移动式抛丸器的抛丸过程演变和机理研究
发布时间：2018-11-21 10:45
【摘要】：本文以LKP550型移动式抛丸机的抛丸器为研究对象,采用离散元软件模拟钢丸在抛丸器中的宏观运动过程,分析钢丸直径、叶轮转速、分丸轮与叶轮安装角度对钢丸抛射速度的稳定性以及大小的影响,为抛丸强化分析确定了抛丸工艺参数的优化范围,随后以Q345钢为例,对钢丸冲击Q345钢后应力和应变的微观过程进行了有限元分析,获得了钢丸直径与钢丸抛射速度对靶材残余应力场分布的影响规律。主要研究结论如下:对LKP550型移动式抛丸机中钢丸在抛丸器内沿分丸轮叶片和叶轮叶片的演变过程以及抛丸强化机制进行了理论分析,获得了影响钢丸抛射速度和抛丸强化效果的主要因素。对抛丸过程中钢丸在抛丸器内的运动过程进行了离散元数值分析,模拟结果表明:叶轮转速对钢丸抛射速度的影响最大,验证了理论分析中叶轮转速与钢丸抛射速度成线性正比的正确性,且钢丸直径和分丸轮与叶轮安装角度是影响钢丸抛射速度的主要因素。钢丸直径、叶轮转速、分丸轮与叶轮安装角度过小会导致钢丸抛射速度的不稳定,叶轮转速过大也会引起钢丸抛射速度的不稳定性。为了保证钢丸抛射速度的稳定性和抛丸效果,选择钢丸直径在Φ0.6mm~Φ2.0mm之间,叶轮转速在2250rpm~2950rpm之间,分丸轮与叶轮安装角度在11°~20°之间,以此作为后续抛丸强化分析的工艺参数。在离散元模拟结果的基础上,选择优化后的抛丸工艺参数,以Q345钢为例,重点研究了Φ0.6mm~Φ2.0mm的钢丸直径和60m/s~80m/s的钢丸抛射速度对抛丸后材料表层应力应变微观过程的影响。结果表明:在相同钢丸抛射速度下钢丸直径对抛丸残余应力场的深度影响较大,在相同钢丸直径下钢丸抛射速度对残余应力的大小影响较大。钢丸抛射速度和直径过小则抛丸强化效果不明显,二者过大会导致材料表层产生拉应力而破坏抛丸强化效果。对于Q345钢,钢丸直径在Φ1.0mm~Φ1.4mm之间,钢丸抛射速度在70m/s~75m/s之间是合适的抛丸强化工艺参数组合。此外,通过离散元对抛丸过程中钢丸宏观运动过程的分析,以及随后在离散元分析的基础上对钢丸冲击Q345钢表面后应力应变的微观分析,发现将离散元方法与有限元方法结合研究抛丸过程的演变和机理具有可行性。
[Abstract]:In this paper, taking the shot blasting device of LKP550 type mobile shot blasting machine as the research object, using discrete element software to simulate the macroscopic motion process of the steel shot in the shot blasting machine, the diameter of the steel shot and the rotating speed of the impeller are analyzed. The influence of the installation angle of pelletizing wheel and impeller on the stability and size of the projectile ejection velocity, the optimum range of shot blasting process parameters was determined for shot peening strengthening analysis, and then the Q345 steel was taken as an example. The microcosmic process of stress and strain in Q345 steel was analyzed by finite element method. The influence of the diameter of steel pellet and the velocity of projectile ejection on the distribution of residual stress field of the target was obtained. The main conclusions are as follows: the evolution process of steel pellets along the pelleting wheel blade and impeller blade and the strengthening mechanism of shot blasting in LKP550 type mobile shot blasting machine are analyzed theoretically. The main factors influencing the ejection speed and the strengthening effect of the steel shot were obtained. The discrete element numerical analysis of the motion of the steel shot in the shot blasting device is carried out. The simulation results show that the speed of the impeller has the greatest influence on the ejection velocity of the steel shot. The correctness of the linear ratio between the impeller speed and the projectile ejection velocity is verified in the theoretical analysis, and the diameter of the steel shot and the installation angle of the splitter wheel and the impeller are the main factors affecting the projectile ejection velocity. The diameter of steel pellets, the speed of impellers and the installation angle of pellets and impellers will lead to the instability of the ejection velocity of the steel pellets, and the instability of the ejection velocities of the steel pellets will also be caused by the excessive rotational speed of the impellers. In order to ensure the stability of the projectile ejection speed and the shot blasting effect, the diameter of the steel shot is between 桅 0.6mm ~ 桅 2.0mm, the rotational speed of the impeller is between 2250rpm~2950rpm and the installation angle of the split-shot wheel and the impeller is between 11 掳~ 20 掳, which is used as the technological parameter of the subsequent shot blasting strengthening analysis. On the basis of the simulation results of discrete element, the optimized parameters of shot blasting are selected, and the Q345 steel is taken as an example. The effects of diameter of 桅 0.6mm ~ 桅 2.0mm steel pellets and 60m/s~80m/s 's projectile ejection velocity on the micro-process of stress and strain in the surface layer of the material after shot blasting were studied. The results show that the diameter of the steel shot has a great influence on the depth of the residual stress field under the same projectile ejection velocity, and the steel shot ejection velocity has a great influence on the residual stress under the same diameter of the steel shot. When the velocity and diameter of steel shot are too small, the strengthening effect of shot blasting is not obvious, but the tensile stress on the surface layer of the material is caused by the excessive assembly of both of them and the strengthening effect of shot blasting is destroyed. For Q345 steel, the diameter of the steel shot is between 桅 1.0mm and 桅 1.4mm, and the ejection velocity of the steel shot is the appropriate combination of the technological parameters of shot blasting between 70m/s~75m/s and 桅 1.0mm. In addition, the macroscopic motion of the steel shot during shot blasting is analyzed by discrete element method, and the stress and strain of the steel shot impacting the surface of Q345 steel are analyzed on the basis of discrete element analysis. It is found that it is feasible to combine discrete element method with finite element method to study the evolution and mechanism of shot blasting process.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG173
本文编号：2346744
[Abstract]:In this paper, taking the shot blasting device of LKP550 type mobile shot blasting machine as the research object, using discrete element software to simulate the macroscopic motion process of the steel shot in the shot blasting machine, the diameter of the steel shot and the rotating speed of the impeller are analyzed. The influence of the installation angle of pelletizing wheel and impeller on the stability and size of the projectile ejection velocity, the optimum range of shot blasting process parameters was determined for shot peening strengthening analysis, and then the Q345 steel was taken as an example. The microcosmic process of stress and strain in Q345 steel was analyzed by finite element method. The influence of the diameter of steel pellet and the velocity of projectile ejection on the distribution of residual stress field of the target was obtained. The main conclusions are as follows: the evolution process of steel pellets along the pelleting wheel blade and impeller blade and the strengthening mechanism of shot blasting in LKP550 type mobile shot blasting machine are analyzed theoretically. The main factors influencing the ejection speed and the strengthening effect of the steel shot were obtained. The discrete element numerical analysis of the motion of the steel shot in the shot blasting device is carried out. The simulation results show that the speed of the impeller has the greatest influence on the ejection velocity of the steel shot. The correctness of the linear ratio between the impeller speed and the projectile ejection velocity is verified in the theoretical analysis, and the diameter of the steel shot and the installation angle of the splitter wheel and the impeller are the main factors affecting the projectile ejection velocity. The diameter of steel pellets, the speed of impellers and the installation angle of pellets and impellers will lead to the instability of the ejection velocity of the steel pellets, and the instability of the ejection velocities of the steel pellets will also be caused by the excessive rotational speed of the impellers. In order to ensure the stability of the projectile ejection speed and the shot blasting effect, the diameter of the steel shot is between 桅 0.6mm ~ 桅 2.0mm, the rotational speed of the impeller is between 2250rpm~2950rpm and the installation angle of the split-shot wheel and the impeller is between 11 掳~ 20 掳, which is used as the technological parameter of the subsequent shot blasting strengthening analysis. On the basis of the simulation results of discrete element, the optimized parameters of shot blasting are selected, and the Q345 steel is taken as an example. The effects of diameter of 桅 0.6mm ~ 桅 2.0mm steel pellets and 60m/s~80m/s 's projectile ejection velocity on the micro-process of stress and strain in the surface layer of the material after shot blasting were studied. The results show that the diameter of the steel shot has a great influence on the depth of the residual stress field under the same projectile ejection velocity, and the steel shot ejection velocity has a great influence on the residual stress under the same diameter of the steel shot. When the velocity and diameter of steel shot are too small, the strengthening effect of shot blasting is not obvious, but the tensile stress on the surface layer of the material is caused by the excessive assembly of both of them and the strengthening effect of shot blasting is destroyed. For Q345 steel, the diameter of the steel shot is between 桅 1.0mm and 桅 1.4mm, and the ejection velocity of the steel shot is the appropriate combination of the technological parameters of shot blasting between 70m/s~75m/s and 桅 1.0mm. In addition, the macroscopic motion of the steel shot during shot blasting is analyzed by discrete element method, and the stress and strain of the steel shot impacting the surface of Q345 steel are analyzed on the basis of discrete element analysis. It is found that it is feasible to combine discrete element method with finite element method to study the evolution and mechanism of shot blasting process.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG173
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