Abstract: The present invention relates to a method of testing and/or monitoring structural adhesively bonded joints by the introduction of transducers into the stress or strain field effected by the movement of said adhesively bonded joints under load, such that the load transfer characteristics between the bonded materials and the adhesive can be recorded thus allowing the quantification of the integrity of the adhesive bond lines in such joints. The method assesses the integrity of the bond by comparing the difference in maximum and minimum ratios and curve perameters relating to stress and strain with those of the "at assembly" values.