Strain injection techniques in dynamic fracture modeling

J. OLIVER,; A E. HUESPE; LLOVEAS-VALS O.; DIAS I.

COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2016 vol. 308 p. 499 - 534

0045-7825

A computationally affordable modeling of dynamic fracture phenomena is performed in this study by using strain injectiontechniques and Finite Elements with Embedded strong discontinuities (E-FEM). In the present research, classical strain localizationand strong discontinuity approaches are considered by injecting discontinuous strain and displacement modes in the finite elementformulation without an increase of the total number of degrees of freedom. Following the Continuum Strong DiscontinuityApproach (CSDA), stress?strain constitutive laws can be employed in the context of fracture phenomena and, therefore, themethodology remains applicable to a wide number of continuum mechanics models. The position and orientation of thedisplacement discontinuity is obtained through the solution of a crack propagation problem, i.e. the crack path field, based onthe distribution of localized strains. The combination of the above mentioned approaches is envisaged to avoid stress-locking anddirectional mesh bias phenomena.Dynamic simulations are performed increasing the loading rate up to the appearance of crack branching, and the variation interms of failure modes is investigated as well as the influence of the strain injection together with the crack path field algorithm.Objectivity of the presented methodology with respect to the spatial and temporal discretization is analyzed in terms of thedissipated energy during the fracture process. The dissipation at the onset of branching is studied for different loading rateconditions and is linked to the experimental maximum velocity observed before branching takes place.