Recent engineering design practice for materials and structures relies more and more on damage-tolerant criteria. Such a design approach is attained mainly by employing materials showing a certain level of fracture toughness. This work aims to explore a way to generate fracture toughness in materials that intrinsically shows no toughness at all, i.e. brittle materials. The key idea lies in the introduction of inelastically deformed sub-regions (e.g. circular inclusions) in the base material, which inevitably generate a residual stress field. To accomplish this purpose, the advanced Phase-Field method coupled with the eigenstrain theory is employed, respectively to simulate the crack propagation behavior and to introduce a residual stress field in a pre-notched sample. Information about crack propagation and displacement externally imposed is used to obtain the resistance curve (R-curve) for several configurations. One of the main findings of this research regards the possibility of originating fracture toughness in intrinsically brittle materials upon appropriate positioning of one inclusion - containing a certain amount of inelastic deformation – with respect to a notch tip. This result demonstrates that accurate design of residual stress is crucial to attaining unprecedented material or structure performance, and the method shown here represents a valid tool to exploit this advanced design capability.

Residual stress as a fracture toughening mechanism: A Phase-Field study on a brittle material

Salvati E.
2021-01-01

Abstract

Recent engineering design practice for materials and structures relies more and more on damage-tolerant criteria. Such a design approach is attained mainly by employing materials showing a certain level of fracture toughness. This work aims to explore a way to generate fracture toughness in materials that intrinsically shows no toughness at all, i.e. brittle materials. The key idea lies in the introduction of inelastically deformed sub-regions (e.g. circular inclusions) in the base material, which inevitably generate a residual stress field. To accomplish this purpose, the advanced Phase-Field method coupled with the eigenstrain theory is employed, respectively to simulate the crack propagation behavior and to introduce a residual stress field in a pre-notched sample. Information about crack propagation and displacement externally imposed is used to obtain the resistance curve (R-curve) for several configurations. One of the main findings of this research regards the possibility of originating fracture toughness in intrinsically brittle materials upon appropriate positioning of one inclusion - containing a certain amount of inelastic deformation – with respect to a notch tip. This result demonstrates that accurate design of residual stress is crucial to attaining unprecedented material or structure performance, and the method shown here represents a valid tool to exploit this advanced design capability.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11390/1207716
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 21
  • ???jsp.display-item.citation.isi??? ND
social impact