VW & Arc-Weldable Type Strain Gauge
SJ-4000

│ DESCRIPTION │
VW Load Cell is to measure the reaction force available at Earth Anchor to analyze in connection with the change of the retaining wall and judgment of the stability of the support after construction of anchor. Also, it is to measure the axial force affecting the strut.

│ APPLICATION │

• To measure axial force of the strut for shielding or timbering.
• To measure strain for shielding steel materials of bridge and building which is under construction or finished construction
• To measure the strain for supports and tunnel lining
• To measure the stress concentration of pipe line
• To measure the concrete strain using anchor for concrete surface mounting.

│ FEATURE │

• Excellent reproducibility and responsiveness which is free from cable length or resistance change
• Perfect waterproof structure
• High stability and high sensibility
• High accurate resistance temp sensor mounted.

│ CHARACTERISTIC │

The body of VW Arc-Weldable Strain Gauge is composed of the sensor processed by airtight epoxy, stainless steel tube and the mounting block welding on both edge. Magnetic coil is mounted in the sensor inside. Vibration wire with proper tensile force on both edges is mounted in the body of the stainless steel tube.

The displacement of two mounting blocks for welding both edges causes different tensile force in vibration wire to change the magnetic field, so this will generate the resonant frequency to the electron beam. This resonant frequency is transmitted to the output device to display the engineering unit and it can be calculated as the stress and strain easily and accurately by the conversion coefficient provided. The vibration sensor has the excellent responsiveness and reproducibility and it is almost not affected by the secular change, so it is most suitable for permanent measurement.

The vibration sensor measurement outputs vibration counts instead of voltage and one of the greatest advantages is that it is almost not affected by the resistance change of electronic cable, electric leakage, noisy and contact resistance with the ground. High accurate resistance temp sensor is mounted to compensate the thermal expansion factor of the gauge due to the change of temp.

│ SPECIFICATION │

※ The product spec is subject to change without prior notice in order to enhance the product’s quality.

│ REFERENCE │

• Strain (με) calculation:
  - Microstrain (με) = Gage Factor × 10-3 × F2 = Gage Factor × 109 / N2
  Whereas, F=Hz measurement value, N=microsec measurement value, Gage Factor=4.062
• Stress (σ) calculation:
  - stress (σ : kg. cm²) = -1.0 × Strain (ε) × Material elastic modulus €
• Axial force (P) calculation:
  - Axial Force (P : ton) = Stress (σ) × Material cross section (A) ÷ 1000
• Standard installation : Steel pipe and Strut