Meaning
Output errors in strain sensors caused by the temperature-induced expansion of both the sensor material and the test specimen must be compensated for during structural testing. The presence of thermal apparent strain means that a sensor bonded to a heated component will register a change in strain even when no external mechanical load is applied. This thermal drift applies to all resistive and optical strain measurement devices operating under fluctuating temperatures.
Measurement Correction
Laboratory technicians must calculate the non-mechanical strain component to ensure the accuracy of structural tests. Utilizing specialized compensation curves allows engineers to subtract the thermal apparent strain from the raw sensor output. This correction reveals the true mechanical stress acting on the component during high-temperature cycles.
This process is essential during the testing of turbine blades and exhaust systems.
Product Pricing
High-performance sensor systems include built-in temperature compensation features that calculate and remove these errors automatically. Sensor networks with integrated thermal apparent strain correction command a premium list price compared to uncompensated alternatives. Distributors market these advanced systems to research and development laboratories that require high-precision data without the need for manual calculations.
The lower labor requirement justifies the higher landed cost.
Warranty Risk
Failure to correct for these temperature errors can lead to incorrect structural assessments and catastrophic product failures. When a testing lab fails to account for thermal apparent strain, it can approve a component that is actually under excessive stress, leading to early failure in the field. This error can result in massive warranty claims against both the lab and the component manufacturer.
