Time Reliability Analysis Of Concrete Structures Under Fatigue

Concrete structure is widely used in engineering field, the utility model has the advantages of convenient use, low price, good durability, good seismic performance, easy adjustment and performance of environmental protection; because of the particularity of the concrete material, it also has some shortcomings, such as the self weight is too big, easy to produce cracks, maintenance period is too long, cold regions of long duration, underdeveloped areas has not been popular, we in the use process is to avoid these disadvantages, in order to ensure the safe and reliable structure.The fatigue load, repeated a character causes of cracks in concrete and the fatigue failure of concrete structure has also in mechanics, hydraulic concrete structure is no exception, and the fatigue load of hydraulic structures are often subjected to stress is high, the low cycle fatigue damage will occur.The process of low cycle fatigue failure is random, to analyze the random fatigue process is an innovation in this paper using the stochastic finite element method.The specific work is as follows:(1)By using ANSYS parametric design language APDL of senior Longkaikou gravity dam, three-dimensional finite element model is established, the formation of a cyclic process contains a complete simulation analysis of documents, and then performs the analysis file and initialize the probability design, build a probabilistic design analysis database.(2) Considering the more data need to extract the probability design method, simulation method to select mixed high computational efficiency (HSM)for reliability analysis, the method is based on response surface method based on Monte Carlo sampling calculation, therefore, can obtain the equation function display expression and reliability value.(3) Distribution of the finite element method of hydraulic concrete in compression and low cycle fatigue calculation method based on the Miner theory, the calculation method and the HSM method are combined to calculate fatigue life, law with cycle time and seismic load times reliability variation of damage, failure probability, at last, two methods are compared and some useful conclusions are obtained. (4) The statistical distribution of fatigue life and the fatigue cumulative damage verification, and the analysis of sensitivity and correlation, view leads to fatigue life and damage of discrete reasons, analysis results are consistent with the experiment.(5) The combination of hydraulic concrete strength attenuation model in the low-cycle fatigue and fatigue reliability analysis of residual strength degradation model, the introduction of stochastic finite element method analysis of the law of hydraulic concrete strength degradation and reliability variation.