Effects of nano diamond particles on contact fatigue life of steel ball were evaluated on a self-made ball-rodcontact fatigue tester.
利用自制的球-棒疲劳试验机，研究了纳米金刚石粉对钢球接触疲劳寿命的影响。
2
End face with a gap, no boss butt is refers to the upper and lower casing left a certain gap between the upper and lower main chord rod end face at the same time contact.
端面有间隙、无凸台对接是指在上、下套管之间留有一定间隙，上、下主弦杆端面同时接触对接。
3
The dynamic strength of rod string and the mount position of centralizer were calculated, according to the acquired deformation of rod string and its impact contact force with tube in the time domain.