DYNAMIC FRACTURE-TOUGHNESS MEASUREMENTS AND LOCAL APPROACH MODELING OF TITANIUM-ALLOYS

Two titanium alloys TA6V and TD5AC were tested. Tensile tests were per formed, under static and dynamic loadings, on cylindrical notched and fatigue precracked specimens. The visco-plastic constitutive equations of the alloy were found by fitting finite element computations with t he experimental results. The dynamic fracture toughness was obtained b y applying the convolution method of Bui and Maigre. Results for the T A6V alloy did not display significant variations of fracture toughness with loading rate, whereas for the TD5AC alloy an increase was measur ed. The critical void growth was found to be independent of the strain rate. Fair predictions of the fracture toughness under static as well as under dynamic conditions could be achieved by finite element compu tations using these experimental critical void growth values.