Fracture testing and finite element modeling of pure titanium

This paper presents the results of fracture experiments and corresponding finite element analyses (FEA) of pure titanium. This investigation was motivated by the desire to develop a J-R testing protocol and numerical procedures that are applicable to a titanium/titanium boride layered functionally graded material. Tensile tests and a two-dimensional axisymmetric finite element model were used to determine the plasticity data for the titanium. Crack growth experiments were conducted in three-point bending using single edge notched bend specimens. Three-dimensional FEA of crack growth initiation and two-dimensional FEA with automatic crack propagation were performed. Two crack propagation conditions based on experimental data were used: (a) crack length versus load-line displacement and (b) crack length versus crack mouth opening displacement. The subsequent predictions of the non-linear finite element models are in reasonable agreement with the measured value of J at initiation and with the rising J-R data during crack propagation.