System and method for determining lifetime of wind turbine blade

A system for monitoring stress on a wind turbine blade during loading, the system comprising:

• a camera configured to capture a plurality of images at respective locations of the wind turbine blade while the wind turbine blade is subject to loading;
• and
• a processor containing instructions that when executed cause the processor to perform the following steps:
• receive a plurality of temperature measurements from the camera;
• and
• calculate stress within the wind turbine blade based upon the temperature measurements by correlating the temperature change measured via the captured images with a known stress level associated with such temperature change;
• compare the calculated stress with a respective theoretical stress in a finite element model of the wind turbine blade to detect stresses that indicate damage within the wind turbine blade;
• use the indicated damage during loading to predict lifetime of the wind turbine blade;
• and
• alert an operator in event that the calculated stress at one or more of the respective locations is above a pre-determined limit.