Double-grids strain gauges
The main feature of double-grids strain gauges is that there are two sensitive grids, and the two grids are 90° or 0° axially to each other. In general, the use of these strain gauges must be known in advance of their stress or strain direction. The main structural forms are "BB", "HA", "GB" and "FB". The two grids of BB strain gauge are perpendicular to each other, that is, the "T" type strain gauge, which is mainly used to test axial strain and transverse strain (also known as Poisson strain); The two grids of the HA strain gauge are 90° perpendicular to each other and 45° in the horizontal direction, that is, the "V" type strain gauge, which is mainly used to measure physical quantities such as shear stress and torque; The two grids of the GB strain gauge are in the same axial direction, which is mainly used to measure materials or structures in the same axial direction with different forces. FB strain gauge two grid parallel to each other, mainly used to measure side by side different gradient stress or strain.
PRODUCT MODEL TABLE (Unit: mm)
| MODEL |
GRID DIM |
BACKING DIM |
CREEP |
|
| L (mm) |
W (mm) |
L (mm) |
W (mm) |
| BF350-3BB-A |
3.0 |
3.0 |
6.8 |
7.6 |
|
| ZF1000-3BB-A |
3.0 |
3.0 |
6.8 |
7.6 |
TECH SUPPORT
Types to select We should select strain gauge according to the tested purpose, the materials and precision demands of the tested goods. For example, the sense organ of the load cell, then it need to select the Foil strain gauge which is small P and θ; If the sensitivity of the load cell needs to be large, then we should select Semiconductor strain gauge; we should select Foil strain gauge if we test the dynamic weighing.
The fundus materials of the Sensitive Grids How to select the best and suitable Sensitive Grids or fundus materials? First, we should according to the environment, temperature, tested time and the ultimate straining, then we also need to consider the precision demand of the strain gauge, For example: In -30~+80 , you should choose ºC CuNi, NiCrFe or Phenolic strain gauge; And in 80~150 , the ºC n use Polyimide strain gauge is better. The resistance of strain gauge We consider and select the resistance of strain gauge according to the demands which the test equipment require to the resistance and sensitivity of strain gauge etc. For example, in the stress test, we usually use 120ohm train gauge to match the equipment; To the load cell, we use high resistance (350ohm, 500ohm, 1000 ohm even larger etc.) to improve its stability and sensitivity, sometimes we also consider the performance and the values and the function, we use high resistance strain gauge.
Dimension of strain gauge We decide the dimension of strain gauge according to the materials, stress and the sticked area.
For example, we use longer grids strain gauge if the stress is proportional or the changing is small, and it allow to stick on a large area, in this condition, we suggest to use 3~6mm's grids; but we use the grids length≤1mm, if the stress is collected in area or the sticked area is small. The long grids strain gauge is good for stick, connection and good cool function; it also can improve the performance of the strain gauge. The dimension of the strain gauge is smaller, the demands of strict quality are higher, and the cool function is weaker, so on conditions of insure the precision and have enough sticked area, it is better to use long grids strain gauge.
The configuration of the Sensitive Grids We select the configuration of the Sensitive Grids according to the stress and other demands. Like when the main stress is unknown or shear strain, then we can select multi-axes strain gauge, we use these strain gauge which Triaxial angle are 45°, 60° or 120° for the first situation; And use Triaxial angle is 45° for another situation. If we test the know stress strain, then we can select Uniaxial strain gauge; the circle multi-axes strain gauge is used in Pressure sensor.
Temp. Self-compensation and Elastic Modulus self-compensation We should select different Temp. Self-compensation or Elastic Modulus self-compensation strain gauge according to its materials, working Temp. and the precision. Like some common steel or spring steel, then use Temp. Self-compensation strain gauge with the 11×10/ expansion coefficient; And to ºC the Aluminum alloy, then use strain gauge with 23×10/ expansion coefficient. ºC
Creep Grade The user should select the matching Creep Grade according to the configuration, capacity and Elastomer of the load cell. First time we can select one or two kind of different Creep Grade's strain gauge to test, and according to the last test data, and then select the best Creep Grade.
The main feature of uniaxial strain gauge is that it has a single sensitive grid( Single sensitive grid strain gauge is quarter bridge strain gauge), which is used to measure the strain in the axis direction of the sensitive grid.
The structure form of the sensitive grid includes the shape, number and direction of the sensitive grid, the size of the
transverse grid, the shape and distribution of the welding end, and the transverse width of the sensitive grid, which can bedivided into uniaxial strain gauge, multi-axial strain gauge and compound strain gauge.
The main feature of uniaxial strain gauge is that it has a single sensitive grid( Single sensitive grid strain gauge is quarter bridge strain gauge), which is used to measure the strain in the axis direction of the sensitive grid. There are two types of structure: "AA" and "AB". The sensitive grid of "AA" is a uniaxial horizontal structure, which can measure tensile, compressive,bending strain and displacement. "AB" is a uniaxial 45° sensitive grid structure, which can measure bending distance, torque,shear strain, etc.
We select the configuration of the Sensitive Grids according to the stress and other demands. Like when the main stress is unknown or shear strain, then we can select multi-axes strain gauge, we use these strain gauge which Triaxial angle are 45°, 60° or 120° for the first situation; And use Triaxial angle is 45° for another situation. If we test the know stress strain, then we can select Uniaxial strain gauge.
Audited Supplier 
Types to select We should select strain gauge according to the tested purpose, the materials and precision demands of the tested goods. For example, the sense organ of the load cell, then it need to select the Foil strain gauge which is small P and θ; If the sensitivity of the load cell needs to be large, then we should select Semiconductor strain gauge; we should select Foil strain gauge if we test the dynamic weighing.
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