A method of determining a distance to a discontinuity within an object may include the steps of: a) generating a continuous, frequency modulated input signal having a predetermined frequency range and a frequency ramping speed using a signal generator and splitting the input signal into at least a test signal and a reference signal; b) generating an input sound wave based on the test signal and continuously introducing the input sound wave into the object using a transmitter and simultaneously receiving a reflected sound wave reflected by a discontinuity within the object and generating a corresponding return signal using a receiver; c) determining a frequency difference value based on a comparison of the reference signal and the return signal using a controller; and d) automatically determining a distance from the transmitter to the discontinuity within the object based on at least the frequency difference value and the frequency ramping speed.

To easily detect a crack having occurred in a steel material. A current measurement device 10 measures a value of a current flowing through a target steel material 100 that is immersed in an electrolyte aqueous solution 30 and applied with tensile stress while subjected to hydrogen charging, and a device 20 for detecting the occurrence of a crack or the like uses the measured current value to determine the occurrence of a crack in the target steel material 100 when the amount of change in the current flowing through the target steel material 100, the change rate of the amount of change in the current, or the change rate of the change rate of the amount of change in the current exceeds a threshold value. The device 20 for detecting the occurrence of a crack or the like determines the occurrence of a crack in the steel material when the change rate of the change rate of the amount of change in the current is less than a negative value of an absolute value of the threshold value, and determines the occurrence of fracture in the steel material when the change rate exceeds the absolute value of the threshold value.

Disclosed are a hole expansion ratio testing device, a hole expansion ratio testing method, and an operation program. The hole expansion ratio testing device includes a chucking unit configured to chuck a plate member having a hole, a punching unit inserted into the hole and configured to expand the hole, an image acquisition unit configured to acquire an image of the hole expanded by the punching unit, and an analysis unit configured to extract an interest area corresponding to the hole from the acquired image, linearize the interest area, and provide information on a crack as a blob changes due to the linearization.

Disclosed are a hole expansion ratio testing device, a hole expansion ratio testing method, and an operation program. The hole expansion ratio testing device includes a chucking unit configured to chuck a plate member having a hole, a punching unit inserted into the hole and configured to expand the hole, an image acquisition unit configured to acquire an image of the hole expanded by the punching unit, and an analysis unit configured to extract an interest area corresponding to the hole from the acquired image, linearize the interest area, and provide information on a crack as a blob changes due to the linearization.

A corrosion monitoring system includes one or more objects coupled to respective portions of a transformer tank. The one or more objects are configured to corrode before the respective portions of the transformer tank. At least one optical sensor is coupled to each of the objects. The at least one optical sensor has an optical output that changes in response to strain of the object. An analyzer is coupled to the at least one optical sensor. The analyzer is configured to perform one or more of detecting and predicting corrosion of the transformer tank based on the output of the at least one optical sensor.

A corrosion monitoring system includes one or more objects coupled to respective portions of a transformer tank. The one or more objects are configured to corrode before the respective portions of the transformer tank. At least one optical sensor is coupled to each of the objects. The at least one optical sensor has an optical output that changes in response to strain of the object. An analyzer is coupled to the at least one optical sensor. The analyzer is configured to perform one or more of detecting and predicting corrosion of the transformer tank based on the output of the at least one optical sensor.

The eddy current flaw detection apparatus includes: a pair of detecting coils 10a, 10b arranged in coaxial and spaced relation with a specimen 3; and a bridge circuit two sides of which are constituted by the detecting coils so that magnetic fields generated by these detecting coils 10a, 10b are in opposite phases to each other. A pair of exciting coils 11a, 11b are arranged coaxially with the detecting coils 10a, 10b in a manner to sandwich the pair of detecting coils 10a, 10b therebetween. A distance D between the detecting coil and the exciting coil adjacent thereto is set to a distance where a vibrational noise signal excited in the exciting coil and detected by its adjacent detecting coil is in opposite phase to that of a vibrational noise signal excited in the detecting coil and detected by the detecting coil.

The eddy current flaw detection apparatus includes: a pair of detecting coils 10a, 10b arranged in coaxial and spaced relation with a specimen 3; and a bridge circuit two sides of which are constituted by the detecting coils so that magnetic fields generated by these detecting coils 10a, 10b are in opposite phases to each other. A pair of exciting coils 11a, 11b are arranged coaxially with the detecting coils 10a, 10b in a manner to sandwich the pair of detecting coils 10a, 10b therebetween. A distance D between the detecting coil and the exciting coil adjacent thereto is set to a distance where a vibrational noise signal excited in the exciting coil and detected by its adjacent detecting coil is in opposite phase to that of a vibrational noise signal excited in the detecting coil and detected by the detecting coil.

To estimate a fracture starting point of steel due to hydrogen embrittlement with high accuracy. A steel fracture starting point estimation device includes a hydrogen concentration distribution calculation unit adapted to calculate a hydrogen concentration distribution in steel-to-be-estimated when the steel fractures due to hydrogen embrittlement; a local critical hydrogen content calculation unit adapted to calculate critical hydrogen content at which the steel-to-be-estimated fractures due to hydrogen embrittlement; and a fracture starting point estimation unit adapted to read the hydrogen concentration distribution out of a storage unit. To estimate, calculate, from the hydrogen concentration distribution, a location in the steel in which hydrogen concentration of the critical hydrogen content is distributed, and designate the location in the steel as the fracture starting point of the steel-to-be-estimated.

To estimate a fracture starting point of steel due to hydrogen embrittlement with high accuracy. A steel fracture starting point estimation device includes a hydrogen concentration distribution calculation unit adapted to calculate a hydrogen concentration distribution in steel-to-be-estimated when the steel fractures due to hydrogen embrittlement; a local critical hydrogen content calculation unit adapted to calculate critical hydrogen content at which the steel-to-be-estimated fractures due to hydrogen embrittlement; and a fracture starting point estimation unit adapted to read the hydrogen concentration distribution out of a storage unit. To estimate, calculate, from the hydrogen concentration distribution, a location in the steel in which hydrogen concentration of the critical hydrogen content is distributed, and designate the location in the steel as the fracture starting point of the steel-to-be-estimated.