a target comprising a set of parallel lines in the form of a one-dimensional barcode, two of the parallel lines being chosen as end lines, and a gage length defined by and perpendicular to the end lines, the target being adapted for association with a body for which at least one of strain and fatigue damage is to be calculated in such a way that deformation of the gage length and deformation under load of the body with which the target is associated bear a one-to-one relationship, and being adapted to emit a detectable physical quantity, wherein the one-dimensional barcode is based on the Code 39 barcode standard, and includes start and stop characters and a sequential string of a plurality of intermediate characters that hold the actual coded information, each character being defined by a total of nine bars and spaces;

a sensor compatible with and adapted to pre-process the detectable physical quantity emitted by the target and output data representing the physical quantity;

means for analyzing the data output by the sensor to define the gage length of the target; and

means for calculating at least one of the strain and the fatigue damage on the body directly, based on the pre-processed and analyzed data.