Digital Twin supported Structural Health Monitoring of Test Rigs for Wave Energy Applications

Abstract

The objective of this paper is to document the development and application process of a generic Digital Twin (DT) test rig model for Structural Health Monitoring (SHM). The test rig used for Wave Energy Converter (WEC) component testing is represented by a Component Mode Synthesis (CMS) reduced assembly FEM applicable to real time execution. The Finite Element (FE) simulation model can be exported as a Digital Twin model through a Functional Mockup Unit (FMU) to the digital framework for Dual Hardware in the Loop (DHIL) simulations. The simulation model is also used to generate a Reduced Order Model (ROM). A digital framework can be configured to simultaneously execute and sample data from physical and virtual FMU/ROM sensors on the WEC test rig during tests. The digital twin model can run in both real time and off-line mode. In real time mode, the physical test rig excitations are sampled and streamed to the digital twin model using open software solutions. Real-time stress and fatigue analysis for the selected load cases can be conducted using virtual strain gauges located at hot spots and identified by a virtual brittle lacquer technique. The streamed data is also buffered and stored on (csv) files for later digital twin off-line execution. The digital framework supporting data sampling, visualization, analytics, event handling, anomaly detection and digital twin execution is based on open-source Python and Streamlit scripts. The digital twin model is prepared and executed by the open-source FEDEM software [Stranden Ø. et al.,2023)] based on both live streaming and historical data. A new two-step FMU and ROM process is developed and applied for DHIL execution.