Effects of the Strain Rate Sensitivity and Strain Hardening on the Saturated Impulse of Plates

Abstract

This paper studies the stiffening effects of the material strain rate sensitivity and strain hardening on the saturated impulse of elastic, perfectly plastic plates. Finite element (FE) code ABAQUS is employed to simulate the elastoplastic response of square plates under rectangular pressure pulse. Rigid-plastic analyses for saturated impulse, which consider strain rate sensitivity and strain hardening, are conducted. Satisfactory agreement between the finite element models (FEM) and predictions of the rigid-plastic analysis is obtained, which verifies that the proposed rigid-plastic methods are effective to solve the problem including strain rate sensitivity and strain hardening. The quantitative results for the scale effect of the strain rate sensitivity are given. The results for the stiffening effects suggest that two general stiffening factors 1 n and 2 n , which characterizes the strain rate sensitivity and strain hardening effect, respectively can be defined. The saturated displacement is inversely proportional to the stiffening factors (i.e. 1 n and 2 n ) and saturated impulse is inversely proportional to the square roots of the stiffening factors (i.e. 1 n and 2 n ). Formulae for displacement and saturated impulse are proposed based on the empirical analysis.

Nonlinear analysis of inter-island RoRo under impact: effects of selected collision’s parameters on the crashworthy double-side structures

“…where r Y is the yield stress, _ e is the strain rate, C and P are the Cowper-Symonds strain rate parameters [32], r o is the initial yield stress, b is the hardening parameter, E p is the plastic hardening modulus, E is the Young's modulus, and e p eff is the effective plastic strain. When the structure has been deformed enough subjected to collision load, it will eventually rupture and possibility of failure is high.…”

Impulse saturation in metal plates under confined blasts

“…There exists a large body of literature that deals with the analytical investigations of impulse saturation based on the framework of limit analysis [1,2,[4][5][6][7][8][9][10]. Early studies by Jones [4] reported the phenomenon that under rectangular or triangular pulse-pressure of a sufficiently long duration, a plate structure reaches its maximum transverse deflection well before the end of the pressure pulse, and this permanent deflection remains unchanged despite continued loading by the pressure pulse.…”

“…After Zhao [5,6] defined the terminology 'impulse saturation' and investigated this phenomenon for rigid perfectly-plastic beams under rectangular pulse pressure, the term impulse saturation phenomenon has been widely used. In recent years, Zhu, Yu et al [2,[7][8][9] systematically carried out saturation analysis for pulse-loaded beams and plates. Their analytical model has been evolving to be more accurate and comprehensive, i.e., many features have been considered over the years, such as the effect of travelling plastic hinge lines [2], effects of strain rate sensitivity and strain hardening [8], the effect of boundary condition [7], and arbitrary pulse shape [9].…”

“…In recent years, Zhu, Yu et al [2,[7][8][9] systematically carried out saturation analysis for pulse-loaded beams and plates. Their analytical model has been evolving to be more accurate and comprehensive, i.e., many features have been considered over the years, such as the effect of travelling plastic hinge lines [2], effects of strain rate sensitivity and strain hardening [8], the effect of boundary condition [7], and arbitrary pulse shape [9]. Yuan et al [3], on the other hand, employed an elasto-plastic analytical model [10] to study the impulse saturation for a fully clamped beam under blast loading.…”

Equivalent design pressure for ship plates subjected to moving slamming impact loads

“…It often causes damages to the local plate panels, as examined by Jones [23] and Zhu and Faulkner [15]. Recently, plastic deformations under various pressure pulses and the saturated impulse are studied by Zhu et al [38][39] and Bai et al [40]. For deadrise angles larger than about 30°, the spatial distribution of the slamming pressure does not vary much and the velocity of the pressure front is limited [41].…”