| SHENG Xiangfei,TAN Huiyong,YUAN Wenzhi,GOU Jianglong,LI Zhi.Effect of Laser Shock Induced Stress Waves on Formation of Residual Stress Holes[J],53(19):153-163 |
| Effect of Laser Shock Induced Stress Waves on Formation of Residual Stress Holes |
| Received:October 31, 2023 Revised:March 04, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.19.014 |
| KeyWord:laser shock stress wave residual stress stress hole finite element analysis nickel-based superalloy |
| Author | Institution |
| SHENG Xiangfei |
School of Mechanical Engineering,Hunan Hengyang , China |
| TAN Huiyong |
School of Mechanical Engineering,Hunan Hengyang , China |
| YUAN Wenzhi |
School of Mechanical Engineering,Hunan Hengyang , China |
| GOU Jianglong |
School of Mechanical Engineering,Hunan Hengyang , China |
| LI Zhi |
School of Civil Engineering, University of South China, Hunan Hengyang , China |
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| Abstract: |
| In order to reveal the mechanism of the influence of laser shock induced stress waves on the formation of residual stress holes, the propagation process of laser shock induced stress wave were captured, and its characteristics were analyzed, by extracting node stresses at different times, based on the finite element dynamic simulation analysis. The results showed that within 2 000 ns, the initial stress of the material in the area affected by the light spot was only disturbed by the Class Ⅱ stress wave induced by laser shock, and the disturbance gradually stabilized over time; The initial stress disturbance caused by Class Ⅱ stress wave was gradually weakened from the center of the light spot outward, the amplitude of stress fluctuation caused by it decreased from 2 459 MPa to 224 MPa (the amplitude of stress fluctuation in the central region exceeded the yield strength of the material itself); In cases where other process parameters were the same, the residual stress hole phenomenon became more pronounced with the increase of peak pressure and pulse width (the stress amplitude difference σk increased from 0 MPa and 114 MPa to 454 MPa and 568 MPa, respectively, and the stress hole diameter dk increased from 0 mm and 0.8 mm to approximately 1.4 mm in the hole area). The influence of spot diameter on residual stress hole phenomenon was relatively weak . Under the action of 3 J laser energy, there was a stress hole in the residual stress result corresponding to the spatial Gaussian distribution, and σk and dk were 190 MPa and 1 mm, respectively. By increasing the laser energy of the spatial flat top distribution to 7 J, the corresponding residual stress result changed from no stress holes at 3 J laser energy to an obvious stress hole, σk and dk were 634 MPa and 1.4 mm respectively, and the characteristic values of stress holes were greater than the spatial Gaussian distribution under the same peak pressure condition; In addition, under the action of 3 J laser energy, the stress hole corresponding to material 1 was the most significant, σk and dk were 207 MPa and 1.4 mm, respectively, which were higher than those of material 2 and material 3, and even exhibited secondary stress hole. The characteristic related to stress hole σk under the geometric conditions of convex circular surface, flat and concave circular surface were 212 MPa, 190 MPa and 83 MPa, respectively, and dk were all 1 mm. In conclusion, under the action of circular spot laser shock load, the stress waves formed during the loading and unloading processes have a strong convergence effect at the center of the spot, resulting in continuous positive and negative yielding of the material in the center area of the spot, and the formation of residual stress holes; Under the same parameter conditions, the higher the laser energy, the lower the mechanical properties of the material, the stronger the stress wave disturbance action, and the more obvious the residual stress hole phenomenon. In addition, different surface geometric features mainly affect the stress amplitude difference in the hole area. |
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