| Most of the recent interest in the thermomechanics of fracture has focused on high speed dynamic crack growth, where the high temperatures achieved can lead to thermal softening of the material. In contrast, during slow, stable crack propagation the heat generated has more time to diffuse away from the process zone and the resulting temperature field is not strong enough to significantly affect material properties such as flow stress and modulus of elasticity. In this research, our goal is to demonstrate that even for slow moving cracks, where heat conduction plays an important role, the measured temperature field can be used to obtain quantitative information about the energy required to drive the crack and a qualitative description of the distributed damage to the material.; The temperature field ahead of a stable, mode I, growing crack in a ductile material (302 stainless steel) is imaged using an infrared imaging system. The thermal images are analyzed to compute plastic dissipation and energy flux to the crack.; Fully coupled temperature-displacement finite element analysis are performed to model these experiments. The FEA assumes conditions of 2D, plane stress and isotropic elasto-plasticity. Crack propagation is modeled by node release based on measured crack length history.; By obtaining a good match between experimentally measured and simulated temperature fields, the formulation of the constitutive equations is verified and the ability to use infrared imaging to measure the temperature field associated with crack growth is validated. |
