Meaning
Change in the electrical resistance of a bonded sensor caused by thermal expansion rather than physical loading. Strain gages applied to metal surfaces produce apparent strain as the ambient temperature shifts and the substrate expands.
Temperature Compensation
Mathematical correction factors permit the isolation of mechanical forces from environmental noise. Sensors matched to the expansion coefficient of the material help minimize the initial magnitude of apparent strain during operation. Software algorithms apply secondary corrections based on a local temperature probe.
Accuracy remains dependent on the stability of the bridge circuit.
Data Accuracy
Integrity of the reported stress levels depends on the effective removal of non mechanical variables. High levels of apparent strain mask the actual load being applied to a structure. Operators rely on zero shift data to determine if a measurement system requires recalibration.
Consistent readings are required for long term structural monitoring. Reliability of the final report is contingent on the proper subtraction of these thermal effects.
Contractual Performance
Acceptance criteria for heavy machinery testing specify the maximum allowable error margin for instrumentation. Excessive apparent strain that remains uncorrected can lead to the rejection of a production batch. Liability for faulty data falls on the testing facility if standard procedures are ignored.
Clear definitions of measurement uncertainty protect the manufacturer.
