Ductile damage evolution in high purity copper taylor impact test

Abstract

Abstract.Recently, the continuum damage mechanics model proposed by Bonora (Eng. Fract. Mech. 58, 1997) has been updated to account for stress triaxiality effect on model parameters, (Bonora et al., AIP Conf. Proc. 1195, 2009. This model enhancement allows to predict ductile damage initiation under varying stress states (uniaxial stress, uniaxial strain, and complex load paths) and dynamic loading conditions. In this work, the model has been used to investigate ductile damage developments in Taylor anvil and symmetric Taylor impact (rod-on-rod) configuration. Although the two configurations are equivalent for right scaled impact velocities, experimental evidences show that when ductile damage occurs in rod-on-rod not necessarily also develops in Taylor anvil impact. It has been found that, in the two impact configurations, the stress triaxiality builds up differently with plastic strain leading to different conditions for ductile damage initiation. Taylor impact tests have been designed and performed with the gas-gun facility at the University of Cassino. Damage investigation results obtained on recovered samples have been compared with rod-on-rod data reported in the literature and used to validate the proposed model predictions.

The effect of subcritical ductile crack growth on cleavage fracture probability in the transition regime using continuum damage mechanics simulation

“…Geometry transferability of Bonora damage model (BDM) parameters has been verified for several classes of metals, geometries and type of loading [34][35][36][37][38]. In the case of cracked components, the model successfully predicted constraint effect on crack resistance in ferritic steel A533B [34] and pipe bi-metallic girth weld [39].…”

Stress triaxiality effect on void nucleation in ductile metals

“…In Figure , the contour plots of the damage at the interface and the equivalent plastic strain at the onset particle separation for T σ = 1/3 and 6 are given. This latter value, although apparently extreme and out of practical application, is typical for plate impact experiments where material may fail by spall fracture . Under uniaxial tensile loading, particle debonding occurs approximately at 0° (axial direction).…”

Strain capacity assessment of API X65 steel using damage mechanics

“…At failure, for D=D cr , assuming that the strain threshold for damage initiation is pressure independent -which is reasonable at relatively low stress triaxiality while it is not true in general [16,24,25] -the following expression can be obtained,…”

“…Bonora [14] proposed a damage model formulation for describing ductile damage evolution in different classes of metals and alloys. The model was successfully used to predict ductile rupture under different loading conditions and material microstructural states [15,16]. One of the key feature of this model formulation is the capability to account for stress triaxiality effects on material ductility [17].…”