Papers by Keyword: Coupling Method

Abstract: There are some coupling methods based on Finite Element Method and some other numerical methods, such as Infinite Element Method, Boundary Element Method, Finite Difference Method, etc. But these methods have their own limitations on simulation the foundation. For overcome these disadvantages, a coupling method is presented in this paper, which be proposed to analyze the effect of soil - foundation on seismic response of structures. In this coupling method, the structure and the surrounding soil are simulated with Finite Element method, and the other part of the soil with Explicit Finite Element - Finite Difference Method. Compared to other coupling methods, it is more flexible and its calculation amount is acceptable. The accuracy and effectiveness of the coupling method have been verified through Numerical experiment in this paper.

Abstract: The catalytic cracking unit, of oil refining industry, is a complex process characterized by its prolonged time delay and strong coupling ability. The unit is highly nonlinear and varies with time. Its mathematic model can be obtained online with difficulty, so as the parameters model. We describe the system of A System of Computer Real Time Optimization Control for Oil Refining Indus try ,and it is present that the system rely on coupling method of parameter identification and online simulation and synthesizing evolutionary technology of Multiple optimization strategy. It builds a single input, single output black box mathematic model. It is applied to predict the trend of system outputs, guiding the operations. This system has been adopted in several oil refineries, the benefits are pronounced.

Abstract: For solving Laplace equation in 2D unbounded domains, a natural BEM on non-uniform grid is derived and its convergence theorem is proved. The moving mesh methods for the NBEM and the NBE-FE coupling method are also studied. Numerical results confirm the efficiency of the methods.

Abstract: Considering the seepage stress coupling of fractured rock mass, the multiple holes grouting problems were simulated to analyse the spread regularity by Universal Distinct Element Code(UDEC).The results show that the correlation between grouting pressure and the diffusion distance is positive, whereas the correlation between ground stress and diffusion distance is negative; With the raising of grouting holes, the diffusion distance is increasing and becoming more uniform in all directions, and the grout pressure and saturation is falling and attenuation amplitude is decreasing along the direction of grout diffusion; With the increasing of fracture aperture, the grout diffusion distance is increasing, and the grout pressure and saturation attenuation amplitude is decreasing along the direction of grout diffusion.

Abstract: There were many issues in numerical methods of heat transfer problems such as instability at a big time step length or grid size and no-existence of inverse matrix by time-precise integration method. For sake of avoiding instability and calculating an inverse matrix, a coupling method was put forward based on EFGM and IDPIM. Formulae were deduced according to EFGM and IDPIM. Results show that the coupling method has a higher accuracy and its stability is small subjected to the time step length or grid size, and is to deserve to be popularized.

Abstract: Coupling method is developed in recent years to solve numerical problems a new method, meshless - the finite element of a direct coupling method is based on the definition of the generalized unit of coupling of the new method . The core of this method is the use of each unit in the shape function to the assumption that the brain that the whole sub-domain to be seeking to solve the unknown field function. Coupling with other compared with the method is simple to calculate the advantages of a short time.

Abstract: This research was to reveal the influence of cooling water pipe on temperature field in concrete with different numerical methods. The effect of cooling water was simulated by the finite element methods contained the approximate method and the coupling method. The results showed that the temperatures were calculated by approximate method were lower than the results of coupling method, and the largest difference in temperature was 1.52°C. The temperature gradient changed obviously near the water pipe and the effective cooling length of the water pipe along the radial direction was 0.1m. Moreover, the largest temperature error was 3.95％ in the hydration time of 24h, and away from the water pipe 0.2m through compared the results of two methods. The results would be helpful to research the combine water pipe thermal field on concrete, and predict the temperature cracks in the construction engineering.

Abstract: The finite element method has been extensively used to predict forming difficulties of die forging problems. However, the analysis for die forging problems with finite element method can lose considerable accuracy due to severely distortional meshes. Based on the equality of elements, an automatically coupling algorithm has been proposed to analyze die forging problems, which converts the FE analysis into the EFG computation to preserve the accuracy in the region where meshes have been severely distorted and still employs the FE method to ensure high computational efficiency in the region where the quality of the FE meshes is acceptable. Numerical example shows that the present algorithms exploit the respective advantages of both the FE method whose computational efficiency is high and the EFG method which can throws out mesh distortions.

Abstract: The analysis for rigid plastic forming problems with finite element method can lose considerable accuracy due to severely distortional meshes. By measuring the mesh equality of elements, a coupling algorithm for rigid plastic problems have been proposed based on the interface element method, which converts the FE analysis into the EFG computation to preserve the accuracy in the region where meshes have been severely distorted. Numerical example shows that the present algorithms exploit the respective advantages of both the FE method whose computational efficiency is high and the EFG method which can throws out mesh distortions and be suitable for rigid plastic forming analysis.

Abstract: A novel method of microemulsion coupling with sol–gel process was used for preparation of porous silica using tetraethyl orthosilicate as silicon source. Effect of solvent and catalyst on the surface texture properties was investigated respectively. The results showed that porous silica with large specific surface area (738.65 m2/g) and high pore volume (2.01 cm3/g) was obtained. However, the mesopores in silica were arranged in disorder and showed great ununiformity in shape and arrangement. To obtain porous silica with desired texture properties, an appropriate dosage of ethanol and higher HCl concentration were needed.