FRACTURE-MECHANICS AT INTERMEDIATE RATES OF LOADING - THE INFLUENCE OF THE ACCELERATION ON COMPACT TENSION TESTS

Compact Tension specimens were loaded at 1 and 7 m/s with two differen t accelerations imposed. Experimental photoelastic patterns recorded b y a high speed camera were compared with those simulated by dynamic el astic Finite Element (FE) analysis. The positive results of this compa rison validated the FE analysis. It is demonstrated that when the init ial acceleration of the specimen is low (using a damper in the loading device), static analysis can be applied for both testing speeds used. In high accelerations tests (without damper used), a transient dynami c stress state in the specimens is found, therefore a dynamic analysis should be used. Furthermore, in high acceleration tests a transient m ixed mode of loading at the crack tip occurs.