Download or read book An Interface Damage Model for the Simulation of Delamination Under Variable-Mode Ratio in Composite Materials written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-29 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A thermodynamically consistent damage model for the simulation of progressive delamination under variable mode ratio is presented. The model is formulated in the context of the Damage Mechanics (DM). The constitutive equations that result from the variation of the free energy with damage are used to model the initiation and propagation of delamination. A new delamination initiation criterion is developed to assure that the formulation can account for changes in the loading mode in a thermodynamically consistent way. Interfacial penetration of two adjacent layers after complete decohesion is prevented by the formulation of the free energy. The model is implemented into the commercial finite element code ABAQUS by means of a user-written decohesion element. Finally, the numerical predictions given by the model are compared with experimental results.Turon, Albert and Camanho, Pedro P. and Costa, Josep and Davila, Carlos G.Langley Research CenterCOMPOSITE MATERIALS; DELAMINATING; MATHEMATICAL MODELS; DAMAGE; THERMODYNAMICS; SIMULATION; CONTINUUM MECHANICS; FINITE ELEMENT METHOD; FREE ENERGY; COMPUTER PROGRAMS; BOUNDARY VALUE PROBLEMS; KINEMATICS; DISPLACEMENT; DEBONDING (MATERIALS); DISCRETIZATION (MATHEMATICS)