impact position of multiple shots on the target surface,the interaction between shots in the process of shot peening strengthening is controlled by probability,and the two working conditions with shot peening angles of 60° and 90°are simulated;In the process of achieving complete shot peening coverage,with the increase of the number of shots,the residual compressive stress increases gradually and tends to be stable,while the roughness of the sprayed surface increases linearly;Under the condition of full shot peening coverage,compared with the condition of 60° shot peening angle,the surface residual compressive stress under the condition of 90° shot peening angle is small,but the maximum residual compressive stress is large,and the surface roughness is also large.2)The finite element models for shot peening strengthening of concave and convex surfaces with different curvature radii are established,the DEM-FEM coupling simulation method is developed,and the influence of material surface morphology on the effect of shot peening strengthening of TC4 titanium alloy is explored in combination with the dislocation density evolution model.The results show that the concavity and convexity of the sprayed surface and its radius of curvature have a significant effect on the residual compressive stress,grain refinement and surface roughness of TC4 titanium alloy strengthened by shot peening.3)The autocorrelation function based on Gaussian distribution is established to characterize the real surface roughness of parts.The influence of shot peening parameters on residual stress under different surface roughness is studied by dem-fem coupling simulation.Shot peening can reduce the surface roughness of TC4 titanium alloy parts with large roughness.With the increase of shot peening coverage,the residual stress of shot peening also increases,and the maximum residual stress of vertical shot peening is larger.4)The calculation framework of the combination of constitutive model based on dislocation mechanism and dislocation density evolution model is established and applied to ABAQUS/Explicit program to numerically simulate the residual stress and grain refinement caused by laser peening of TC4 titanium alloy.With the increase of laser overlap rate,the residual compressive stress increases and the dislocation cell size decreases.Neural network is used to predict the residual stress and grain size of TC4 titanium alloy blade,so as to reduce the cost of numerical calculation of large workpiece.Figure[59]Table[4]Ref[107]...