Assessment and Reduction of Uncertainties in Operational Modal Analysis (RUN-OMA): Supplemental Data

The RUN-OMA project developed a novel methodology to objectively and transparently evaluate the quality of results from Operational Modal Analysis (OMA) — a technique used to determine the modal parameter of structures, such as natural frequencies, damping ratios and mode shapes. These properties are benefitial for assessing structural integrity and durability. Until now, the evaluation of such results has often relied on subjective judgment and expert experience, posing the risk of unnoticed inaccuracies affecting further analyses. The project's primary goal was to create a scientifically sound and automatable method for quantifying Polymorphic Uncertainties — encompassing both aleatory (random) and epistemic (knowledge-based) uncertainties arising throughout the measurement and analysis chain, such as sensor noise, unknown analysis parameters, or undetermined signal properties. At the heart of the project lies a comprehensive process model that maps all stages from structural excitation and vibration measurement to modal analysis. Based on this, methods were developed for polymorphic uncertainty quantification, assessment of signal suitability with respect to an OMA, and cross-validation of identified dynamic systems. These methods enable a more reliable evaluation of OMA results, leading to better-informed decisions in structural assessment. The developed techniques were implemented in open-source software and applied to realistic numerical models. All tools and results are publicly documented and accessible. The project thus makes a significant contribution to the transparency, reproducibility, and advancement of modern analysis methods in structural dynamics.