| LI Guang-qi,ZHU Gang-xian,ZHAO Liang,WANG Li-fang,SHI Shi-hong.Numerical Simulation on Temperature Field and Stress Field of Cladding Layer by Hollow-Ring Laser[J],49(7):319-328 |
| Numerical Simulation on Temperature Field and Stress Field of Cladding Layer by Hollow-Ring Laser |
| Received:November 20, 2019 Revised:July 20, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.07.040 |
| KeyWord:hollow ring laser residual stress numerical simulation temperature field thermal stress evolution experimental determination |
| Author | Institution |
| LI Guang-qi |
a.School of Mechanical and Electrical Engineering, Soochow University, Suzhou , China |
| ZHU Gang-xian |
a.School of Mechanical and Electrical Engineering, Soochow University, Suzhou , China |
| ZHAO Liang |
a.School of Mechanical and Electrical Engineering, Soochow University, Suzhou , China |
| WANG Li-fang |
b.Engineering Training Center, Soochow University, Suzhou , China |
| SHI Shi-hong |
a.School of Mechanical and Electrical Engineering, Soochow University, Suzhou , China |
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| Abstract: |
| The work aims to study the distribution law of temperature field, stress evolution process and residual stress distribution along the cladding depth direction of hollow ring laser cladding layer based on the process of "hollow beam and inside-beam powder feeding" and provide guidance for regulating or reducing the residual stress of laser cladding layer. APDL language in ANSYS software was used to establish physical model of single cladding layer and simulate the laser loading to obtain the temperature field result by birth and death element. Based on this, the thermo-mechanical coupling was performed, the stress evolution process was analyzed and the path along the depth direction of the cladding layer was established, and the residual stress distribution results were obtained. Finally, the experimental determination was made. The spot temperature distribution was in “saddle” shape and the temperature distribution on the cross section of the cladding layer was in symmetric “W” shape when the hollow-ring laser beam was loaded. At the same time, the temperature of the cladding layer on both sides was high and the intermediate temperature was low. The nodes on the upper surface of cladding layer were heated twice during the laser scanning, and the second peak temperature was higher than the first time. The thermal stress changed continuously in the scanning process, which was transformed form compressive stress generated in the initial cladding process into tensile stress. The residual stress value along the scanning direction was the largest, which was up to 273 MPa, while the largest value at the upper surface was 235 MPa. The minimum value of the bonding surface between the cladding layer and the substrate was 185 MPa. Finally, the numerical calculation was consistent with the experimental results through the experimental determination. The "saddle-shaped" energy distribution of the hollow ring laser spot makes the temperature distribution of the cladding layer more uniform, which can effectively reduce the temperature gradient. The remelting effect of the high temperature region in the rear half of the ring spot facilitates the redistribution of energy and reduces stress concentration. The residual stress distribution in the depth direction of the cladding layer along the laser scanning direction gradually decreases with increasing depth. |
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