A SINGLE LEG BENDING TEST FOR INTERFACIAL FRACTURE-TOUGHNESS DETERMINATION

A single leg bending test is described and its suitability for interfa cial fracture toughness testing is evaluated. The test specimen consis ts of a beam-type geometry comprised of two materials, one 'top' and o ne 'bottom,' with a split at one end along the bimaterial interface. A portion of the bottom material in the cracked section of the beam is removed and the geometry is loaded in three-point bending. Thus, the r eaction force of the support at the cracked end is transmitted only in to the material comprising the top portion of the beam. The test is an alyzed by a crack tip element analysis and the resulting expressions f or energy release rate and mode mixity are verified by comparison with finite element results. It is shown that, by varying the thicknesses of the two materials, the single leg bending test can be used to deter mine the fracture toughness of most bimaterial interfaces over a reaso nably wide range of mode mixities.