To understand the specific behaviors of coastal coral sand slope foundations,discrete element method(DEM)was employed to examine the effect of breakable particle corners on the performance of coral sand slope foundati...To understand the specific behaviors of coastal coral sand slope foundations,discrete element method(DEM)was employed to examine the effect of breakable particle corners on the performance of coral sand slope foundations under a strip footing,from macro to micro scales.The results demonstrate that the bearing characteristics of coral sand slope foundations can be successfully modeled by utilizing breakable corner particles in simulations.The dual effects of interlocking and breakage of corners well explained the specific shallower load transmission and narrower shear stress zones in breakable corner particle slopes.Additionally,the study revealed the significant influence of breakable corners on soil behaviors on slopes.Furthermore,progressive corner breakage within slip bands was successfully identified as the underling mechanism in determining the unique bearing characteristics and the distinct failure patterns of breakable corner particle slopes.This study provides a new perspective to clarify the behaviors of slope foundations composed of breakable corner particle materials.展开更多
In this work, a set of GTN （Gurson-Tvergaard-Needleman） parameters of the Alloy52M dissimilar metal welded joint （DMWJ） have been calibrated, and a micromechanical analysis of in-plane constraint effects on the lo...In this work, a set of GTN （Gurson-Tvergaard-Needleman） parameters of the Alloy52M dissimilar metal welded joint （DMWJ） have been calibrated, and a micromechanical analysis of in-plane constraint effects on the local fracture behavior of two cracks, which located in the weakest regions of the DMWJ, has been investigated by the local approach based on the GTN damage model. The results show that the partition of the material and the variation of the q2 parameter make the J-resistance curves obtained by numerical simulations close to the experimental values. The numerical J-resistance curves and crack growth paths are consistent with the experiment results, which show that the GTN damage model can incorporate the in-plane constraint effect. Furthermore, after the stress, strain and damage fields at the crack tip during the crack propagation process have been calculated, and the change of the J-resistance curves, crack growth paths and fracture mechanism with in-plane constraint have been analyzed.展开更多
In this research,the tensile properties'performance of compression moulded discontinuous randomized zalacca fibre/high-density polyethylene under critical fibre length was analysed by means of experimental method ...In this research,the tensile properties'performance of compression moulded discontinuous randomized zalacca fibre/high-density polyethylene under critical fibre length was analysed by means of experimental method and micromechanical models.These investigations were used to verify the tensile properties models toward the effect of fibre length and volume fraction on the composites.The experimental results showed that the tensile properties of composites had significantly increased due to the enhancement of fibre length.On the contrary,a decline in the tensile properties was observed with the increase of volume fraction.A comparison was made between the available experimental results and the performances of Tsai-Pagano,Christensen and Cox-Krechel models in their prediction of composites elastic modulus.The results showed that the consideration of fibre's elastic anisotropy in the Cox-Krenchel model had yielded a good prediction of the composites modulus,nevertheless the models could not accurately predict the composites modulus for fibre length study.展开更多
Up to now the analysis on aisnotropic effects of quasi-isotropic composites to material structures has not been found in literatures. In the present paper the strength model for triaxial woven materials proposed in ...Up to now the analysis on aisnotropic effects of quasi-isotropic composites to material structures has not been found in literatures. In the present paper the strength model for triaxial woven materials proposed in Part (I)[1]is applied to study the problems of an infintiely large plate of triaxial woven material containing either an either an elliptic hole or a crack. TO the elliptic hole problem the remote coritical loading as a function of the geometric parameters of woven materials is analysed and to the crack problem, the cracking orientation is examined. Finally the elasticity and strength models for a triaxial woven material proposed in Part (I)are verfied in terms of micromechanical analysis.展开更多
The surface texture of the pavement plays a very important role in driving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rub...The surface texture of the pavement plays a very important role in driving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rubber depends mainly on the pavement surface texture. In the present paper, the effect of micromechanical pavement surface morphology on rubber block friction was brought in by comparing the friction results for three different asphalt mix morphological surfaces, named stone mastic asphalt （SMA）, ultra-thin surfacing （UTS） and porous asphalt （PA）. The asphalt surface morphologies of these mixes were captured by using an X-ray tornographer, from which the resulting images micromechanical finite element （FE） meshes for SMA, UTS and PA pavements were developed by means of the SimpleWare software. In the FE model, the rubber and asphalt binder were modeled as viscoelastic （V-E） materials and the formulation was given in the large deformation frame- work. FE simulations were then carried out by using contact algorithm between rubber and the road surface. It was observed that the rubber friction inversely varies with the sliding speed and positively varies with the pressure for all the pavement morphological and stiffness conditions. Furthermore, it was observed that the highly porous pavement surface results in large dissipation of energy, hence, large rubber friction which shows that the mix characteristics of pavements have a simaificant effect on rubber friction.展开更多
基金Projects(51878103,52208370)supported by the National Natural Science Foundation of ChinaProject(cstc2020jcyjcxtt X0003)supported by the Innovation Group Science Foundation of the Natural Science Foundation of Chongqing,ChinaProject(2022CDJQY-012)supported by the Fundamental Research Funds for the Central Universities,China。
文摘To understand the specific behaviors of coastal coral sand slope foundations,discrete element method(DEM)was employed to examine the effect of breakable particle corners on the performance of coral sand slope foundations under a strip footing,from macro to micro scales.The results demonstrate that the bearing characteristics of coral sand slope foundations can be successfully modeled by utilizing breakable corner particles in simulations.The dual effects of interlocking and breakage of corners well explained the specific shallower load transmission and narrower shear stress zones in breakable corner particle slopes.Additionally,the study revealed the significant influence of breakable corners on soil behaviors on slopes.Furthermore,progressive corner breakage within slip bands was successfully identified as the underling mechanism in determining the unique bearing characteristics and the distinct failure patterns of breakable corner particle slopes.This study provides a new perspective to clarify the behaviors of slope foundations composed of breakable corner particle materials.
基金supported by the National Natural Science Foundation of China(Grant No.51605292)the Natural Science Foundation of Shanghai(Grant No.15ZR1429000)the Youth Foundation of Shanghai(Grant No.ZZslg15013)
文摘In this work, a set of GTN （Gurson-Tvergaard-Needleman） parameters of the Alloy52M dissimilar metal welded joint （DMWJ） have been calibrated, and a micromechanical analysis of in-plane constraint effects on the local fracture behavior of two cracks, which located in the weakest regions of the DMWJ, has been investigated by the local approach based on the GTN damage model. The results show that the partition of the material and the variation of the q2 parameter make the J-resistance curves obtained by numerical simulations close to the experimental values. The numerical J-resistance curves and crack growth paths are consistent with the experiment results, which show that the GTN damage model can incorporate the in-plane constraint effect. Furthermore, after the stress, strain and damage fields at the crack tip during the crack propagation process have been calculated, and the change of the J-resistance curves, crack growth paths and fracture mechanism with in-plane constraint have been analyzed.
文摘In this research,the tensile properties'performance of compression moulded discontinuous randomized zalacca fibre/high-density polyethylene under critical fibre length was analysed by means of experimental method and micromechanical models.These investigations were used to verify the tensile properties models toward the effect of fibre length and volume fraction on the composites.The experimental results showed that the tensile properties of composites had significantly increased due to the enhancement of fibre length.On the contrary,a decline in the tensile properties was observed with the increase of volume fraction.A comparison was made between the available experimental results and the performances of Tsai-Pagano,Christensen and Cox-Krechel models in their prediction of composites elastic modulus.The results showed that the consideration of fibre's elastic anisotropy in the Cox-Krenchel model had yielded a good prediction of the composites modulus,nevertheless the models could not accurately predict the composites modulus for fibre length study.
文摘Up to now the analysis on aisnotropic effects of quasi-isotropic composites to material structures has not been found in literatures. In the present paper the strength model for triaxial woven materials proposed in Part (I)[1]is applied to study the problems of an infintiely large plate of triaxial woven material containing either an either an elliptic hole or a crack. TO the elliptic hole problem the remote coritical loading as a function of the geometric parameters of woven materials is analysed and to the crack problem, the cracking orientation is examined. Finally the elasticity and strength models for a triaxial woven material proposed in Part (I)are verfied in terms of micromechanical analysis.
基金by the National Priorities Research Program (NPRP) award (NPRP No. 7-482-2-184: Thermo-mechanical Tire-Pavement Interaction: Computational Modeling and Field Measurements) from the Qatar National Research Fund (a member of the Qatar Foundation)
文摘The surface texture of the pavement plays a very important role in driving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rubber depends mainly on the pavement surface texture. In the present paper, the effect of micromechanical pavement surface morphology on rubber block friction was brought in by comparing the friction results for three different asphalt mix morphological surfaces, named stone mastic asphalt （SMA）, ultra-thin surfacing （UTS） and porous asphalt （PA）. The asphalt surface morphologies of these mixes were captured by using an X-ray tornographer, from which the resulting images micromechanical finite element （FE） meshes for SMA, UTS and PA pavements were developed by means of the SimpleWare software. In the FE model, the rubber and asphalt binder were modeled as viscoelastic （V-E） materials and the formulation was given in the large deformation frame- work. FE simulations were then carried out by using contact algorithm between rubber and the road surface. It was observed that the rubber friction inversely varies with the sliding speed and positively varies with the pressure for all the pavement morphological and stiffness conditions. Furthermore, it was observed that the highly porous pavement surface results in large dissipation of energy, hence, large rubber friction which shows that the mix characteristics of pavements have a simaificant effect on rubber friction.
