Concrete stress sensor by piezoelectric properties of PVDF (polyvinylidene fluoride) film

Abstract

The invention discloses a concrete stress sensor by piezoelectric properties of a PVDF (polyvinylidene fluoride) film. The concrete stress sensor comprises an upper sensor shell, a lower sensor shell and the PVDF piezoelectric film, the upper sensor shell and the lower sensor shell are buckled together, the PVDF piezoelectric film is arranged between the upper sensor shell and the lower sensor shell, a nylon sleeve is sleeved on the periphery of the PVDF piezoelectric film, so that the PVDF piezoelectric film is positioned on a boss, insulating layers are respectively arranged on the upper end face and the lower end face of the PVDF piezoelectric film and closely contact with the upper sensor shell and the lower sensor shell, the nylon sleeve and the insulating layers form a sealed insulating space, so that a PVDF piezoelectric film and the sensor shells are separated in an insulating manner, and connection electrodes are respectively arranged on the upper surface and the lower surface of the PVDF piezoelectric film, so that piezoelectric signals are led to the outside of the sensor. The PVDF piezoelectric film is clamped between the two metal shells, a load is transmitted to the PVDF film by the aid of the sensor metal shells, the concrete stress sensor is sensitive in sensing, simple in structure, convenient to package and small in size, and can be embedded into concrete materials to finish an impact stress test.

Description

technical field [0001] The present invention relates to a stress sensor, which is used for measuring the stress of concrete material under impact load, in particular to a concrete stress sensor using organic piezoelectric material, especially a piezoelectric sensor using PVDF (polyvinylidene fluoride) film A characteristic concrete stress sensor belongs to the technical field of stress measurement. Background technique [0002] At present, sensors used in the field of shock testing are mainly divided into two types: piezoresistive and piezoelectric. [0003] So far, people have found a variety of materials that can be used as piezoresistive sensors, such as manganin, carbon, calcium, lithium, indium, lead, cadmium, bismuth and ytterbium, etc., among which the most common piezoresistive stress sensor is manganese Copper piezoresistive meter, although the piezoresistive coefficient of manganese-copper alloy, that is, the sensitivity is not very high, but because of its small ...

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Problems solved by technology

[0009] The technical problem to be solved by the present invention is to provide a piezoelectric stress sensor for measuring the stress distribution inside the material when the concrete material is subjected to impact load, so as to solve the problem that the existing sensors cannot effectively capture the stress of the concrete material. When subjected to impact load, the problem of stress time history at the measuring point inside the material

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