Micromechanical modeling of failure behavior of metallic materials

Abstrakti

Microstructural and micromechanical modeling is arising as a key material modeling technique providing numerical modeling capabilities with an improved description of critical material features and mechanisms. Material characteristics such as microstructural morphologies, individual phases and defects can be included explicitly in numerical models and their significance to the material properties and performance measures of interest quantified. Similarly, mechanisms dependent on microstructural scale mechanisms such as polycrystalline plasticity can be modeled accounting for such anisotropic phenomena, and as such, improved accuracy can be reached with respect to design critical mechanisms such as cleavage fracture and initiation of short fatigue cracks.
Micromechanical modeling deals with evaluating and modeling material failure relevant mechanisms at the scale of the material microstructure. Typical example is material damage with respect to ductile or brittle fracture, fatigue damage and crack initiation, or for example analysis of material wear which can be seen as a more intricate failure process where several mechanisms interact across multiple spatial scales. Current work addresses some typical failure mechanisms of metallic materials at the scale of the material microstructure. Case studies are discussed where micromechanical modeling is employed to assess material failure with different damage mechanical models and concepts. The basis in all is the description of material deformation by crystal plasticity constitutive models. Two treatments of damage are considered: direct coupling of the crystal plasticity model to a damage mechanical approach and a simpler methodology where a non-coupled evaluation of damage parameters is considered. The use cases consist of fracture, fatigue and wear problems from problems targeting both design of new materials, optimization of material solutions and improved design of products and components.