Load and loosening characteristics of distributed tension rod bolt thread in gas turbine rotor
As to the uneven load distribution and loosening characteristics of distributed tension rod bolts for gas turbine rotors,the thread load distributions of the tension rod bolts in four forms are studied,which are the metric thread,the internal cone thread,the metric thread with unloading groove,and the internal cone thread with unloading groove.The load distribution characteristics of each thread tooth is analyzed.The results indicate that the load distribution of the internal cone thread with unloading groove is the most uniform.Regarding the load characteristics of gas turbine rotors during operation,the loosening processes of the tension rod nuts under various load factors are simulated using finite element quasi-static method,and the preload force variation and the maximum slips of the first thread under different loads are studied.The results show that:the bending moment of the rotor will not cause the nut loosen,and the accumulation of multiple short circuit torques leads to a significant reduction in the pre-load force,and then under the continuous action of lateral loads,the pre-load force slowly decreases,and the tension rod nut becomes loose;under three different loads,the reduction in pre-load force of the internal cone thread with unloading groove is the smallest.
tension rod boltload distributionlooseningpre-loadfinite element
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