Experimental and numerical plastic response and failure of pre-notched transversely impacted beams

Abstract

Abstract Experimental drop weight impact tests have been performed to examine the dynamic plastic response and failure of clamped pre-notched beams struck transversely by a mass with a spherical indenter. The laboratory results are compared with numerical simulations. The machined notches are 2.0 and 4.0 mm in depth, and the beams are impacted at the mid-span and at one-quarter from the support. The experiments are conducted using a fully instrumented impact testing machine. The obtained force–displacement responses show a good agreement with the simulations performed by the LS-DYNA finite element solver. The simulations aim at proposing techniques for defining the material characteristics and the boundary conditions of numerical models that analyse the large inelastic deformation and failure of ship structural components subjected to impact loading. The finite element model includes the experimental boundary condition so as to simulate small axial displacements of the specimen at the supports. The strain hardening of the material is defined using experimental data of the quasi-static tension tests and the strain rate sensitivity is evaluated using standard coefficients of the Cowper–Symonds constitutive model. The Cowper–Symonds model is also selected to estimate the dynamic critical failure strain by the use of the quasi-static failure strain predicted by numerical simulations of the tensile tests. Although the dynamic properties of the material should determine the response of the impacted specimens, the results show that the plastic response until failure is highly sensitive to the amount of restraint provided at the supports.