Fastener pretightening force online detection method and system

Abstract

The invention provides a method and system for the on-line detection of a pretightening force of a fastening device, and the method comprises the steps: carrying out the shock excitation of a detected workpiece system, wherein the detected workpiece system mainly consists of a fastening piece and a mechanism which is fastened by the fastening piece; carrying out the vibration pick-up of a real-time response signal of the detected workpiece system for the shock excitation; obtaining the real-time frequency spectrum response information of the detected workpiece system according to the real-time response signal; and recognizing an axial pretightening force of the fastening piece according to the real-time frequency spectrum response information. The method and system gives consideration to the rigidness change of the detected workpiece system before and after the fastening piece carries out pretightening, and the rigidness change enables the detected workpiece system to generate the change of frequency spectrum response under broadband excitation. Therefore, the method and system recognizes the axial pretightening force through the analysis of the frequency spectrum response and the change of multi-order mode modal response, thereby achieving the on-line detection.

Description

technical field [0001] The invention relates to the field of pretightening force detection, in particular to an online detection method and system for the pretightening force of fasteners. Background technique [0002] In the mechanical industry, fasteners (such as threaded bolts, preloaded springs and other workpieces) have been widely used. However, due to the fact that fasteners will be subjected to complex alternating load impacts during mechanical operation, it is very easy to induce fracture failure of fasteners or changes in rated preload due to deformation, which will seriously affect the overall system work. security and stability. [0003] After investigating the traditional fastener pre-tightening force detection scheme, it is found that the main methods for fastening workers' pre-tightening detection are empirical detection method, torque wrench method, sensor detection method and so on. Due to the subjective judgment of human beings, the empirical detection me...

AI Technical Summary

Problems solved by technology

Due to the subjective judgment of human beings, the empirical detection method has considerable randomness in the results, and it is difficult to identify small errors.

Although the torque wrench method is simple and easy to use, it is limited by the accuracy of the torque wrench itself, and it is difficult to realize the function of online detection

The sensor detection method has high accuracy, but some types of sensing need to pre-embed the sensing coil or gasket on the fastener, which damages the integrity and integrity of the workpiece, resulting in damage to the strength and rigidity of the workpiece, so that it cannot Meet the needs of stable work and synchronous real-time detection

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