A finite thickness band method for ductile fracture analysis

A.E. HUESPE; A. NEEDLEMAN,; J. OLIVER,; P. J. SANCHEZ

INTERNATIONAL JOURNAL OF PLASTICITY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2009 vol. 25 p. 2349 - 2365

0749-6419

We present a finite element method with a finite thickness embeddedweak discontinuity to analyze ductile fracture problems. Theformulation is restricted to small geometry changes. The materialresponse is characterized by a constitutive relation for a progressivelycavitating elastic?plastic solid. As voids nucleate, grow andcoalesce, the stiffness of the material degrades. An embedded weakdiscontinuity is introduced when the condition for loss of ellipticityis met. The resulting localized deformation band is given a specifiedthickness which introduces a length scale thus providing aregularization of the post-localization response. Also since the constitutiverelation for a progressively cavitation solid is used insidethe band in the post-localization regime, the traction-opening relationacross the band depends on the stress triaxiality. The methodologyis illustrated through several example problems includingmode I crack growth and localization and failure in notched bars.Various finite element meshes and values of the thickness of thelocalization band are used in the calculations to illustrate the convergencewith mesh refinement and the dependence on the valuechosen for the localization band thickness