Multiple-spindle ratchet wheel strain testing system and method of pipe bend

Abstract

The invention relates to a multiple-spindle ratchet wheel strain testing system and method of a pipe bend. The applied load F and output pressure P of a hydraulic servo fatigue testing machine are jointly controlled by a microcomputer and a sensor so as to provide various complex load working conditions, and a real-time multiple-spindle ratchet wheel action of the bend under the complex load working conditions is measured by a stain gauge method; and the variation situation of strain applied to the bend is measured by utilizing the sensor to control the hydraulic servo fatigue testing machine, a clamping fixture auxiliary mechanism and the strain gauge method, data is collected by a multi-channel dynamic strain instrument, and the result is output through the computer. According to the invention, multiple complex load combination working conditions can be provided, the load working conditions and the application range are wide, the measurement position can be adjusted flexibly, namelythe strain gauge sticking position can be selected freely according to concrete test designs, and is not restricted by the test conditions; the test result has high accuracy, the data curve is smoothad stable, and the design is reasonable; and the multi-channel dynamic strain instrument has the characteristics of low drift, low noise and wide frequency response.

Description

technical field [0001] The invention relates to a method for testing the strain evolution of a ratchet wheel at each position of a pipe elbow under the action of a multi-axis cyclic load, which belongs to a bend pipe multi-axis ratchet strain test system and method. Background technique [0002] At present, in testing the ratchet strain evolution of pipe elbow materials under multi-axial cyclic loads at home and abroad, the multi-axial ratchet strain tests are mostly performed on standard specimens of elbow material bars or plates, mainly using the extensometer method wait. However, there are many problems with this method. First, it only considers the ratchet behavior of the material itself under load, and cannot be effectively used to study the influence of the structure on the multi-axis ratchet effect. In addition, its loading conditions and types are limited, and The positioning, fixing and calibration of the extensometer are complicated, and improper operation can eas...

AI Technical Summary

Problems solved by technology

Although it can conduct direct loading research on the elbow structure, this method provides a small load range and a single loading type, which is limited by itself.

In recent years, although some scholars have also proposed the strain gauge method to test the multi-axis ratchet effect of elbows, due to the limitations of insufficient data acquisition accuracy, limited test channels and inaccurate test position positioning, the test procedures are complicated and the results are inaccurate.

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