Structural Health Control—A Comprehensive Concept for Observation and Assessment of Damages Applied on a Darrieus Wind Turbine

Abstract

This article presents an overarching concept, to observe and to assess structural damages, applied on a H-Darrieus wind turbine. This novel concept is more than Structural Health Monitoring (SHM) and is known as Structural Health Control (SHC). The SHC concept analyses the structure, identifies the damage and records the acting load as well as the usage parameters of the structure. Furthermore, it assesses the identified damages, followed by a damage prognosis and then proposes an optimal repair solution for the structure. All these processes are implemented in different modules in the SHC concept and are realized as a feedback control loop (see Fig.1). This feedback control loop ensures the stability of repaired structures. However, this comprehensive concept enables us to monitor and assess the damages of different structures, e.g. bridges, aircraft structures, automotive structures and wind turbines. Compared with the well-known horizontal wind turbines the idea of the SHC concept on a complex vertical wind turbine so called H-Darrieus wind turbine (see Fig. 3) is being presented. Based on analytical results, a Finite Element model is validated on analytical considerations and the subsequent structural analysis, which is embedded in the SHC, identifies the most critical areas on the turbine. Each of the critical areas can be an initiation of damage. Just these remaining areas have to be observed by the SHC concept on a H-Darrieus wind turbine structure. However, the novel SHC concept detects the damage in the critical regions of the H-Darrieus wind turbine, which were proposed from the Structural Analysis. Moreover, a procedure to record a load spectrum for vertical wind turbines is proposed.