AN ASSESSMENT ON THE FAILURE ANALYSIS OF LAYERED STRUCTURES WITH VARIABLE KINEMATICALDESCRIPTION
Annotatsiya
Further advances in the use of laminated composites structures for aerospace applications are subordinate to a better understanding of their failure mechanisms. Proper failure analysis of composite layered structures is currently an unsolved issue. In fact, failure mechanisms are very different from those pertaining traditional metallic structures. The combination of various interfaces (fibers, matrix, layers) at a macro scale level would require a local dedicated analysis in order to establish the initiation of failure mechanisms of a fiber/crack in the matrix or the delamination between two different layers. In order to perform a reasonable failure analysis of composite layered structures by referring to plate modeling, the two following independent requirements should be satisfied: 1. Displacement, strain and stress fields have to be calculated with high precision; 2. An accurate and consistent failure criteria should be applied. Point 1 can be fulfilled by employing advanced/higher order plate kinematical descriptions, using appropriate constitutive relations and referring to an appropriate variational statement. Corresponding governing equations can be solved by applying the finite element method. Extensive literature has been produced in the last decade on this subject. More specifically, the first author assessed the so-called Carrera Unified Formulation (CUF) [1-5]. CUF permits to solve the problem by considering a generic kinematical description, which can be also defined by the user, according to the required accuracy. Concerning point 2, it should be emphasized that failure of composites is very complicated with respect to metals. Many failure criteria for composites have been proposed in the recent past. First Hashin [6-7] established the need for failure criteria that are based on failure mechanisms. Afterward, Sun et al. [8] proposed an empirical modification to Hashin’s criterion. The World Wide Failure Exercise (WWFE), conceived in 1991 at St Albans (UK) and conducted by Hinton and Soden, clarified that the Puck failure criteria [9-10] is the one which better fits experimental results. As a consequence, referring to Puck’s theory and after some additional enhancements, Davila and Camanho proposed the LaRC03 failure criteria, which could be considered the best two-dimensional criterion currently available for