Twenty-five years of evolution of SHM technologies

SHM technologies have evolved since the first IWSHM Conference, held in Stanford in September 1997, reaching in some cases a significant level of maturity and economic importance. The focus during the initial years was set on developing and demonstrating systems with a damage detection capability; proof of reliability is becoming a key theme in recent years, translating procedures already in usage in conventional NDE, as a requirement for SHM industrialization. For civil engineering applications, Operational Modal Analysis (OMA) and related items continues to be the dominant technique; whilst for thin stiffened shells, like aircraft structures, Guided Waves is the most notorious technology. Nevertheless, other technologies such as distributed fiber optic sensing, acoustic emission and nanoparticles-doped resins have demonstrated a significant potential. Looking into the near future, new algorithms and data processing techniques are most likely to deliver relevant advancements; drastic changes in sensor technologies seem unlikely. As in any engineering field, the development of simulation tools will remain critical to enrich the variety of experiments without prohibitive costs. The development of standards is a key factor for the acceptance and widespread usage by industry.