Structural damage detection

An assessment apparatus for assessing a structural defect presence in a structure, the apparatus comprising:

• a communication unit configured to receive first data relating to a first image of a surface of the structure under a first loading condition, and to receive second data relating to a second image of the surface of the structure under a second loading condition;
• and
• a processor configured to:
• assign a position matrix on the captured first image;
• obtain a deformation matrix comprising a deformation value at each position of the position matrix by using an image correlation technique on the first and second images, and by comparing deformation of corresponding parts of the surface captured therein;
• calculate a strain matrix using the obtained deformation matrix;
• determine a micro-crack to be present at a position if an element of the strain matrix representing the strain at the position is greater than or equal to a predetermined critical damage strain value, wherein the predetermined critical damage strain value is a strain value at which a micro-crack is detected or predicted to appear and/or propagate;
• determine a potential damage zone which is a set of all neighbouring positions determined to have a micro-crack present;
• obtain a potential damage strain matrix by selecting the elements relating to the potential damage zone from the strain matrix;
• determine at least one local maximum strain value for each row and/or column of the potential damage strain matrix if an element therein represents a strain with greater value than both the previous and subsequent elements in the potential damage strain matrix;
• and
• determine a crack propagation path to be a collection of positions related to the at least one local maximum strain values.

A computer program product including one or more non-transitory computer readable mediums encoded with instructions that when executed by one or more processors cause a process to be carried out for assessing a structural defect presence in a structure, the process comprising:

• receive first data relating to a first image of a surface of the structure under a first loading condition, and receive second data relating to a second image of the surface of the structure under a second loading condition;
• assign a position matrix on the captured first image;
• obtain a deformation matrix comprising a deformation value at each position of the position matrix by using an image correlation technique on the first and second images, and by comparing deformation of corresponding parts of the surface captured therein;
• calculate a strain matrix using the obtained deformation matrix;
• determine a micro-crack to be present at a position if an element of the strain matrix representing the strain at the position is greater than or equal to a predetermined critical damage strain value, wherein the predetermined critical damage strain value is a strain value at which a micro-crack is detected or predicted to appear and/or propagate;
• determine a potential damage zone which is a set of all neighbouring positions determined to have a micro-crack present;
• obtain a potential damage strain matrix by selecting the elements relating to the potential damage zone from the strain matrix;
• determine at least one local maximum strain value for each row and/or column of the potential damage strain matrix if an element therein represents a strain with greater value than both the previous and subsequent elements in the potential damage strain matrix;
• and
• determine a crack propagation path to be a collection of positions related to the at least one local maximum strain values.