Coupled Simulations of Extreme Fluid-Structure Dynamics

  • Aune, Vegard (NTNU, Department of Structural Engineering)
  • Valsamos, Georgios (European Commission, EU-JRC, Ispra)
  • Casadei, Folco (European Commission, EU-JRC, Ispra)

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Fluid-structure interaction (FSI) simulations can be challenging for a number of reasons and are therefore often dependent on the application. One of these challenging applications is the simulation of blast-loading effects on flexible structures undergoing large deformations, possibly up to complete failure. Such simulations require robust and specific FSI algorithms. Recent advancements have managed to establish experimental and numerical frameworks allowing for detailed studies on the FSI during the dynamic response of blast-loaded steel plates. A combination of experiments and numerical simulations can therefore be used to obtain more insight into the underlying physics during extreme blast-structure interaction. This work presents ongoing research on the influence of FSI effects on the ductile crack growth in perforated, thin steel plates subjected to blast loading. To date, we do not fully know the importance of FSI effects in these loading scenarios. The use of thin steel plates allows for large, inelastic strains and ductile fracture. Such structures often require a fine mesh size to represent both the loading and the localization of damage and crack growth. Since the increase in CPU cost may be significant when uniformly refining the mesh, it is desirable to evaluate the capabilities of adaptive mesh refinement (AMR) in reducing the CPU cost and maintain the accuracy of the solution. This motivates studies on the performance of FSI- and damage-based AMR to predict the dynamic response and failure of coarsely meshed shell structures exposed to blast loading. Numerical simulations are conducted in the EUROPLEXUS software. It was found that the most important feature in predicting the observed fracture patterns was an accurate description of the blast loading during the FSI. Moreover, the use of immersed FSI algorithms in combination with finite volumes discretization of the compressible flow was found to provide very promising results.