In Situ Thermal Aging Calibration Corrections for High Temperature MEMS Transducer Arrays
Dynamic matrix corrections combine in situ reference tracking and Arrhenius modeling to eliminate unbudgeted high temperature MEMS recalibration cycles.
Mechanical Stress Relaxation
Elastic Recovery
Gradual reduction of internal forces occurs within a material held at a constant strain over time. In pressure sensor housings and load cell bodies, mechanical stress relaxation causes a slow shift in the zero-point calibration.
Thermal Acceleration
Heat provides the energy required for atoms to rearrange themselves and relieve internal tension. Higher temperatures significantly increase the rate of mechanical stress relaxation, leading to rapid changes in the pre-load of bolted joints. This effect is a primary concern for sensors operating in engine compartments or industrial furnaces.
Specialized alloys are chosen for high-temperature applications specifically for their resistance to this type of creep.
Calibration Drift
Stability of a measurement system depends on the physical dimensions of the sensing element remaining constant. When mechanical stress relaxation alters the shape of a diaphragm or a spring, the output of the transducer no longer matches the original factory setting. Regular recalibration identifies these shifts, but the underlying physical change is usually permanent.
Installation Torque
Clamping forces applied during the mounting of a sensor can induce measurable internal stress. Over months of operation, mechanical stress relaxation in the mounting bolts or the sensor flange can lead to a loss of seal integrity. Proper installation procedures specify the use of hardened washers and specific torque sequences to distribute the load evenly.
Maintaining a consistent mechanical environment is essential for the accuracy of high-precision weighing and force measurement systems.