Study On Fatigue Damage Of Concrete Based On ICT Technique

Concrete bridges account for more than 90% of the total number of bridges in China.It is generally in a long-term overloading operation state,and there is a security risks of fatigue damage.It is the key of bridge management at present in China.This paper takes the concrete material as the breakthrough,based on the ICT technology to develop the concrete fatigue damage research,and the fatigue mechanism of concrete is explored.This paper combines concrete fatigue test,fracture theory,concrete constitutive theory,and numerical calculation theory to analyze the correlation between meso-structure and macro-fatigue performance of concrete.The research work and achievements are as follows:Firstly,the ICT technology was introduced into the concrete fatigue test to observe the internal fatigue crack propagation state.At the same time,the macroscopic parameters of the concrete fatigue process were acquired.The datas was compared with previous studies,and got well-matched results.At the same time,in-depth analysis of the results of the macro test was done,then summed up the law for the experimental data and the formation of S-N curve equations.Secondly,according to the image of the fatigue process of concrete obtained by ICT,the expansion state of fatigue cracks is analyzed,and the newly added porosity in the fatigue process is extracted as the microscopic parameter of the overall distribution of fatigue cracks.Combined the ICT images with fracture theory to analyze the fatigue failure mechanism of concrete.It is believed that the interface between aggregate and cement mortar is one of the most unfavorable areas,and is also the germination site of the initial microcracks,which will germinate and expand into a fatigue main crack.Thirdly,after verifying and analyzing the existing damage factor D in the concrete fatigue damage constitutive model use test datas,the ICT-related image analysis and statistical functions are used to quantitatively describe the overall distribution of concrete fatigue cracks.The damage factor D that can better reflect the overall distribution of the concrete fatigue cracks are defined.This definition can better show the development and evolution of fatigue damage caused by fatigue during compression fatigue of concrete from the overall crack distribution.Finally,the numerical simulation method of the concrete fatigue is deeply studied,The CDP model in ABAQUS is used to simulate the test conditions,which confirms the cumulative trend of fatigue damage effects.Combined ICT technology with related software,a 3D modeling method for concrete considering the initial defects is proposed.Combining ICT technology and image processing technology,a set of 2D concrete meso-model modeling method was proposed.After loading according to actual conditions,the simulation results were obtained and compared with the conventional homogeneous model and actual test results.Combining ICT technology with image processing technology,a 2D concrete meso-model modeling method was proposed.After loading according to actual conditions,the simulation results were obtained and compared with the conventional homogeneous model and actual test results.The results were basically consistent with the actual results,and the simulation effect was better than the conventional homogeneous model.In summary,this paper is based on the ICT technology to carry out the above-mentioned experimental research,theoretical derivation,and numerical simulation of fatigue damage of concrete.The results have great practical significance and economic value,for they will play a role in promoting the increasingly stringent concrete bridges management and maintenance work in China,at the field of basic theoretical.