V World Congress on Computational Mechanics - WCCM, Vienna (Austria). 07-12 July 2002
Summary:
Cohesive elements are surface elements, which hold together two sub-bodies meeting at an interface. The elements contain a set of nodal pairs, which interpolate the shape of the interface. The nodes in each pair occupy the same location in the reference configuration but are connected to each of the two sub-bodies. The difference in displacement between the nodes in each pair, when resolved into normal and tangential directions to the surface, describe the opening and sliding displacements, respectively. A cohesive law then gives the tractions, which resist separation/penetration and sliding along the interface. Cohesive elements provide a physically sound and computationally effective means of modeling decohesion and fracture processes. We propose to develop a class of two- and three-dimensional cohesive elements consisting of two quadrilateral faces. Thus, the opening displacements are described by bilinear interpolation within the element. Also, the element is fully compatible with - and may be used to bridge - two bulk elements. The ideas described in the previous paragraphs can be applied directly to evaluate the induced fatigue of an irregular transient load of short duration. Each peak of the history will be analyzed as a quasi-static load. Mixed mode, plasticity, sequence effects etc. are then perfectly monitored. For cyclic loads, with harmonic or numerous repetitions of irregular histories, the damage at each point will be considered a smooth function that can be extrapolated with a single-value expansion, given a certain increment of cycles. Then, the new global damage distribution and the new load level have to converge to a state of equilibrium, to be computed by the standard non-linear finite element schemes.
Keywords: Fracture, fatigue, crack growth, finite elements
Publication date: 2002-07-07.
Citation:
A. Andrés, F. Fernández, O. López-García, On the use of cohesive interface elements in fracture and fatigue, V World Congress on Computational Mechanics - WCCM, Vienna (Austria). 07-12 July 2002.
