Finite element analysis of crosshead mechanical performance in ultra-high pressure drilling pump for ultra-deep wells

Abstract:

To address the urgent demand for an 80 MPa ultra-high-pressure drilling pump in 15000 m ultra-deep well drilling， and to overcome the bottleneck that existing digital twins lack mechanical data under extreme operating conditions， a systematic mechanical performance analysis was conducted on the crosshead， a key component of the ultra-high-pressure drilling pump. First， based on hydraulics theory， the rated pump pressures and displacements under different liner diameters （110~180 mm） were calculated， and a kinematic and force model of the crosshead was established to define its load boundary conditions. Subsequently， based on the Hertz contact theory， finite-element static simulations were performed using COMSOL software under various combinations of liner diameter and pump pressure. The results indicate that the maximum stress on the crosshead is positively correlated with both liner diameter and pump pressure， and the effect of liner diameter variation on stress is significantly greater than that of pump pressure. The stress concentration zone is located at the transition fillet between the outer edge of the pin hole and the lug body. Under the rated-pressure and maximum-displacement conditions， the maximum stresses are 133.3 MPa and 142.8 MPa， respectively， both far below the material''s yield strength of 860 MPa. This study quantifies the stress-response surface under coupled liner-diameter-pump-pressure operating conditions， fills the gap in mechanical data for the power end of ultra-high-pressure pumps for ultra-deep wells under extreme conditions， and provides a theoretical basis for on-site cylinder liner replacement strategies and fatigue-life prediction of crossheads.