Life prediction method for fatigue crack growth of high-lock bolted joints based on stress monitoring

Abstract

This application belongs to the field of machinery, and in particular relates to a stress monitoring-based fatigue crack growth life prediction method for high-lock bolt connectors. The fatigue testing machine is set up through the fatigue test control system to apply a constant amplitude load to the standard test piece of high-lock bolts. Foil strain gauges are pasted on the edge of the hole of the standard test piece, and the stress change of the hole edge of the single-detail standard test piece is monitored in real time by the stress monitoring system. The test signal collected by the NI data collector is sent to the computer for real-time processing through the stress monitoring system, and the whole In the process of stress changing with time in the fatigue test, according to the law of stress changing with time at the hole edge of the single-detailed standard test piece, the crack growth life when the crack grows to 0.8mm is obtained by inferring the fitting curve. The application system has simple structure and convenient operation. Since it does not require a large amount of fracture analysis work, it does not have high requirements for sensors and acquisition equipment, thereby reducing labor costs and the cost of required test equipment.

Description

technical field [0001] The present application belongs to the mechanical field, and in particular relates to a stress monitoring-based fatigue crack growth life prediction method for high-lock bolt connections. Background technique [0002] In engineering practice, structural connectors are usually strengthened. For the unstrengthened single-detailed through-hole test piece, the marking load is usually added to the constant-amplitude load. After the test is completed, the crack extension life of a certain size is reversed by observing the stripes formed on the fracture surface. [0003] The above-mentioned method can observe the stripes in the fatigue test of the through-hole test piece, but it is actually found that no clear stripes are observed in the fatigue test of the strengthened high-lock bolt test piece, which is used to inversely calculate the crack formation life. Moreover, fracture analysis is an experience-based technique in structural fatigue testing, and it is...

AI Technical Summary

Problems solved by technology

The above-mentioned patents only predict the fatigue life through the S-N curve and the linear fatigue accumulation method, which has limitations and cannot fully and accurately predict the fatigue life of the parts

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