A method of monitoring a structure, the method comprising positioning one or more strain gauges on the structure; acquiring strain data with the gauges(s); analyzing the strain data to determine whether the structure has undergone plastic deformation; and providing an output in accordance with the analysis. By analyzing the strain data to determine whether the structure has undergone plastic deformation, a more reliable determination can be made of whether the structure has experienced an excessively high transient loading event such as a hard landing of an aircraft, or the lifting of an excessive load by a crane.