A Method for Measuring the Neutral Axis Position of Engineering Structures Using Modal Strains

Abstract

The invention discloses a method for measuring the position of a neutral axis of an engineering structure through modal strain. In a strain mode, the distribution of modal strain of the same cross section accords with a plane cross-section assumption, so the method can calculate the position of the neutral axis through measuring the modal strain of two different positions on the cross section. The method comprises five steps: dynamic strain response collection, strain modal analysis, modal strain extraction, neutral axis position coefficient extraction, and neutral axis height calculation. The method is clear in concept, is simple in flow, is suitable for traffic loading, environment excitation and artificial excitation, achieves the high-precision measurement of the position of the neutral axis of the engineering structure under the a non-static force, is high in market competiveness, and provides technological support for guaranteeing safe and effective operation of the engineering structure.

Description

technical field [0001] The invention belongs to the technical field of engineering monitoring and sensing, and in particular relates to a method for measuring the neutral axis position of an engineering structure by using modal strain. Background technique [0002] The neutral axis is an inherent characteristic of the structure and has nothing to do with external loads, and it is also an indispensable parameter for calculating and analyzing the bending performance of structures. When the structure is in pure bending, the neutral axis is at the point where the strain is zero. The measurement of the neutral axis generally uses a strain sensor to directly measure the strain, or uses a displacement meter to measure the displacement and convert it into a strain, and then use the distribution of the strain on the section to calculate the position of the neutral axis. However, there are the following typical problems in practice: (1) There are few pure bending conditions, usually ...

AI Technical Summary

Problems solved by technology

However, there are the following typical problems in practice: (1) There are few pure bending conditions, usually a combination of several stress states of bending, shearing and torsion. (2) The strain of engineering structures, especially concrete structures, under the action of external loads is very small, and the measured strain has high noise content, and the accuracy of direct analysis of the neutral axis position using strain is limited

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