非光滑表面加工机器人建模及热辊压工艺研究

摘要

针对油气管道内壁涂层减阻结构加工问题，提出一种能在管道内壁涂层表面加工出仿生非光滑表面减阻结构的方法。建立管道内壁辊压加工机器人结构模型，对双凸轮组件运动情况进行动力学分析，结合材料的流动特性，分析聚合物涂层材料在玻璃态转化温度附近的流动特性，建立聚合物黏弹性数学模型，利用黏弹性模型描述聚合物涂层的流变行为，采用数值模拟方法，研究热辊压过程中控制参数对热辊压后表面质量的影响，在辊压速度为0．5、1．0、1．5 rad／s三种情况进行辊压实验。结果表明：聚合物材料的流动变形量在保持温度不变的情况下，随着时间的增加而增加，在结束时刻，涂层凹坑形貌的回弹现象伴随着温度的降低而停止；在恒定辊压速度下，聚合物涂层凹坑的复制率随温度的升高而增大，温度较高时，蠕变速度加快，在辊压温度为150℃的2T／3时刻，聚合物涂层凹坑的形貌效果最佳，在辊压温度较低时，延长保压时间可达到相同的填充效果；在辊压速度为0．5 rad／s时，辊压后凹坑形貌与理想凹坑形貌最为接近，表现出较好的聚合物时间依赖性。%Aiming at processing issue of drag reduction structure of oil and gas pipeline inner wall coating,a method of processing the drag reduction structure with bionic non-smooth surface on the coating surface of inner wall of pipeline was proposed.A structural model of roll processing robot on inner wall of pipeline was established,and the movements of a double-cam component were analyzed. Combined with flow characteristics of material, the flow characteristics of polymer coating material nearby the glassy state transformation temperature were analyzed. A mathematical model of the polymer viscoelasticity was built to describe the rheological behavior of polymer coating.Also, a method of numerical simulation was used to investigate the influence of controlling parameters on the hot rolled surface quality in the hot rolling process,and the rolling tests at the rolling speed of0.5,1.0 and 1.5 rad/s were performed.The results showed that at a constant temperature,the flow deformation of the polymer material increases with increase in time, and the stress relaxation phenomenon of coating pit morphology stops with decreases in temperature at the ending instant;with a constant rolling speed,the replication ratio of polymer coating pits increases with increase in temperature;the creep speed rises when the temperature is higher;specially,when the rolling temperature keeps 150 ℃ at 2T/3,the effect of morphology of polymer coating pit is the best,and prolonging the keeping pressure time can achieve the same filling effect at lower rolling temperature;the pit morphology after rolling is closest to the ideal one at the rolling speed of 0.5 rad/s to reveal the better time dependence of polymer.