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Yi Xu

Bio: Yi Xu is an academic researcher. The author has contributed to research in topics: Data pre-processing & Artificial intelligence. The author has an hindex of 1, co-authored 2 publications receiving 4 citations.

Papers
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TL;DR: In this paper , the authors investigated the mechanical response of asphalt surfaces under moving traffic loads using the three-dimensional (3D) discrete element method (DEM) and established a discrete element model for asphalt surface based on the random generation algorithm of irregular particles.
Abstract: This paper investigates the mechanical response of asphalt surfaces under moving traffic loads using the three-dimensional (3D) discrete element method (DEM). As an example of a semirigid base asphalt pavement, a discrete element model for asphalt surface was established based on the random generation algorithm of irregular particles in Python language and DEM. The model considered the temperature gradient and fatigue damage to simulate the permanent deformations, shear stresses, and strains in asphalt surfaces under different working conditions (e.g., different temperatures and numbers of repeated loads). Part of the simulation results was verified by performing a full-scale accelerated loading test (ALT). Results show that the 3D discrete element model embedded with temperature gradient and fatigue damage could be used to predict the mechanical response of asphalt surfaces under repeated loads. As the temperature increased, the mechanical response of asphalt surfaces increased. The middle surface was the main area of shear stresses in semirigid base asphalt pavements. Due to fatigue damage, the stresses and strains in asphalt surfaces increased with the number of repeated loads.

4 citations

Journal ArticleDOI
Bingyu Sun, Yi Xu, Shuhang Xie, Dong Xu, Yupu Liang 
TL;DR: A processing method including data preprocessing, feature extraction, feature selection, flow type classification and flow field parameters estimation, is proposed based on the data of the pressure sensors in an artificial lateral line.

Cited by
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TL;DR: In this paper , a three-dimensional meso-structure discrete element model of asphalt pavement was generated with the FISH programming language and its mesomechanical response under vehicle load was analyzed.
Abstract: Numerical simulation is an effective way to study the mechanical response of asphalt pavement, which is very important for the pavement structural design. In this study, a three-dimensional meso-structure discrete element model of asphalt pavement was generated with the FISH programming language and its meso-mechanical response under vehicle load was analyzed. The contact forces within the asphalt pavement, in asphalt mastic, in coarse aggregates and between asphalt mastic and coarse aggregates were studied. The results of the study show that the contact forces within the asphalt mixture are highly uneven. The number of contact points in coarse aggregates account only for about 10% of all contact points while the sum of the contact forces in coarse aggregates contributes to over 50% of all contact forces. This demonstrates that the coarse aggregates bear most of the vehicle load. The average normal contact force in coarse aggregates is about 5 N and the average tangential contact force in coarse aggregates is about 2 N. The modeling results provide a quantitative understanding of the distribution of loading in asphalt pavement.

1 citations

Journal ArticleDOI
TL;DR: Based on thermal-mechanical coupling simulation analysis and physical engineering tracking observation, the mechanical behavior and response of a continuously reinforced concrete and asphalt concrete composite pavement layer were analyzed, and the causes of cracking on the surface and bottom of the asphalt layer were revealed as discussed by the authors .
Abstract: Based on thermal–mechanical coupling simulation analysis and physical engineering tracking observation, the mechanical behavior and response of a continuously reinforced concrete and asphalt concrete (CRC + AC) composite pavement layer were analyzed, and the causes of cracking on the surface and bottom of the asphalt layer were revealed. Studies have shown that under normal driving conditions, the AC layer, which is usually in the position of the wheel load gap and wheel load side, more easily generates a longitudinal “corresponding crack”. Compared to normal driving, longitudinal cracks are generated more easily inside of the curve, and transverse cracks occur more easily on poor stadia curves. When the AC layer thickness is less than 8 cm, the AC layer is more prone to bottom-up cracking, and it is more prone to top-down cracking when it is more than 8 cm thick. Comprehensively considering the tensile stress, shear stress, and the thickness of the AC layer, it is recommended that the suitable thickness range of the AC layer is 8 cm~14 cm. The calculated results show good agreement with the physical engineering investigation. The research results can provide a theoretical and scientific basis for cracking control and the rational design of a CRC + AC composite pavement layer.

1 citations

Journal ArticleDOI
TL;DR: In this article , the authors analyzed the dynamic responses of asphalt pavement in dry and saturated conditions under full-scale accelerated loading and found that the increase in vehicle load significantly increased the magnitudes of stress, strain, and pore water pressure.
Abstract: Asphalt pavement presents diverse dynamic responses to vehicle loading in dry and saturated conditions, which can be systematically explored by numerical simulation. Building a numerical model based on the actual conditions of asphalt pavement is necessary, and relevant field tests should be subsequently conducted to monitor dynamic responses to calibrate and validate the numerical model. On the basis of strictly controlling the paths of vehicle wheels during field tests, this study numerically analyzed the dynamic responses of asphalt pavement in dry and saturated conditions under full-scale accelerated loading. The trends of the modeling results were consistent with those of field measurements. The increase in vehicle load significantly increased the magnitudes of stress, strain, and pore water pressure, while vehicle speed showed an obvious impact on pore water pressure. The dynamic responses decreased with pavement depths. Water made the dynamic responses more complex, and pore water pressure significantly decreased with depth within the upper layer of saturated asphalt pavement. Transverse distributions of indicators presented obvious compressive states in the regions in direct contact with vehicle wheels, while tensile states were found in the range of the middle vehicle axle. The numerical results provided a basis for field measurements in future studies, especially for the exploration of factors of temperature and layer depth.

1 citations

Journal ArticleDOI
TL;DR: In this paper , the authors used 3D discrete element models to predict the mechanical response of crumb rubber-modified (CRM) asphalt pavements under traffic loads using three-dimensional (3D) discrete element method (DEM).
Abstract: This study aims to predict the mechanical response of crumb rubber-modified (CRM) asphalt pavements under traffic loads using three-dimensional (3D) discrete element method (DEM). First, irregular-shaped aggregates were generated in Python language, and discrete element models of six different asphalt layers, which considered the temperature gradient and fatigue damage, were established using 3D DEM. Then, model parameters were obtained through the uniaxial creep test for asphalt mastics at different temperatures. The fatigue damage was implemented by introducing a damage factor into the Burgers model. Finally, three mechanical response parameters (namely, permanent deformation, shear stress and transverse strain) of the six asphalt layers under traffic loads were analysed and compared. Results show that the mechanical response of CRM asphalt layers under traffic loads is significantly influenced by number of repeated loads, temperature, and asphalt layer materials. The shear stress and transverse strain at the wheel centre vary along the depth of asphalt layers, and the middle layer is the principal area of shear stresses in asphalt pavements.

1 citations