In order to solve the problem of loosening and stripping of double-end studs on the intermediate casing of an aero-engine

the comprehensive failure analysis and troubleshooting were carried out from the aspects of installation strength

applied load and manufacturing defects. The main reason is that the decomposition torque of the self-locking nut is greater than the assembly torque of studs. Secondly

the high temperature of the cavity and the vibration of the engine will further aggravate the fatigue failure of the studs. And the assembly process of double-end studs based on the combination of temperature difference and vibration was proposed

where the stud was firstly heated

and then axial highfrequency vibration was added to the stud during the tightening process. Comparison tests and application experiments were performed. Results show that the average stripping failure rate of the double-end stud decreases from 21.6% to 3.2%

that is

the proposed assembly process can effectively improve the assembly quality of double-end studs

and increase the installation strength and stability of studs without damaging the quality of the thread teeth. The stripping failure of double-end studs is avoided effectively and the safety and reliability of aero-engine during test and flight are guaranteed.