Parametric optimization of constitutive and failure model to numerically simulate the dynamic fracture response of AA7475-T7351 under extreme thermomechanical loading

Abstract

The ability to regulate a material’s fracture toughness is critical for achieving ductile fracture arrest design for the transportation and defiance industry. The present study utilized the data of split Hopkinson tensile bar experiments and uniaxial quasi-static tensile experiments to evaluate the parameters of Johnson-Cook constitutive and failure models for AA7475-T7351. Estimated constitutive and fracture parameters are further optimized using programming and numerical simulation for better predictability. The dynamic three-point bend experiments were performed to assess the fracture toughness of AA7475-T7351 using a modified Hopkinson pressure bar under different temperatures and strain rates. The findings indicate that the fracture behaviour is affected by material orientations, loading rates and temperatures. The 3D-digital image correlation (DIC) technique was used to get the full field displacement data of the three-point bend (TPB) and tensile specimens. The experimental findings of the TPB specimen from DIC post-processing were further compared with the numerical outcome in terms of load point displacement (LPD), crack mouth opening displacement (CMOD) and crack mouth opening displacement contour. A comprehensive error analysis is used to correlate the experimental and numerical results. The numerical and experimental findings are reasonably in agreement with one another. The determined constants for the JC Constitutive and Failure models are applicable for strain rate approximately 5000 s−1 and temperatures ranging from −200 to 250 °C.