A new spherical triangular finite element based on shallow shell formulation is developed in this paper. The element has six degrees of freedom at each comer node, five of which are the essential external degrees of f...A new spherical triangular finite element based on shallow shell formulation is developed in this paper. The element has six degrees of freedom at each comer node, five of which are the essential external degrees of freedom and the additional sixth is associated with the in-plane shell rotation. The displacement fields of the element satisfy the exact requirement of rigid body modes of motion. The element is based on independent strain assumption insofar as it is allowed by the compatibility equations. The element developed herein is first validated by applying it to the analysis of a benchmark problem involving a standard spherical shell with simply supported edges. The results of the analysis showed that reasonably accurate results were obtained even when modeling the shells using fewer elements compared to other shell element types. The element is then used in a finite element model to analyze polygon shaped spherical roof structures. The distribution of the various components of deflection and stress is obtained. Furthermore, the effect of introducing circular arched beams as stiffeners spanning the two diagonally opposite end comers is investigated. It is found that the stiffeners reduced the deflections and the stresses in the roof structure by considerable value.展开更多
Despite advancements in computational resources,the discrete element method(DEM)still requires considerable computational time to solve detailed problems,especially when it comes to the large-scale models.In addition ...Despite advancements in computational resources,the discrete element method(DEM)still requires considerable computational time to solve detailed problems,especially when it comes to the large-scale models.In addition to the geometry scale of the problem,the particle shape has a dramatic effect on the computational cost of DEM.Therefore,many studies have been performed with simplified spherical particles or clumps.Particle scaling is an approach to increase the particle size to reduce the number of particles in the DEM.Although several particle scaling methods have been introduced,there are still some disagreements regarding their applicability to certain aspects of problems.In this study,the effect of particle scalping on the shear behavior of granular material is explored.Real granular particles were scanned and imported as polygonal particles in the direct shear test.The effect of particle size distri-bution,particle angularity,and the amount of scalping were investigated.The results show that particle scalping can simulate the correct shear behavior of the model with significant improvement in computational time.Also,the accuracy of the scalping method depends on the particle angularity and particle size range.展开更多
文摘A new spherical triangular finite element based on shallow shell formulation is developed in this paper. The element has six degrees of freedom at each comer node, five of which are the essential external degrees of freedom and the additional sixth is associated with the in-plane shell rotation. The displacement fields of the element satisfy the exact requirement of rigid body modes of motion. The element is based on independent strain assumption insofar as it is allowed by the compatibility equations. The element developed herein is first validated by applying it to the analysis of a benchmark problem involving a standard spherical shell with simply supported edges. The results of the analysis showed that reasonably accurate results were obtained even when modeling the shells using fewer elements compared to other shell element types. The element is then used in a finite element model to analyze polygon shaped spherical roof structures. The distribution of the various components of deflection and stress is obtained. Furthermore, the effect of introducing circular arched beams as stiffeners spanning the two diagonally opposite end comers is investigated. It is found that the stiffeners reduced the deflections and the stresses in the roof structure by considerable value.
文摘Despite advancements in computational resources,the discrete element method(DEM)still requires considerable computational time to solve detailed problems,especially when it comes to the large-scale models.In addition to the geometry scale of the problem,the particle shape has a dramatic effect on the computational cost of DEM.Therefore,many studies have been performed with simplified spherical particles or clumps.Particle scaling is an approach to increase the particle size to reduce the number of particles in the DEM.Although several particle scaling methods have been introduced,there are still some disagreements regarding their applicability to certain aspects of problems.In this study,the effect of particle scalping on the shear behavior of granular material is explored.Real granular particles were scanned and imported as polygonal particles in the direct shear test.The effect of particle size distri-bution,particle angularity,and the amount of scalping were investigated.The results show that particle scalping can simulate the correct shear behavior of the model with significant improvement in computational time.Also,the accuracy of the scalping method depends on the particle angularity and particle size range.
