Meaning
Mechanical displacement experienced by a material when subjected to both mechanical load and elevated thermal conditions. High-temperature strain measures the deformation of components in environments such as gas turbines or exhaust systems. This metric accounts for the combined effects of thermal expansion and time-dependent creep.
Material Fatigue
Elevated temperatures reduce the yield strength of most alloys and increase the rate of atomic diffusion. Under high-temperature strain, the accumulation of microscopic damage leads to the eventual formation of cracks. This process is the primary life-limiting factor for hot-section components.
Measurement Method
Specialized sensors like capacitance strain gauges or non-contact optical systems are required to capture data in these harsh conditions. Tracking high-temperature strain requires a precise understanding of the thermal expansion coefficient of both the sensor and the substrate. These measurements provide the data needed to validate structural models.
Maintenance Agreement
Long-term service contracts for industrial machinery use strain data to determine the interval between overhauls. If the recorded high-temperature strain exceeds the predicted envelope, the maintenance schedule is accelerated to prevent catastrophic failure. The contract defines the financial penalties for unplanned downtime caused by material degradation.
These clauses shift the risk of component wear to the service provider or the component manufacturer. Reliable monitoring reduces the overall cost of ownership for the plant operator.
