Abnormality determination device and abnormality determination method

An abnormality determination device that determines an abnormality of an inducer used for a turbo pump of a rocket, the abnormality determination device comprising:

• a pressures sensor provided at an input side of the inducer;
• a pressure acquisition unit configured to acquire pressure measured by the pressure sensor provided at an input side of the inducer;
• a stress-response acquisition unit configured to acquire a stress response indicating a temporal change in stress applied to the inducer;
• an accumulated-fatigue-damage-degree calculation unit configured to calculate an accumulated fatigue-damage degree of the inducer based on the stress response;
• a lifetime-consumption-rate calculation unit configured to calculate a lifetime consumption rate that is a changing rate of the accumulated fatigue-damage degree with respect to time;
• a determination unit configured to determine the abnormality of the inducer based on the accumulated fatigue-damage degree and the lifetime consumption rate;
• and
• an output unit configured to transmit a stop instruction to the rocket so as to safely stop operation of the rocket when the determination unit indicates the abnormality, wherein
• the inducer is used only for a predetermined use time per flight of the rocket,
• the stress-response acquisition unit is configured to convert a pressure response indicating a temporal change in the pressure into the stress response using a transfer function that defines the relation between the pressure measured by the pressure sensor and a distortion of the inducer, and
• the determination unit predicts, based on the accumulated fatigue-damage degree and the lifetime consumption rate, whether the accumulated fatigue-damage degree exceeds a lifetime limit defining a limit of a damage degree of the inducer during the operation, and determines that the inducer is abnormal when predicting that the accumulated fatigue-damage degree exceeds the lifetime limit during the operation.