A Method for Seeking the Domain of Chaboche Model of Cement Concrete Fatigue Damage under High Stress Ratio

In order to determine the domains of Chaboche model of cement concrete fatigue damage under high stress ratios, first, the probability densities of general monotonic random variables including cement concrete fatigue life are deduced. And then, the probability density of Chaboche fatigue damage model is deduced. By virtue of laboratory fatigue test results, the fatigue damage probability density functions of Chaboche model can be obtained, considering different stress ratios. Substituting load cycles into the functions, the cement concrete fatigue reliabilities based on Chaboche model can be acquired through integral operation. Finally, on the basis of cement concrete fatigue reliability analysis, the critical values of load cycle of Chaboche model under different high stress ratios can be made certain and the model's domains corresponding to these stress ratios can be obtained. The obtained results also show that under the same stress ratio, with the increase in the load cycle, the fatigue reliability declines gradually from almost 100% to 0%. No matter under any stress ratio, in the initial stage of load action, there is always a relatively stable phase for fatigue reliability. With the increase in the stress ratio, the phase diminishes gradually and the load cycle corresponding to reliability of 0% also decreases. In descent phase of reliability, the higher stress ratio is, the lower cement concrete reliability is for the same load cycle.