Strain-Gauge Data Processing Workflow
How to process strain-gauge test data for FEA correlation — units, scaling, filtering, gauge orientation and uncertainty.
Engineering Task
Processing raw strain-gauge data from a physical test for comparison with FEA predictions.
Workflow
- Convert raw voltage to microstrain using the gauge factor and bridge configuration
- Apply zero-balance correction — subtract the initial reading before loading
- Apply shunt calibration correction if the gauge was shunt-calibrated
- Filter the data — remove electrical noise (50/60 Hz) without removing signal
- Scale to the FE load level if the test was at a different load (verify linearity)
- Convert to stress if needed: σ = E × ε (for uniaxial) or use rosette equations
Key Considerations
- Verify units — microstrain (×10⁻⁶) is standard; do not mix with percent strain
- For rosette gauges: compute principal strains using the rosette equations, not individual arms
- Account for gauge factor tolerance (typically ±0.5%) and bridge nonlinearity for quarter-bridge
- Filtering: use a low-pass filter with a cutoff above the highest frequency of interest
- Record the gauge location, orientation and grid ID for traceability