On the validity of strain energy density criterion for mixed mode I/II fracture analysis of notched shape memory alloy components Academic Article uri icon

abstract

  • 2019 Elsevier Ltd This paper investigates the fracture behavior of notched polycrystalline shape memory alloy components utilizing the strain energy density (SED) approach and considering combined tensile/shear loading for the first time. The SED approach has been widely used to explore fracture paths and the onset of fracture in notched components made of conventional ductile metals (e.g., aluminum) as well as brittle and quasi-brittle materials, but its application to shape memory alloys has heretofore not been addressed. For a notched polycrystalline shape memory alloy component subjected to thermomechanical loading, the effects of different material parameters including maximum transformation strain, Young's modulus, and temperature on the SED distribution around notch tip and the fracture angle are explored and discussed. The validity of the theoretical formulations deployed for estimation of the transformation zones and strain fields are examined by comparing closed-form solutions with the results obtained from comparable finite element calculations. It is shown that the efficiency of the SED approach is limited as the ratio of the normalized maximum transformation strain to the normalized effective notch stress intensity factor exceeds a critical value; such conditions have not been previously reported for non-transforming metals. Finally, the effects of the notch tip radius on the fracture angle and SED distribution around the notch tip are evaluated.
  • © 2019 Elsevier Ltd This paper investigates the fracture behavior of notched polycrystalline shape memory alloy components utilizing the strain energy density (SED) approach and considering combined tensile/shear loading for the first time. The SED approach has been widely used to explore fracture paths and the onset of fracture in notched components made of conventional ductile metals (e.g., aluminum) as well as brittle and quasi-brittle materials, but its application to shape memory alloys has heretofore not been addressed. For a notched polycrystalline shape memory alloy component subjected to thermomechanical loading, the effects of different material parameters including maximum transformation strain, Young's modulus, and temperature on the SED distribution around notch tip and the fracture angle are explored and discussed. The validity of the theoretical formulations deployed for estimation of the transformation zones and strain fields are examined by comparing closed-form solutions with the results obtained from comparable finite element calculations. It is shown that the efficiency of the SED approach is limited as the ratio of the normalized maximum transformation strain to the normalized effective notch stress intensity factor exceeds a critical value; such conditions have not been previously reported for non-transforming metals. Finally, the effects of the notch tip radius on the fracture angle and SED distribution around the notch tip are evaluated.

published proceedings

  • ENGINEERING FRACTURE MECHANICS

author list (cited authors)

  • Mirsayar, M. M., & Hartl, D. J.

citation count

  • 9

complete list of authors

  • Mirsayar, MM||Hartl, DJ

publication date

  • June 2019