DOI: 10.14489/td.2015.12.pp.060-068

Klyuev V.V., Bobrenko V.M., Bobrov V.T.
ACOUSTIC TENSOMETRY OF DETACHABLE JOINTS. STATE AND PROSPECTS. Part 1
(pp. 60-68)

Abstract. Split compounds are widely used in important structures and installations operating under high pressure, at loads approaching the yield strength of threaded metal parts in a vacuum space, wide temperature fluctuations, vibrations and other impacts. A review of accidents and disasters associated with detachable joints failures, leading to the depressurization of spacecrafts, gas pipelines and other objects, has shown that this leads to leakage of gas, oil, hazardous chemicals, explosions, fires, loss of life and destruction of infrastructure. The cause of abnormal situations is imperfect assembly, quality control and tightening torques of threaded connections, low measurement accuracy and uniformity of the tightening efforts of individual elements of detachable joints. Analysis of the results of the study of physics processes, methodologies and technologies of the acoustic strain measurement on the example of the threaded connections of the power equipment allows us to recommend this method for widespread use. It is noted that a large-scale use of acoustic methods of efforts tightening control, along with the improvement of the design and manufacturing technology has significantly increased the reliability of the liquid rocket engines while considerably reducing the cost of testing of the design as a whole, to enter the international market of space technology. The State Standard GOST R 52889–2007 “Non-destructive testing. The acoustic method of control efforts tightening threaded connections. General requirements” developed and put into effect is the first normative document regulating the use of the method of detachable joints acoustic strain measurement. The method regulated by the standard can be used in the assembly during manufacture, installation, commissioning and maintenance works during the operation of critical structures in industry and other spheres. It is given the examples of effective use of the method as in Russian engineering and launching of American satellites as parts of American rockets. There is little attention to this method from local organizations operating critical structures with detachable joints. The authors see further development of the method, equipment and technology of acoustic strain measurement in expanding the use of information technologies, intellectualization of control process and application of ultrasonic testing of excitation without requiring the use of liquid contact.

Keywords: accident, acoustic strain measurement, acoustic diagnostics, acoustic elasticity, bearing capacity, detachable connection, threaded parts, depressurization, leakage, liquid rocket engines, hydroelectric power stations, rail fasteners, torque bolts and studs, intellectualization, the loss of personnel, material losses.

 

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