Numerical analysis and experimental validation on residual stress distribution of titanium matrix composite after shot peening treatment

• SP process on composite is simulated by 3D finite element dynamic analysis.
• Both 3D homogeneous and inhomogeneous models are set up during SP process.
• Tensile residual stresses and CRS appear in reinforcement and matrix respectively.
• Stress distribution keep adverse stress in reinforcement and retard damage to matrix.
• Residual stress distributions by experiments agree with the simulation results.

The residual stress distribution introduced by shot peening (SP) in the deformed surface layer of titanium matrix composite (TiB+TiC)/Ti-6Al-4 V was investigated via three-dimensional (3D) finite element dynamic simulation and experimental validation. The program of ANSYS/LS-DYNA was utilized in the 3D finite element dynamic analysis of SP process, and the 3D homogeneous and inhomogeneous models were set up. The results showed that the compressive residual stresses (CRS) were introduced in the matrix, but the tensile residual stresses appeared in the reinforcements. The maximum CRS and tensile residual stress were -1511 and +1155 MPa respectively, which revealed the higher yield strength of reinforcements. This type of stress distribution revealed the effect of reinforcements, keeping the adverse tensile stresses in the reinforcements and retarding the damage to the matrix during deformation. In terms of experiments, after SP, the residual stresses along the depth from the surface were measured using X-ray diffraction (XRD) method. The experimental results indicated that the CRS formed in the surface layer and the maximum appeared on the subsurface. The range of residual stresses found in experiments supported the simulated results, which verified the validity of 3D finite element dynamic analysis.