Coupling continuous damage and debris fragmentation for energy absorption prediction by cfrp structures during crushing

Abstract

Energy absorption during crushing is evaluated using a thermodynamic based continuum damage model inspired from the Matzenmiller-Lubliner-Taylors model. It was found that for crash-worthiness applications, it is necessary to couple the progressive ruin of the material to a representation of the matter openings and debris generation. Element kill technique (erosion) and/or cohesive elements are efficient but not predictive. A technique switching finite elements into discrete particles at rupture is used to create debris and accumulated mater during the crushing of the structure. Switching criteria are evaluated using the contribution of the different ruin modes in the damage evolution, energy absorption, and reaction force generation.

Stabilization of the Numerical Priming to Stabilization Phenomenon in the Crushing of a Composite Panel Using Local and Diffuse Damage Laws

“…As far as we are concerned, for unidirectional CFRP laminates, it has been proved that the trigger and the angles of contact have a great effect on the initiation of the crushing process. Furthermore, the mean crushing force depends considerably to what happens in the few instants of the contact between the chamfered structure and the obstacle [4,6,[16][17]. This influence is due to the kind of material and the evolution of the contact conditions between the structure boundaries and the obstacle [18][19].…”

“…Based on observations made from experimental testing campaigns, different mechanical models were proposed in previous studies [8,[16][17]. The basic model used in this work is the nonlinear elastic anisotropic homogenized continuum damage mechanics model developed in the frame of the irreversible thermodynamics [17].…”

“…The basic model used in this work is the nonlinear elastic anisotropic homogenized continuum damage mechanics model developed in the frame of the irreversible thermodynamics [17]. In order to circumvent the problems coming from the local compression at the contact on the ground, the elements that face the ground are changed the material model into the MCS and FFC models to follow the strategy proposed by [16].…”

“…The continuous Diffuse Damage Model has been developed on the basis of the previous work of Ylias [17]. Enhancements have been proposed to adapt the model to the strategy described on Figure 2.…”

“…Energy release follows a linear tension to opening relationship. In order to limit the mesh size effect in the opening crack propagation, a scale factor  is introduced [17].…”