关键词: 水电机组, 主轴螺栓, 预紧力控制, 弹性相互作用, 同步拉伸

Abstract: As a key part of power transmission,the reliability of bolt connection of hydroelectric unit spindle system is directly related to the safety and stability of unit operation. For the engineering problem of uneven distribution of residual preload force due to elastic coupling in multi-bolt structure,a mathematical model of bolt residual preload force based on the theory of elastic interaction was established,and a common node finite element model with a certain type of hydroelectric unit spindle connection structure was built,three groups of synchronized step-by-step loading strategy and a single group of continuous loading strategy were proposed,and a comparative simulation analysis was carried out to reveal the influence mechanism of the loading path on the distribution of residual preload force. On the basis of the preferred loading scheme,the two-step loading strategy with different tightening ratios was further proposed to systematically analyze the control effect of the first loading ratio on the consistency of the bolt residual preload force. The simulation results were validated through an assembly test, and the results demonstrated the applicability of the established finite element model and multi-step loading strategy in the optimization of the bolt pre-tightening process, as well as the feasibility of the two-step different tightening ratio strategy in the consistency of pre-tightening force and the quality of the assembly. The research results can provide theoretical basis and engineering support for the optimization of assembly process of large bolted structures.

Key words: hydroelectric units, spindle bolts, preload control, elastic interaction, synchronized stretching