BOTDA Strain and Temperature

Separate strain and temperature change from two calibrated distributed-sensing shifts.

Description

Two calibrated sensing channels can separate strain and temperature when their sensitivity vectors are independent.

Two calibrated sensing channels can separate strain and temperature when their sensitivity vectors are independent. The tool solves that supplied linear system.^[1]

Separate strain and temperature change from two calibrated distributed-sensing shifts.

When to use BOTDA Strain and Temperature

Use this tool to separate strain and temperature change from two calibrated distributed-sensing shifts.

Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.

How to use BOTDA Strain and Temperature and understand its results

Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
Enter firstShift, secondShift, firstStrainCoefficient, firstTemperatureCoefficient, secondStrainCoefficient, secondTemperatureCoefficient using the field table and calculation rules, then run the tool.
Read strain, temperatureChange. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
firstShift	First measured shift	number	Required
secondShift	Second measured shift	number	Required
firstStrainCoefficient	First strain coefficient	number	Required
firstTemperatureCoefficient	First temperature coefficient	number	Required
secondStrainCoefficient	Second strain coefficient	number	Required
secondTemperatureCoefficient	Second temperature coefficient	number	Required

Enter finite signed shifts and four coefficients on consistent units. Reject exactly zero determinant; solve the 2×2 system and return signed strain and temperature change.

[strain,temperatureChange]=A⁻¹[firstShift,secondShift]

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
strain	Solved strain	number
temperatureChange	Solved temperature change	number

json

{
  "input": {
    "firstShift": 5,
    "secondShift": 4,
    "firstStrainCoefficient": 1,
    "firstTemperatureCoefficient": 2,
    "secondStrainCoefficient": 2,
    "secondTemperatureCoefficient": 1
  },
  "output": {
    "strain": 1,
    "temperatureChange": 2
  }
}

Limitations and assumptions

No coefficient calibration, noise propagation or near-singular conditioning test is performed.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Air-Biased THz Field: Subtract unbiased background and normalize an air-biased coherent THz field measurement. For a complementary task, use DAS Phase Strain: Convert DAS phase change into strain using supplied optical gauge parameters.

References

BOTDA Strain and Temperature — tool.io

Similar or alternative tools

Air-Biased THz Field
Subtract unbiased background and normalize an air-biased coherent THz field measurement.
DAS Phase Strain
Convert DAS phase change into strain using supplied optical gauge parameters.