Damage, Material Instabilities, and Failure

Abstract

AbstractThis chapter begins with an overview of damage mechanics. Isotropic and anisotropic models are described, as well as the coupling to plasticity, including the algorithmic treatment. Next, the implications of strain softening, which starts at a certain level of damage accumulation, are discussed as regards important notions such as material stability and ellipticity. The consequences of loss of ellipticity in terms of grid sensitivity of computations are illustrated for static and for dynamic instabilities. Next, the important role of cohesive‐zone models is highlighted, both in its original (discrete) format, a derived smeared format and as an embedded discontinuum description. To avoid loss of ellipticity, the introduction of higher‐order continua is necessary. Various higher‐order continua incorporating damage or coupled damage‐plasticity models are discussed, including aspects of numerical implementation. Finally, the numerical implementation of cohesive‐zone models in a discrete format is considered, where attention is given to conventional interface elements as well as to approaches that exploit the partition‐of‐unity property of finite element shape functions.