A damage model for the simulation of delamination in advanced composites under variable-mode loading

Abstract

A thermodynamically consistent damage model is proposed for the simulation of progressive delamination in composite materials under variable-mode ratio. The model is formulated in the context of Damage Mechanics. A novel constitutive equation is developed to model the initiation and propagation of delamination. A delamination initiation criterion is proposed to assure that the formulation can account for changes in the loading mode in a thermodynamically consistent way.The formulation accounts for crack closure effects to avoid interfacial penetration of two adjacent layers after complete decohesion. The model is implemented in a finite element formulation, and the numerical predictions are compared with experimental results obtained in both composite test specimens and structural components.

A phantom node formulation with mixed mode cohesive law for splitting in laminates

“…We assume that the fracture energy of the material can be described properly with the phenomenological relation proposed for delamination by Benzeggagh and Kenane (1996), which has been applied in interface elements by Camanho et al (2003) and Turon et al (2006):…”

“…Delamination, i.e., failure between the plies, can then be modeled with interface elements (e.g., Turon et al 2006;Yang and Cox 2005). For failure inside the ply, numerous formulations have been proposed for stress based failure criteria, ranging from classical criteria by Tsai and Wu (1971) and Hashin (1980) to more recent ones by Schürmann (1998, 2002) and Dávila et al (2005).…”

Numerical analysis of high velocity impacts on unidirectional laminates

“…These requirements have propelled in the last decades the use of composite materials, particularly CFRP unidirectional laminates. In this context, the structural problem of high velocity impact of debris on aircraft components of composite materials has become a subject of intense interest [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16], not only from the point of view of experimental research [17][18][19] but also from the perspective of numerical simulation and virtual testing, given its potential for reducing the total cost of development of aeronautic structures [20][21][22][23][24][25][26]. These computational aspects are the subject of the present work, which deals with the development of a numerical methodology able to faithfully reproduce the behavior of carbon/epoxy laminates under high velocity impact of small debris.…”

Experimental analysis of normal and oblique high velocity impacts on carbon/epoxy tape laminates

“…In the next decade the number of articles regarding high velocity impacts on carbon/epoxy laminates grew substantially, and not always the main focus was experimental, many of them had a numerical [16][17][18][19][20][21] or an analytical point of view [22][23][24][25][26], which is not the main porpoise of the current work.…”