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Session: Poster pitches day 1
Session starts: Monday 26 June, 09:50
Presentation starts: 09:50

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Jordy Schönthaler (University of Twente)
Bojana Rosic (University of Twente)
Dario Di Maio (University of Twente)

Abstract:
In the transition to a climate-neutral economy, composite materials can play a big role due to their high strength-to-weight ratio. However, reliable fatigue evaluation methods must be found to ensure long-term integrity of the designs. In aid, a digital-twin framework will be built to predict the residual lifetime of composite materials subjected to vibration fatigue. Previous research [1],[2] has shown applications of near-resonance fatigue testing. This shows a phase degradation up to a critical event, causing a sudden stiffness drop. This sudden stiffness drop can be used for two important parameters. The first parameter is the crack propagation throughout the composite material for the phase degradation up to the sudden stiffness drop, and the second parameter is a failure criterion at the point of the sudden stiffness drop. The crack propagation can be used to create Paris’ Law, containing material parameters. This can be combined with the critical event to create an SN-curve for the material, where the rapid delamination indicates failure. The experimental results obtained from the near-resonance testing will be used as input parameters for the digital-twin framework that will be created. This framework will consist of a loop that contains the following steps: First, a modal analysis will be performed to extract natural frequencies. This will be used for a steady-state analysis at the natural frequency to get the deflection shapes of the material. This will be used in a static analysis to determine the stresses near the crack tip in the material. Then, a heat transfer analysis will be performed to simulate the heat generation in the material during vibration. Finally, the crack growth in the material will be updated. With a new crack length, the loop will be repeated to get the new natural frequency with the degraded stiffness. This framework can be used to predict the residual life of composite materials that are subjected to vibration fatigue. This can significantly speed up conventional fatigue testing methods for composite materials. [1] Magi et al., Composites Sci. & Tech., 132 (2016) 47-56. [2] Di Maio et al., I. J. Fatigue, 155(2022)106617.