Modelling Strategies for Simulating Delamination and Matrix Cracking in Composite Laminates

Abstract

The composite materials are nowadays widely used in aeronautical domain. These materials are subjected to different types of loading that can damage a part of the structure. This diminishes the resistance of the structure to failure. In this paper, matrix cracking and delamination propagation in composite laminates are simulated as a part of damage. Two different computational strategies are developed: (i) a cohesive model (CM) based on the classical continuum mechanics and (ii) a continuous damage material model (CDM) coupling failure modes and damage. Another mixed methodology (MM) is proposed using the contin uous damage model for delamination initiation and the cohesive model for 3D crack propa gation and mesh openings. A good agreement was obtained when compared simple charac terization tests and corresponding simulations.

Modelling Strategies for Predicting the Residual Strength of Impacted Composite Aircraft Fuselages

“…The cohesive model (CM), presented by Lachaud et al [16], has been used to compute the damage resistance of [−45, 45, 0, 90, 0 2 , −45, 45, 0] s T800S/M21e samples. In previous work, the matrix cracking developed in multidirectional composite laminates loaded in tension is investigated by a finite element model [17].…”

“…This contact becomes active when a cohesive element is deleted. The used material data for the elastic plies and for the cohesive elements are found by Lachaud et al [16] and are summarized in Tables 1 and 2. The support is considered rigid (i.e. non-deformable), and constrained in all directions while the projectile is only constrained in x-and y-directions.…”

“…Delamination discontinuities are created by killing the cohesive elements that have failed. Indeed, the failure is obtained when damage reaches a value of 1 [16]. By plotting the cohesive elements for a damage variable varying between 0.9 and 1.0 (0.9<d<1.0), a bounding box representing the delamination area is obtained ( Fig.…”

“…The (CDM) model is used in each layer with the corresponding angle of fibres. The material Table 2 Data set for the proposed model and for T800S/M21e UD laminate defined by Lachaud et al [16] data is given in Table 2. The model does not distinguish between different tensile or compressive modulus; a "flexural modulus" (E f =112 GPa) is used to replace the axial modulus.…”

“…The outputs of the model that can be compared with C-Scan results are accumulated damage variables. The d 12 damage defined in the model of Lachaud et al [16] has been chosen here. It is also possible to draw the proportion of contribution of the different 5 failures modes.…”