THREE-DIMENSIONAL PELLET-CLADDING MECHANICAL INTERACTION THROUGH COHESIVE MODEL IN DIONISIO 3.0

GOLDBERG, EZEQUIEL; ALEJANDRO SOBA

Congreso; ENIEF; 2019

In order to extend the capabilities of the DIONISIO code to three-dimensional domains, wehave included a new algorithm to simulate the contact between pellet and cladding and between pelletsbased in Cohesive Finite Elements. In addition to dividing the rod in a user-defined number of segments,the user can now choose the dimensionality of the domain in which a representative pellet-gap-claddingsystem is solved. This new model can determine the moment in which two surfaces begin to experiencecontact and define the evolution of the contact force, including separation of the surfaces and successivecontacts. Moreover, it could provide a solution to simulate asymmetric problems concerning theeccentricity of the pellet and cladding, asymmetries in temperature distribution due to the position of arod in a bundle, especially in accident conditions, or the presence of a defect in the pellet, among others.We present our results testing this kind of contact element, showing improvements over the previoustwo-dimensional axisymmetric model using Lagrange multipliers and comparing our results withexperiments displaying a high correlation so as to validate the concept.