A dynamic model for multispan rotating gundrill shaft with thrust force and coolant pressure is proposed using rotational Euler–Bernoulli beam model (REB) through energy approach. From the numerical simulation, it is found that the 1st critical RPM of the rotating gundrill shaft increases tremendously as coolant pressure increases. The proposed model is incorporated with a straightness model. Experimental verification for the proposed model is presented. It is found that by using the combination of higher pressure (2000 psi) and rotational speed (1600 rpm), a straighter hole within industrial tolerance is achieved in gundrilling of Inconel-718.

中文翻译：

---

含冷却液的多跨喷枪井动态行为建模及其对直线度的影响

通过能量方法，利用旋转欧拉-伯努利梁模型（REB），提出了具有推力和冷却剂压力的多跨旋转钻杆轴动力学模型。从数值模拟中发现，随着冷却液压力的增加，旋转枪钻轴的第一临界RPM急剧增加。提出的模型与直线度模型合并在一起。提出的模型的实验验证。发现通过结合使用较高的压力（2000 psi）和转速（1600 rpm），可以在Inconel-718的喷孔加工中在工业公差范围内形成一个直孔。