Fatigue performance testing device and method for bolt bearing large load at low temperature

Abstract

The invention relates to a fatigue performance testing device for a bolt bearing large load at a low temperature. The fatigue performance testing device comprises a cryogenic tank (1), guide columns (2), rotation shaft apparatuses (3), an upper loading pull rod (4), a test fixture (5), a cryogenic tank door (8), a liquid nitrogen inlet (9), a limit locking apparatus (10), a beam lifting apparatus (11), a loading apparatus (12), beams (13), a control panel (14), a displacement sensor (15), a nitrogen outlet (16), a base (17) and a lower loading pull rod (18). The fatigue performance testing device realizes test of the fatigue performance of bolt bearing the large load at the low temperature, can carry out low temperature dynamic low-cycle fatigue and programmed fatigue tests, and realizes fatigue performance parameter measurement and deformation behavior research when the bolt bears the large load at a condition close to a service environment. The fatigue performance testing device is simple in operations and has high practicability.

Description

technical field [0001] The invention relates to a device and method for testing the fatigue performance of bolts in a low-temperature environment and under large loads. The closed liquid nitrogen refrigeration is used, and the maximum dynamic load can reach 1500kN. Low-temperature dynamic low-cycle fatigue and program-controlled fatigue tests can be performed to realize low-temperature bolts. The characterization of dynamic and static mechanical properties, especially the low-temperature fatigue mechanical performance test of structures, belongs to the technical field of low-temperature mechanical testing. Background technique [0002] Cryogenic technology is an indispensable technology for many fields such as national defense construction, national economy and scientific research. With the rapid development of information, energy, machinery, aerospace and life sciences and other projects, as their related supporting technologies, cryogenic technology has also been obtained. ...

AI Technical Summary

Problems solved by technology

However, there are inevitably initial defects in bolted joints, which are prone to fatigue cracks under dynamic loads, especially in low temperature environments, where the bolt material is prone to low temperature cold and brittle, and the fatigue performance is even worse

In addition, although theoretical studies have shown that the fatigue strength measured at room temperature is generally safe for the design of low-temperature parts, bolted connections are prone to stress concentration problems, resulting in fatigue notches, and the sensitivity of materials to fatigue notches in low-temperature environments will improve

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