Diagnosis apparatus, diagnosis method, and computer-readable recording medium

A diagnosis method comprising:

• generating pieces of target vibration information indicating mode vector vibrations in a target mode among vibrations of a structure that are measured in a diagnosis period using a plurality of sensors mounted on the structure during vibration tests of the structure and pieces of reference vibration information indicating the mode vector vibrations in the target mode among the vibrations of the structure that are measured that are measured using the plurality of sensors mounted on the structure during the vibration tests of the structure in a reference period that is different from the diagnosis period;
• generating reference relationship information that is an index indicating a similarity degree between the pieces of reference vibration information and comparative relationship information that is an index indicating a similarity degree between the pieces of reference vibration information and the pieces of target vibration information;
• calculating a distribution of the reference relationship information and a distribution of the comparative relationship information;
• and
• diagnosing that a change has occurred in the structure between the diagnosis period and the reference period when there is a distribution difference equal to or larger than a predetermined difference between the distribution of the reference relationship information and the distribution of the comparative relationship information.

A non-transitory computer-readable recording medium having recorded therein a diagnosis program for causing a computer to carry out:

• generating pieces of target vibration information indicating mode vector vibrations in a target mode among vibrations of a structure that are measured in a diagnosis period using a plurality of sensors mounted on the structure during vibration tests of the structure and pieces of reference vibration information indicating the mode vector vibrations in the target mode among the vibrations of the structure that are measured in a reference period that are measured using the plurality of sensors mounted on the structure during the vibration tests of the structure that is different from the diagnosis period;
• generating reference relationship information that is an index indicating a similarity degree between the pieces of reference vibration information and comparative relationship information that is an index indicating a similarity degree between the pieces of reference vibration information and the pieces of target vibration information;
• calculating a distribution of the reference relationship information and a distribution of the comparative relationship information;
• and
• diagnosing that a change has occurred in the structure between the diagnosis period and the reference period when there is a distribution difference equal to or larger than a predetermined difference between the distribution of the reference relationship information and the distribution of the comparative relationship information.