Response simulations of clamped circular steel plates under uniform impulse and effects of axisymmetric stiffener configurations

Abstract

The paper presents Finite Element Analysis (FEA) and simulations of large deformations and observed ductile fracture failure modes of clamped circular plates subjected to uniform impulsive loads using phenomenological failure models for damage initiation and progression. The proposed numerical setup is founded on a well-defined model of the constitutive material properties based on inverse FEA simulations of the uniaxial tension test for the calibration of the material and failure parameters. The presented numerical model using the tri-axiality weighted accumulated plastic strain damage model in conjunction with a progressive degradation scheme for the evolution and progression of failure in the structure, is calibrated from a single uni-axial tension test. Published experimental results of large plastic deformations, onset of thinning and tearing at the boundary for clamped steel circular plates subjected to uniformly loaded air blasts have been used to assess the performance and efficacy of the proposed numerical scheme and procedure, with inclusion of temperature effects due to plastic dissipation. Towards improvement in the predictions by the numerical model, a hybrid damage model involving a two part ductile fracture locus has been proposed, which shows excellent correlation with the experimental results presented in terms of non-dimensional parameters over a wide range of impulsive loading and stress states, covering all the relevant failure modes. The validated numerical model has further been used to study the effect of flat bar axisymmetric stiffener configurations on the structural response and failure mechanisms of clamped circular plates, which has not been seen in the literature so far. The numerical simulations have also been used to gain insights into the evolution of plastic zones, damage progression and predicted failure modes in circumferentially oriented transversely stiffened steel plates with increasing intensity of impulsive loads.