Research On Nonlinear Mechanical Behavior Of Refractory Based On Microscopic Damage Mechanic

Refractory is an integral part of the high-temperature industrial buttress material and iswidely used in modern in industries. The refractory lining is subjected to strongthermomechanical loads due to the temperature gradient through the thickness and thetemperature cycles of the process. The resulting damage of the refractory is very important forthe prediction of service life duration of the refractorized structure. Traditional method was tomake phenomenological study from a macro-scale. But this method ignored the complex internalstructure of the material so that difficult to reveal the damage mechanism. Actually themacroscopic damage behaviour of refractory is the result of the microstructure damageaccumulation and evolution，but Macro-mechanical analysis is difficult to satisfy the mechanicalanalysis requirements. Based on this issue，Main works and achievements of the thesis are asfollows：（1）Based on the micro-damage mechanism of refractory under uniaxial compression, it isfirstly set up to analyze Micro-damage mechanism of the refractory. Then, a damage functionabout the external load based on the elastic modulus of the damage phase is constructed tocharacterize the micro-damage evolution. The thesis is to get a quantitative relationship betweenthe microstructure and macro effective elastic modulus by using the generalized self-consistentmodel. After that, a stress-strain curve is simulated to describe the nonlinear mechanicalbehavior of the refractory.（2）According to the material macroscopic damage mechanism, this thesis presented aresearch method which the starting point and end point of material damage is determined by thelow load stress strain curve. This method takes full account of the general evolution of materialmacroscopic deformation, has general applicability of refractory damage critical condition.（3）The thesis is to get a quantitative relationship between the microstructure and macroeffective elastic modulus by using the generalized self-consistent model. Then, a stress-straincurve is simulated to describe the nonlinear mechanical behavior of the refractory.（4）Numerical simulation of damage evolution of MgO-C refractory under compression ortension was compared with experimental data and provides good agreement between the modeland experiment.The proposed method is that by a quantitative relationship between the microstructure andexternal load，and to get a quantitative relationship between the microstructure and macroeffective elastic modulus by using the generalized self-consistent model, provides a new idea.