Plastic response and failure of rectangular cross-section tubes subjected to transverse quasi-static and low-velocity impact loads

• Punching and dynamic drop weight impact tests have been performed on rectangular cross-section tubes.
• The laboratory results are compared with numerical simulations.
• The results show that the impact location strongly influences the impact response of the tubes.
• The numerical results manage to describe the process of initiation and propagation of the material fracture.
• The crack initiation in both upper and lower walls is well described by the matrix of the infinitesimal strain tensors.

Quasi-static punching tests and dynamic drop weight impact tests have been performed to examine the plastic response and failure of clamped rectangular cross-section tubes struck transversely by a hemispherical indenter. The laboratory results are compared with numerical simulations. The span lengths of the tube specimens are 125 and 250 mm, and they are impacted at different locations along the span. The results show that the impact location strongly influences the impact response of the tubes. Since the tubes are fabricated with strain-rate-insensitive high strength steel, the experimental plastic response and failure are similar when the tubes are loaded statically or under low impact velocity. The experimental results are presented in terms of the force–displacement responses and the failure modes, showing a good agreement with the simulations performed by the LS-DYNA finite element solver. The numerical results manage to describe the process of initiation and propagation of the material fracture and provide detailed information to analyse the large inelastic deformation and failure of ship structural components subjected to impact loading. The deformation and failure characteristics of the tube specimens are well described on the basis of the failure modes of the beam and plate models. Moreover, the crack initiation in both upper and lower walls is well described by the matrix of the infinitesimal strain tensors and the deformed shape of the first failing element.