Research On Self-loosening Problem Of Combined Rotor Rod-bolt Under Load Fluctuation

As the core of modern gas turbine components, performance degradation studies rotor rod combinations for the protection of the safe and reliable operation of the machine is essential. Rod combination rotor made of a combination of rod bolt preload, therefore, the combination of rotor performance degradation and reliability connecting rod bolts are closely related. Since self-loosening is one of the main rod bolts affect the reliability of the connection, and cyclic lateral loads are key factors from the relaxation of the problem. Therefore, this paper since the self-loosening problem rod bolts cyclic lateral loads, conduct relevant research, as follows:Firstly, According to the actual load fluctuation occurs in the gas turbine operation, the load variation of the composition analysis of the rotor rod bolts. Discovered by the lateral load rod bolts will also appear in alternating operation, especially in the lateral load will speed changes suffered mutations. Subsequently, the analysis of the effects of alternating lateral loads on the mechanical behavior of rod bolts, alternating lateral loads to determine the key factors rod bolt from the self-loosening.Secondly, ANSYS software to build parametric threaded rod bolts dimensional finite element model for rod bolt preload pure simulation based on this model to get the thread load distribution and contact stress distribution, verify the rationality of the model. And found fragile parts of the rod bolts running performance degradation in service for the first thread of the bolt and nut bearing surface.Thirdly, In alternating lateral loads, rod bolts model, combined with a variety of different operating conditions, analysis of changes in preload rod bolts, nuts loosen unwinding, meshing contact stress and micro-slip condition between cumulative thread, Comprehensive analysis of the self-relaxation problem alternating transverse load rod bolts. And analyze the relation between the lateral displacement fretting transverse shear force and get a visual description of rod bolts from slack laws.Finally, Experimental study of alternating lateral bolting preload changes under load and unscrew the nut accumulation resulting finite element analysis to verify the correctness of the lawThe above conclusions on the one hand the development of a modeling portfolio rotor rod bolts; On the other hand has some value to optimize the design of Combination Rotor construction, reliability analysis, and performance degradation monitoring.