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Unpredicted failure in metals is of growing scientific interest, as it is observed for
a number of metals that are becoming increasingly popular for sheet metal
applications (e.g. advanced high strength steels, aluminum 6xxx series). These
failures are believed to be triggered by ductile damage evolution. Numerical
damage evolution models are being developed to precisely predict “safe”
deformation limits in forming and service. However, these models require
accurate input of damage evolution laws of these types of metals. Many damage
characterization methods are available for this purpose, which were initially
analyzed and classified in the pioneering work of Lemaitre [1]. Indentation-based
damage quantification, which couples the degradation of either hardness or elastic
modulus to the evolution of damage, was regarded as the most promising method
[1] and, ever since, is used frequently in literature (see, e.g., Refs. [1]-[5]) and in
industry. However, in previous work we showed that this approach has significant
intrinsic flaws, for both hardness- and modulus-based damage quantification [6].