DAS Phase Strain
Convert DAS phase change into strain using supplied optical gauge parameters.
Description
DAS optical gauge conversion relates phase change to strain through refractive index, gauge length and a supplied strain-optic factor.
DAS optical gauge conversion relates phase change to strain through refractive index, gauge length and a supplied strain-optic factor. Phase sign is retained.1
Convert DAS phase change into strain using supplied optical gauge parameters.
When to use DAS Phase Strain
Use this tool to convert DAS phase change into strain using supplied optical gauge parameters.
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 DAS Phase Strain 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 phaseChangeRadians, wavelengthMeters, refractiveIndex, gaugeLengthMeters, strainOpticFactor using the field table and calculation rules, then run the tool.
- Read strain, microstrain. 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 |
|---|---|---|---|
| phaseChangeRadians | Optical phase change (rad) | number | Required |
| wavelengthMeters | Wavelength (m) | number; minimum: 0 | Required |
| refractiveIndex | Fiber refractive index | number; minimum: 0 | Required |
| gaugeLengthMeters | Gauge length (m) | number; minimum: 0 | Required |
| strainOpticFactor | Effective strain-optic factor | number; minimum: 0 | Required |
Enter finite signed phase, nonnegative wavelength and positive index, gauge length and factor. Return strain and µstrain.
strain=phase×λ/(4πindex×gaugeLength×strainOpticFactor) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| strain | Longitudinal strain | number |
| microstrain | Longitudinal strain (µε) | number |
{
"input": {
"phaseChangeRadians": 12.566370614359172,
"wavelengthMeters": 0.000001,
"refractiveIndex": 1,
"gaugeLengthMeters": 1,
"strainOpticFactor": 1
},
"output": {
"strain": 0.000001,
"microstrain": 1
}
}Limitations and assumptions
No phase unwrapping, transfer function, temperature separation or calibration fit 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 Interferometer Displacement: Convert reflected-path fringe count to displacement with refractive-index and angle correction. For a complementary task, use Doppler OCT Velocity: Convert Doppler-OCT phase change into axial and angle-corrected flow velocity.
References
-
DAS Phase Strain — tool.io
Similar or alternative tools
- Interferometer Displacement
Convert reflected-path fringe count to displacement with refractive-index and angle correction.
- Doppler OCT Velocity
Convert Doppler-OCT phase change into axial and angle-corrected flow velocity.