Thermomechanical properties of non-linear refractories

Thermomechanical fracture properties of self-flow refractory castables were derived and presented. The energy release rate for a double cantilever beam was modeled using the finite element method in the presence of a thermal gradient and compared to accepted solutions. The modulus of elasticity of refractory castables is reviewed and measured as a function of temperature by a novel technique, the impulse excitation method. An equation for the energy release rate of the wedge loaded specimen was found and compared to the compact tension, three point bend and double cantilever beam specimen. Energy release rates including the linear elastic energy release rate, critical energy release rate and work of fracture were measured isothermally at room temperature and 600°C, in a gradient from 600°C to room temperature and from room temperature to 600°C and along an isotherm in a thermal gradient. The energy release rates were compared and variations were explained due to composition and thermal gradient. Hasselman's thermal shock parameters were reviewed and converted to fracture mechanics energy release rate and work of fracture values. Thermal expansion was measured and used in conjunction with the energy release rate for crack initiation and work of fracture to calculate and compare non-thermal transport based thermal shock parameters.