Steel wire wound reinforced flexible pipe in this study mainly consists of multiple anisotropic steel wire wound reinforcement layers and multiple isotropic rubber *** on 3D anisotropic elastic theory,the analytic sol...
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Steel wire wound reinforced flexible pipe in this study mainly consists of multiple anisotropic steel wire wound reinforcement layers and multiple isotropic rubber *** on 3D anisotropic elastic theory,the analytic solutions of stresses and elastic deformations of steel wire wound reinforced rubber flexible pipe under internal pressure are *** the adjacent reinforcement layers with wound angle have different radii,the single reinforcement layer shows the effect of tensile-shear ***,the static loading test results of steel wire wound reinforced rubber flexible pipe under internal pressure are basically coincided with the calculated values by present method.
This paper presents a new approach which possesses the semi-analytical feature of scaled boundary finite element method and the exact geometry feature of isogeometric analysis. NURBS basis functions are employed to co...
This paper presents a new approach which possesses the semi-analytical feature of scaled boundary finite element method and the exact geometry feature of isogeometric analysis. NURBS basis functions are employed to construct an exact boundary geometry. The domain boundary is discretized by NURBS curves for the 2D case, and NURBS surfaces for the 3D case. Especially the closed-form NURBS curves or surfaces are needed if there are no side-faces. The strategy of using finite elements on domain boundary with NURBS shape functions for approximation of both boundary geometry and displacements arises from the sense of isoparametric concept. With h-,p-,k- refinement strategy implemented, the geometry is refined with maintaining exact geometry at all levels, so the geometry is the same exact represented as the initial geometry imported from CAD system without the necessity of subsequent communication with a CAD system. Additionally, numerical example exhibits that flexible continuity within the NURBS patch rather than traditional shape functions improves continuity and accuracy of derivative stress and strain field across not only boundary elements but also domain elements, as the results of the combination of the intrinsic analytical property along radial direction and the higher continuity property of NURBS basis, i.e. it's more powerful in accuracy of solution and less DOF-consuming than either traditional finite element method or scaled boundary finite element method.
For efficient and accurate modelling of arch dam-reservoir-foundation system a coupled Finite Element method (FEM) and Scaled Boundary Finite Element method (SBFEM) is developed. Both the dam-foundation interaction an...
For efficient and accurate modelling of arch dam-reservoir-foundation system a coupled Finite Element method (FEM) and Scaled Boundary Finite Element method (SBFEM) is developed. Both the dam-foundation interaction and the dam-reservoir interaction including the effect of reservoir boundary absorption are taken into account. The arch dam is modelled by FEM, while the reservoir domain and the unbounded foundation are modelled by SBFEM. In order to make comparison with the results available in the literature, the Morrow Point arch dam is selected for numerical analysis. The analyses are carried out in the frequency domain, and then the time-domain response of the dam-reservoir-foundation system is obtained by Inverse Fourier Transform.
Based on the scaled boundary finite element method (SBFEM), a procedure is developed for evaluation of hydrodynamic pressure acting on arch/gravity dam face. The effect of water compressibility and the absorption of r...
Based on the scaled boundary finite element method (SBFEM), a procedure is developed for evaluation of hydrodynamic pressure acting on arch/gravity dam face. The effect of water compressibility and the absorption of reservoir bottom and sides are taken into consideration. Various factors that affect the earthquake induced hydrodynamic pressure are examined. Emphasis is placed on the influence of reservoir geometry on the magnitude and distribution of hydrodynamic pressure on arch/gravity dam face. Numerical examples demonstrate that SBFEM is a powerful numerical method dealing with hydrodynamic problems. It is computationally quite economical. The effects of water compressibility, reservoir boundary absorption as well as reservoir geometry can be considered with relative ease. Results also show that reservoir geometry affects the amplitude and distribution of hydrodynamic pressure acting on arch/gravity dam face considerably.
The J integral and the stress intensity factor (SIF) K are both important research objects of fracture mechanics, and are often employed to establish criteria for crackpropagation. The relationship between them has al...
The J integral and the stress intensity factor (SIF) K are both important research objects of fracture mechanics, and are often employed to establish criteria for crackpropagation. The relationship between them has always been a research hotspot. In this paper, the SIF can be obtained conveniently by the scaled boundary finite element method (SBFEM) due to the fact that analytical solution can be obtained along the radial direction for stress singularity problems. The J integral can be solved analytically using the formulae between J and K for mixed mode crack with arbitrary inclination in elastic materials. Moreover, the J integral values obtained by this method are more accurate and convenient than by its definition. Factors that affect the accuracy of SIF and J integral, such as the distance between the crack and outer boundary, size of the discretized elements and partition of the domain into super-elements, are examined.
Fibre-reinforced polymer (FRP) anchors made from rolled or bundled fibres, which are known as FRP anchors amongst other names, are an emerging form of anchorage for application to externally bonded FRP strengthening s...
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Fibre-reinforced polymer (FRP) anchors made from rolled or bundled fibres, which are known as FRP anchors amongst other names, are an emerging form of anchorage for application to externally bonded FRP strengthening systems. Little is however known of the fundamental behaviour of these anchors. This paper in turn reports the results of experiments on FRP anchors under pure tension (pullout) loading. A detailed description of the anchor construction procedure is firstly presented followed by anchor tensile strength test results. Pullout test results of FRP anchors embedded into uncracked concrete blocks are then reported with particular attention focused on the failure mechanisms, failure loads, bond strength and load- displacement and load-strain responses for varying anchor hole diameter, embedment depth and anchor fibre content. Finally, a large test data base is assembled from the results of the present study as well as two other studies found in the open literature. Relationships between the pullout load to the anchor diameter, embedment depth and concrete strength are identified while the effects of different methods of anchor construction are also discussed.
Computation electromagnetic is an important research field of electromagnetic fields and microwave technology subjects. In this paper, the scaled boundary finite element method (SBFEM) is extended to solve one type of...
Computation electromagnetic is an important research field of electromagnetic fields and microwave technology subjects. In this paper, the scaled boundary finite element method (SBFEM) is extended to solve one type of electromagnetic field problems-electrostatic field problems. Based on Laplace equation of electrostatic field, the derivations and solutions of SBFEM equations for both bounded and unbounded domain problems are expressed in details, and the solution for the inclusion of prescribed potential along the side-faces of bounded domain is also presented in details, then the total charges on the side-faces can be semi-analytically solved. The accuracy and efficiency of the method are illustrated by numerical examples of electromagnetic field problems with complicated field domains, potential singularities, inhomogeneous media and open boundaries. In comparison with analytic solution method and other numerical methods, the results show that the present method has strong ability to resolve potential field singularities analytically by choosing the scaling centre at the singular point, has the inherent advantage of solving the open boundary problems without truncation boundary condition, has efficient application to the problems with inhomogeneous media by placing the scaling centre in the bi-material interfaces, and produces more accurate solution than conventional numerical methods with far less number of degrees of freedom. The method in electromagnetic field calculation can have broad application prospects.
Hostile dynamic loadings such as severe wind storms, earthquakes, and sudden impacts can cause severe damage to many civil engineering structures. An intelligent structural system equipped with smart structural member...
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Hostile dynamic loadings such as severe wind storms, earthquakes, and sudden impacts can cause severe damage to many civil engineering structures. An intelligent structural system equipped with smart structural members that are controllable in real-time is an effective solution to structural damage and failure during such situations. Civil intelligent structures with controllable properties to adapt to any changes due to dynamic loadings can lead to effective protection of structures and their occupants. In this paper, design and testing of a semi-active magnetor-heological (MR) pin joint, in which the moment resistance can be controlled in real-time by altering the magnetic field, is reported with the view of using it as a potential candidate for smart members in the development of intelligent structures. Design of prototype smart pin joints includes theoretical analysis related to the radius of the rotary plate, the property of MR fluids and the gap between the rotary plate and the casing based on the requirements of the dynamics of MR pin joints. FEM analysis was deployed to study the distribution of the magnetic field along the gap. It is found, from the theoretical analysis and experimental verification, that the MR pin joint with a diameter of 180 mm can produce a torque of up to 30Nm,which meets requirements for semi-active members in a multi-storey prototype building model in the next stage of research and development.
Suspended solids (SS) in the first-flush runoff on highway was monitored in six continuous events from October to December 2000 in Winterthur, Switzerland, and some characteristics of particle-bound micropollutants su...
Suspended solids (SS) in the first-flush runoff on highway was monitored in six continuous events from October to December 2000 in Winterthur, Switzerland, and some characteristics of particle-bound micropollutants such as polycyclic aromatic hydrocarbons, phthalate esters, and heavy metals were investigated. Among the three micropollutants, concentration of polycyclic aromatic hydrocarbon showed similar behavior to SS. Phthalate esters showed almost no correlation, whereas heavy metals showed increase in its concentration with lowers SS concentration. Three different characteristics of the micropollutants in the first flush indicated that the first-flush phenomenon is complex, and they may not be simply stated when considering suspended solids as an index for the runoff.
In any flash flood evacuation operation, vehicle assignment at the inundated areas is vital to help eliminate loss of life. Vehicles of various types and capacities are used to evacuate victims to relief centers. This...
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In any flash flood evacuation operation, vehicle assignment at the inundated areas is vital to help eliminate loss of life. Vehicles of various types and capacities are used to evacuate victims to relief centers. This paper examines combinatorial optimization approach with the objective function to assign a specified number of vehicles with maximum number of evacuees to the potential inundated areas. Discrete particle swarm optimization (DPSO) and improved DPSO are proposed and experimented on. Results are presented and compared. Improved DPSO with the proposed min-max approach yields better performance for all four testing categories. Experimenting on a large number of evacuees could further improve the performance of the DPSO.
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