The working principle of resistance strain gauge and the function of resistance strain gauge
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# The working principle of resistance strain gauge and the function of resistance strain gauge

Posted Date: 2024-02-03

The working principle of resistance strain gauge and the function of resistance strain gauge

Resistance strain gauge is a common strain measurement element that can be used to measure the strain change of an object. The principle of its working is based on the characteristics of resistive materials that produce changes in resistance value under the action of force or strain.

Resistance strain gauges are usually made of elastic metal materials, such as steel, copper, etc. When a resistance strain gauge is stressed or stretched, its shape and size change, causing the material's resistance value to change. This change is due to changes in the microstructure inside the strain gauge, in which the movement of electrons is affected.

Specifically, there are one or more fine conductive paths inside the resistance strain gauge, called a measurement grid. These tiny conductive paths stretch or compress under strain, causing changes in the geometry and resistance of the conductive paths. When the strain gauge is stretched, the conductive path will be stretched and lengthened, causing the resistance value to increase; and when the strain gauge is compressed, the conductive path will be compressed and shortened, causing the resistance value to decrease.

In order to measure the resistance change of a resistor piece, resistance strain gauges are usually assembled in a circuit. This circuit includes a power supply and a module for measuring resistance. By measuring the change in resistance of the resistor piece, we can calculate the amount of strain.

Resistance strain gauges are widely used in engineering fields. Its main function is to measure the strain changes of the object and then obtain information about the force or force changes of the object. Depending on the type of force that needs to be measured in the background, resistance strain gauges can be divided into two types: pressure type and shear type.

Pressure resistance strain gauges are mainly used to measure the tensile or compressive strain of objects, such as measuring the deformation of bridges and bearings. These strain changes will lead to changes in the resistance value of the strain gauge. By measuring the change in resistance value, the strain information of the object can be obtained, thereby deriving information about the force or force changes on the object.

Shear resistance strain gauges are mainly used to measure the shear strain of objects, such as measuring rotor speed, car chassis deformation, etc. The structure of the shear resistance strain gauge is relatively complex, usually including two parallel measurement grids and two mutually perpendicular excitation grids. When an object is subjected to shear stress, the deformation directions of the two parallel measurement grids are opposite, resulting in a change in the resistance value. By measuring the change in resistance value, the shear strain information of the object can be obtained, and then the shear stress or rotational speed information of the object can be derived.

In addition to the above applications, resistance strain gauges can also be used to measure temperature changes. In some temperature sensors, an insulating coating can be used to protect the resistance strain gauge, and a circuit is used to measure the resistance change and deduce the temperature change.

To sum up, the resistance strain gauge is a commonly used strain measurement element. It can obtain information such as the force, deformation, and temperature of an object by measuring changes in resistance value. It has simple working principle, compact structure and wide application range. In the engineering field, resistance strain gauges have a wide range of applications, such as bridge deformation monitoring, automobile chassis deformation monitoring, mechanical speed measurement, etc.

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