An experimental method and device for bending stiffness of overhead cables under tension-bending combination

Abstract

The invention belongs to the field of overhead cable testing, and relates to an experimental method and device for bending stiffness of an overhead cable under tension-bending combination. The traditional three-point bending test cannot measure the response of overhead cables under combined tension and bending loads. This proposal provides a measurement device and experimental method for the bending stiffness of overhead cables. According to the actual working conditions, the load equivalent method is adopted. By improving the three-point bending test, design a set of experimental support consisting of base support, extension frame and vertical support frame, and use a universal testing machine to apply radial tension, and hang weights at both ends of the sample cable to exert force on the sample cable. Axial tensile force, the tensile force output from the universal testing machine and the displacement data of the middle point of the cable body, combined with the data of two laser sensors symmetrical to the middle point, the bending of the overhead cable under the combination of multiple reciprocating stretching and bending is calculated and analyzed. The hysteresis curve of moment and curvature can be used to study the change of bending stiffness.

Description

technical field [0001] The invention belongs to the field of overhead cable testing, and relates to a bending stiffness experiment method and device under the combination of tension and bending of an overhead cable. Background technique [0002] As an important equipment for power transmission, overhead cables play a role in power transmission. As the distance between the two electrical towers gets farther and farther, the overhead cable is suspended in the air and is more and more affected by the alternating load of tension and bending under the action of wind. The overhead cable is prone to fatigue failure, so the dynamic cable is accurately predicted. fatigue life is extremely important. [0003] Due to the special structure of the overhead cable, the internal functional unit is made of multi-layer wires twisted at a certain helical angle. When the wire layer is subjected to a large bending moment, the wires between the layers will slide, and under the action of tension,...

AI Technical Summary

Problems solved by technology

However, the existing three-point bending test equipment can only measure the stiffness change of a single bending, but cannot perform multiple bendings, and cannot apply tension to the sample cable

The relevant experimental equipment is developed for large-diameter flexible pipe cable bending equipment. When it is used in the bending test of overhead cables, the problem of insufficient accuracy will occur.

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