Investigation of gradient-enhanced damage evolution in viscoplastic plates under propagating disturbance



This work investigates gradient-enhanced damage evolution by performing a parameter study for the authors's finite element shell model [1], in which the free energy function is enhanced phenomenologically in terms of a non-local damage variable and its gradient on the mid-surface of shell structures. This enhancement gives rise to an introduction of gradient parameters in terms of a substructure-related intrisic length-scale and a relationship between non-local and local damage variable. Based on the global displacement-force curves obtained from shock-tube tests on aluminium plate specimens, the gradient parameters are determined to validate the proposed shell model. The influence of spatial gradient of loading on the material behaviour within a macroscopic continuum element will be discussed through several examples. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)