Papers by Author: Peng Cao

Abstract: To analyze the dynamic response of the pavement structure under moving vehicle loading is always a hot point in pavement engineering. In this paper, the moving vehicle has been simplified as spring-dashpot components and the pavement structure has also been discrete using three-dimension finite element model. Based on Newton iteration and central difference integration algorithm, the static and dynamic coupling reactions between pavement structure and vehicle have also been considered using finite element platform ABAQUS. The numerical results and analytic results can fit very well in static analysis, meanwhile the numerical results and experiment results can fit very well in dynamic analysis. Based on preceding verified numerical model, a few interesting phenomenon have been discovered. The pavement dynamic vertical displacement in upper layer is much higher than the situation in static analysis, because the vertical displacement is superimposed during the dynamic response analysis. Furthermore the vertical fluctuation of the vehicle's bar center exists even the vehicle moving in the initial even pavement, and the inertial forces is the most important reason to induce this behavior. In the last, this paper has proposed a more accurate, fast and concrete evidence to explain the reason that the dynamic response has obvious relationship with the diseases in pavement layer.

Abstract: In order to analyze the premature damage of dowel bar system in jointed concrete pavement, the eXtended finite element method (short for XFEM) coupled with submodeling method were employed to simulate the fracture process of concrete around the dowel bar under loading. This coupling method is based on 3-D finite element analysis for the whole concrete pavement structure. The initialization and evolution of the cracks on the concrete had been monitored in model simulation. The results demonstrate that the XFEM coupled with submodeling method is an efficient and accurate method to calculate the ultimate bearing capacity of dowel bar. Furthermore, the critical axle load could be back-calculated based on the former analyzing results. This study is expected to provide a valuable numerical analysis method to simulate the fracture process in stresses concentration region of the concrete structure.

Abstract: The degradation of concrete structures due to steel reinforcement corrosion is a serious problem for durability and serviceability. Cracking behavior due to reinforcement corrosion is evaluated experimentally and analytically in this paper. In the experiments, in which corrosion was induced electronically, the structure proportion of corrosion product was analyzed. In the analysis, a micromechanical cracking mechanical analytic model, which considered the coupling effects of corrosion product and concrete protective layer was established. The initial cracks and crack growth process of smeared cracks in cover concrete were simulated and explored for the deterioration process of concrete structures due to corrosion expansion. It is indicated that the numerically predicted crack mode agrees well with the experimental results.

Abstract: In order to study influence of different factors on interlayer shear strength of fiber seal, an orthogonal experiment about four factors, respectively, test temperature, fiber content, asphalt content and gravel coverage, and three levels are developed with bevel shear test. The influence rules are evaluated by range analysis method. The result demonstrated that fiber content is the most correlative influencing factor. Thus provides a basis for the selection of material and performance of the fiber seal.

Abstract: Using visco-elastoplastic-plastic finite element method, the resistant ability to rutting occurring in Heilongjiang province express way has been analyzed. Base on the numerical results, it has been found that the location of rutting occurring mainly existed in middle course, So some modified measurement of middle course to enhance the resistant rutting ability has been proposed. At the same time, A new user Subroutine, which is named dload of ABAQUS, has been employed to simulate the moving vehicle load ,this article has proposed a new method to predict rutting behavior .

Abstract: The saturated and unsaturated soil were widely studied by many researchers nowadays. With the development of calculation mechanics and computer, the discrete element method (DEM), as a powerful technique, has been implemented in saturated soil mechanics. This paper review the development of DEM and its application in saturated soil research. Meanwhile, it also prospect the application of DEM in unsaturated soil research. Besides, it also raised some problems that might be met in the real practice and it also tried to put forward some reasonable methods to solve these problems. In the end, this paper put forward a new DEM contact model based on the surface energy to analysis unsaturated soil.

Abstract: As a quick, accurate and efficient inspecting equipment, the Portable Falling Weight Deflectometer (PFWD) is widely used in subgrade modulus evaluation in the foreign countries. However, most analysis methods used in the modulus back calculation of PFWD is based on the classical Boussinesq solution or empirical formulas, which could hardly reflect the resilient of subgrade accurately. In this paper, the elastic half-space theory is introduced into the analysis of modulus back calculation, and with the integral transform and the numerical analysis, this paper provides an approximate method to evaluate the elastic modulus of subgrade.

Abstract: Based on extended finite element coupled with field variable method, fatigue damage numerical test of three point-bending beam with initial notch has been made to predict crack propagation path, numerical results showed : under the fatigue loading with 200Hz, and amplitude is 20KN, length of crack expanding was the biggest and crack grew as some angles with the initial crack during the first loading, crack propagated parallel to the initial angle during the other loading cycle. These results can fit the experiment very well. Using Fortran, A new user subroutine named USDFILD (User subroutine to redefine field variables at a material point) was also provided on the platform of ABAQUS, which can modal the change of physic material with time. This user subroutine can also import fatigue characterize of material into the model.