龚曙光,冯应朗,卢海山.超高速激光熔覆影响细长活塞杆弯曲变形的仿真分析与试验[J].表面技术,2024,53(19):117-125.
GONG Shuguang,FENG Yinglang,LU Haishan.Simulation Analysis and Experiment on Bending Deformation of Slender Piston Rod Influenced by Extreme High-speed Laser Material Deposition[J].Surface Technology,2024,53(19):117-125 |
| 超高速激光熔覆影响细长活塞杆弯曲变形的仿真分析与试验 |
| Simulation Analysis and Experiment on Bending Deformation of Slender Piston Rod Influenced by Extreme High-speed Laser Material Deposition |
| 投稿时间：2023-10-06 修订日期：2023-12-13 |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.19.011 |
| 中文关键词: 超高速激光熔覆 细长活塞杆 温度 应力 变形 |
| 英文关键词:extreme high-speed laser material deposition slender piston rods temperature stress deformation |
| 基金项目:国家自科基金(51875493);湖南省研究生科研创新项目(QL20220150);湖南省自然科学基金项目(2021JJ40537) |
| 作者 | 单位 |
| 龚曙光 | 湘潭大学，湖南 湘潭 411100 |
| 冯应朗 | 湘潭大学，湖南 湘潭 411100 |
| 卢海山 | 湘潭大学，湖南 湘潭 411100 |
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| Author | Institution |
| GONG Shuguang | Xiangtan University, Hunan Xiangtan 411100, China |
| FENG Yinglang | Xiangtan University, Hunan Xiangtan 411100, China |
| LU Haishan | Xiangtan University, Hunan Xiangtan 411100, China |
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| 中文摘要: |
| 目的 针对细长活塞杆在超高速激光熔覆过程中产生变形的问题，开展热-结构耦合的数值模拟和试验研究。方法 采用高斯热源和单向耦合方式，建立细长活塞杆超高速激光熔覆的热-结构耦合仿真分析模型，探讨活塞杆在不同功率和扫描速度下瞬态温度和应力分布的演化过程。构建超高速激光熔覆细长活塞杆变形的试验测试方案，提出9组激光熔覆工况参数，并将试验测试结果与有限元仿真进行对比。结果 在激光功率相同时，熔池形貌随扫描速度的增大而发生变化，其等温线呈现彗星状，活塞杆表面上的温度变化曲线要经历3个峰值，然后冷却至室温，最后趋于稳定。熔池区域的等效应力值最大，且会随激光光源的轴向移动而发生演化，而涂层与基体结合界面处的等效应力在极短时间内会经历先升后降的多次循环，然后趋于稳定。沿活塞杆轴向的等效应力呈现两端高、中间低且顶尖端最大的趋势，等效应力值均随激光功率的增加而增大，其应力差值与活塞杆的变形量相对应。当功率为3 500 W、扫描速度为25 m/min时，应力差值最小，且变形量也最小。结论 热应力是引起活塞杆轴向应力分布变化的主要影响因素，轴向等效应力的差值决定着活塞杆变形量的大小，所得结论可为细长轴类零件表面处理的超高速激光熔覆工艺参数选取提供指导。 |
| 英文摘要: |
| Extreme high-speed laser material deposition (EHLA) has become a hot research issue in the surface treatment technology of shaft parts. Aiming at the deformation of slender piston rods during the extreme high-speed laser material deposition process, experimental study and numerical simulation of thermal-structure coupling were carried out. According to the Gaussian heat source and unidirectional coupling method, a thermal-structure coupling model by EHLA of slender piston rods was established to investigate the evolution process of the transient temperature field and stress distribution under different laser power and scanning speed. Firstly, the experimental test scheme of extreme high-speed laser material deposition on slender piston rod deformation was constructed, 9 groups of laser cladding parameters were proposed. And then, the experimental test results were compared with the finite element simulation. The results showed that with the same laser power, the molten pool morphology changed with the increase of scanning speed and the isotherm at the end of the molten pool presented a comet-like shape. The temperature curve on the surface of the piston rod reached three peaks, and then became stable after cooling to room temperature. The peak temperature increased with the increase of laser power. The equivalent stress value in the molten pool region was the largest and would evolve with the axial movement of the laser source. The equivalent stress at the interface between the coating and the substrate would go through several cycles of first rising and then falling in a very short time and then tend to be stable. The equivalent stress along the axial direction of the piston rod showed the trend of high at both ends, low in the middle and maximum at the top tip, and the equivalent stress values increased with the increase of laser power. The change law of the stress difference in 9 cladding conditions corresponded to the deformation of the piston rod, and the stress difference and deformation amount were the smallest when the power was 3 500 W and the scanning speed was 25 m/min. Therefore, the thermal stress is the main factor that causes the stress distribution along the axis of the piston rod, and the difference of the equivalent stress along the axis of the piston rod determines the deformation of the piston rod. With the elastic-plastic deformation about the slender piston rods, the observations are important and necessary during experimentation and the numerical simulations. According to the analysis of the results, it is found that the axial bending deformation of the slender piston rod is related to the magnitude of the axial stress difference. This analysis reveals that greater disparities in axial stress correspond to increased bending deformation. Most importantly, in situations characterized by external loading and continuous thermal stress coupling, the von-Mises stress pattern of slender piston rods displays a discontinuous behavior. Crucially, the pressure differential between the cladding layers on both flanks and the central region directly influences axial bending deformation of the slender piston rod. The conclusions can provide guidance for the selection of extreme high-speed laser material deposition process parameters for the surface treatment of slender shaft parts. |
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