Verification of fracture parameter for uncoupled thermoinelasticity

Abstract

The path domain independent integral, S, characterizes fracture within a thermoinelastic material response region. A limited experimental program and associated computational investigation verify that S characterizes fracture for uncoupled thermoplasticity. Thermomechanical fracture resistance experiments on 2024 aluminum demonstrate that S equals the crack driving force. The fracture resistance experiments consider two specimen geometries and two specimen thicknesses. The experiments demonstrate that a 1.4°C/mm thermal gradient across the specimen width significantly reduces the applied tension necessary to initiate crack extension. Finite element computations model eight selected fracture toughness experiments showing that the S integral characterizes fracture under thermomechanical loading. The S integrals computed from the finite element analyses match those estimated from the experimental force displacement trace for the isothermal cases, thereby verifying the S calculation. Furthermore, the S integrals calculated for the thermomechanical loading cases agree with the values from the isothermal cases suggesting that S characterizes incipient fracture.