From June 1st until July 31st we had the pleasure to host two visiting scientists from Clemson University, South Carolina, USA, at the Collaborative Research Center (SFB) 805 in Darmstadt.

Successful exchange between Clemson University and the SFB 805

Shyla Kupis and Rob Locke are currently PhD students at Clemson University and are working on uncertainty quantification in their research. The exchange was jointly initiated by Dr. Roland Platz from the SFB 805 and Dr. Sez Atamturktur, Professor at Penn State University for Architectural Engineering and former Professor at Clemson University. In the framework of this collaboration, also Christopher Gehb from the SFB already spent two months as a visiting PhD student at Clemson University in 2017.

Pic1: Rob Locke and Shyla Kupis discuss the spring-damper system of MAFDS

The primary goal of Shyla’s and Rob’s research stay was to evaluate the uncertainty in the mathematical modelling of the modular active spring-damper system (MAFDS), the SFB Demonstrator, in order to investigate uncertainty aspects in a load-bearing structural system and its dynamic response. Initially, output measurements of the MAFDS like forces and accelerations were performed to study its static and dynamic behaviour under different operating conditions. Subsequently, the spring-damper system’s stiffness and damping curves were fitted using three different mathematical regression models, resulting in nine different model combinations to capture the dynamics of the modular spring-damper system within the MAFDS. To prepare the models for uncertainty quantification, the number of calibration parameters of the models was first reduced by using a sensitivity analysis. The models were then subject to an uncertainty quantification process based on Bayesian inference. While Rob used a method that fits the measurements to a Gaussian process model, Shyla employed a delayed-acceptance adaptive metropolis algorithm. The analysis is ongoing and the results will be presented in January at the International Modal Analysis Conference (IMAC) in 2019. The SFB team will greatly benefit from their work and expertise in uncertainty quantification. Regarding this fruitful outcome, it is planned to continue and deepen the cooperation further.

The research group of System Reliability, Adaptive Structures and Machine Acoustics (SAM) thanks the German Research Foundation (DFG) for funding Shyla’s and Rob’s stay with the SFB 805.

Pic2: Shyla Kupis and Rob Locke with members of the SFB 805/ SAM at TU Darmstadt: Roland Platz, Max Schäffner, Shyla Kupis, Christopher Gehb, Robert Feldmann, Jonathan Lenz and Rob Locke (from left to right).