A constitutive model is presented for large strain deformation of polycarbonate (PC) at high strain rates (above 102 s−1). The proposed model considers the primary process (α) and the two secondary rate‐activated processes (β and γ). It is shown that the secondary transitions in the material affect the yield and post yield behavior of the material at high strain rates. The constitutive model has been implemented numerically into a commercial finite element code through a user material subroutine. The experimental results, obtained using a split Hopkinson pressure bar, are supported by dynamic mechanical thermal analysis (DMTA) and DSR (Decompose/Shift/Reconstruct) method. These are employed to gain understanding of the material transitions, and to further the linkages between material viscoelastic, yield, and stress–strain behavior. Comparison of model predictions with experimental data demonstrates the ability of model to capture the characteristic features of stress–strain curve of the material such as initial linear elasticity, global yield, strain softening, and strain hardening at very high strain rates (up to 10,000 s−1). POLYM. ENG. SCI. 2013. © 2012 Society of Plastics Engineers

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The dynamic plastic response of structures under blast loading and underwater explosion has found important applications in the design of energy-absorbing and collision protection devices. This paper presents the results of analytical and experimental studies on the response of steel and aluminium circular plates in two different media of air and water. Results of experimental observation of fully clamped plates have been presented. The results obtained are compared with existing empirical relations, a theoretical procedure, and a modified relation offered by Wierzbicki and Symonds. Comparing the experimental and theoretical results, it was observed that considering strain rate effect in the theoretical procedure is essential in obtaining a more accurate prediction of the deflection of the plate. The reasonable agreement between experimental results and relations proves the validity of the proposed predictions, especially when strain rate effect is considered. Since, in the case of air-blastloaded plates, the deviation from experimental results was noticeable, a new relation for dynamic plastic response of circular plates is suggested, which is based on Zhao damage number. Furthermore, the effect of material and medium is investigated.

This article presents the results of experimental and analytical studies on the response of steel and aluminium square plates with different thicknesses subjected to blast loading. Based on the blast wave details and the scaling law for explosions, a method of determining the blast load is proposed in which ballistic pendulums do not need to be utilized for obtaining the blast wave impulses. The loads applied to the plates are assumed to be the quasi-exponential pressure pulses, which are the same as the explosion overpressures. The theoretical solutions are presented using a rigid, perfectly plastic idealization and are exact within the context of dynamic plasticity. The dynamic energy imparted to structures can cause material failure. The presented investigation considers such a failure for fully clamped plates subjected to a blast loading idealized as an initial velocity distributed uniformly throughout the area. The predicted deflections and general failure modes of the plates are presented and compared with experimental results. Moreover, a numerical simulation is carried out by modelling an FSI (fluid–solid interaction) problem. Results are compared with each other and a better agreement between numerical results with experimental ones is observed.

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