A Phenomenological Cohesive Model of Ferroelectric Fatigue

Laboratori de Cà lcul Numèric, Departament de Matemà tica Aplicada III, Universitat Politècnica de Catalunya, E-08034, Barcelona, Spain
Acta Materialia (Impact Factor: 4.47). 02/2006; 54(4). DOI: 10.1016/j.actamat.2005.10.035
Source: OAI

ABSTRACT We develop a phenomenological model of electro-mechanical ferroelectric fatigue based on a ferroelectric cohesive law that couples mechanical displacement and electric-potential discontinuity to mechanical tractions and surface-charge density. The ferroelectric cohesive law exhibits a monotonic envelope and loading-unloading hysteresis. The model is applicable whenever the changes in properties leading to fatigue are localized in one or more planar-like regions, modelled by the cohesive surfaces. We validate the model against experimental data for a simple test configuration consisting of an infinite slab acted upon by an oscillatory voltage differential across the slab and otherwise stress free. The model captures salient features of the experimental record including: the existence of a threshold nominal field for the onset of fatigue; the dependence of the threshold on the applied-field frequency; the dependence of fatigue life on the amplitude of the nominal field; and the dependence of the coercive field on the size of the component, or size effect. Our results, although not conclusive, indicate that planar-like regions affected by cycling may lead to the observed fatigue in tetragonal PZT. Peer Reviewed Postprint (author's final draft)

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Available from: Irene Arias, Jan 08, 2014
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    • "For simulation of damage initiation and evolution the concept of cohesive zone models is quite efficient, when one or several possible damage paths with embedded cohesive elements can be introduced a priori. Arias et al. [8] made first adaptation of the classical exponential cohesive zone model to ferroelectric materials to simulate electric fatigue, whereby some physical simplifications were made. Consecutive simulations with cohesive zone elements but with piezoelectric bulk behavior were performed by Utzinger et al. [9] and Verhoosel and Gutiérrez [10]. "
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    • "The choice of crack boundary condition becomes relevant when modeling the failure in such materials through the discrete account of the strong discontinuities. Constitutive models allowing for discontinuities in the displacement field as well as in the electric potential along the finite element boundaries are developed in Arias et al. [1] and Verhoosel and Gutiérrez [66]. Simulations of cohesive fatigue effects in grain boundaries of a piezoelectric mesostructure are performed in Utzinger et al. [65]. "
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