Fluid-structure interaction (FSI) simulations pose significant challenges, particularly due to their strong dependency on the specific application. One example is the simulation of blast-loading effects on flexible structures, which may undergo large deformations, potentially leading to complete failure. These scenarios demand robust and tailored FSI algorithms. Recent advancements have introduced experimental and numerical frameworks that enable detailed investigations into the FSI phenomena occurring during the dynamic response of blast-loaded plates. The dynamic response of these structures can vary significantly based on both blast intensity and structural characteristics. Consequently, numerous methods have emerged to predict the loading conditions and structural responses in such extreme scenarios. Building on recent work on the FSI effects of blast-loaded plates, this study focuses on evaluating the performance of traditional computational methods in predicting the behaviour of slender, flexible structures under blast-like loading conditions. The primary aim is to investigate the dynamic response of cantilevers and slender beams during shock tube tests, with a particular emphasis on the role of FSI. Special attention is given to identifying feasible modelling simplifications that balance computational efficiency with simulation accuracy. To validate the computational approaches, physical experiments are employed as benchmarks. The numerical simulations are conducted using the EUROPLEXUS software. It was found that accurate modelling of the blast loading during FSI is important for predicting the observed deformation modes as well as the associated diffraction and drag phenomena. Furthermore, the use of immersed FSI algorithms, combined with finite volumes discretization for the compressible flow, demonstrated very promising results. These findings offer valuable insights for the design of safer and more resilient structures in withstanding blast events in urban environments.