Papers by Author: Hai Lian Gui

Abstract: Based on experimental results and theoretical analysis at different temperatures and time of unit diffusion quantity，the chemical reaction rate in the reaction process between iron and molten tin, is investigated within the range of 260～350°C. The results indicate that the chemical reaction rate at different time decreases rapidly with the time at the same temperature, it take about four minutes to cease. Morever, the numerical value of the reaction rate at different time are close and decrease with the increasing of the temperature.

Abstract: Aiming at the problems existing in the process of shearing such as bad-section quality and low efficiency, several parameters have been changed in experiment research in the text, which is good for the wide application of this shear technology. The results of experiment agree well with shear theory.

Abstract: In the shearing process, these were many problems in shearing, the regularity of metal deformation of shearing was analyzed combined with theory of ductile damage and fracture mechanism of high-speed, the rules of factors which could be affected the shearing was analyzed on the velocity and shearing stress state. These theories would improve the shearing section.

Abstract: Fast multipole boundary element method (FM-BEM) is applied in three-dimensional elastic contact problem, but the singular integral influence calculation efficient. How to solve singular integral is become an important problem for improving FM-BEM. In this paper, Taylor series expansion and Laplace transformation were introduced; it can be used to improve the singular integral. After Laplace transformation, the singular integral is written as exponential series form, which can be suit for fast multipole method. It is not only solving singularity, but also suit fast calculation. This method improves the calculation time and calculation accurate of FM-BEM.

Abstract: The horizontal blade gap is a key problem in rolling shear. The mathematical model is established in this paper. This model is optimized based on traditional model. The optimized formula of blade clearance is obtained and the stress is analyzed in cutting process. It is benefit for improving shear quality.

Abstract: A new method named mixed fast multipole boundary element (MFM-BEM) is introduced in this paper to solve the contact problem of mill roller bearing. Incompatible elements and compatible elements are used to construct shape functions in non-contact area and contact area. On the one hand, MFM-BEM avoids satisfying the conditions of precise coordination in compatible elements, on the other hand, this method retains the merits of fast multipole boundary element method (FM-BEM). Through numerical examples, it clearly demonstrates that the calculation time and accuracy are improved. MFM-BEM provides an efficient numerical method for designing and analyzing the mill roller bearing. It also provides theoretical basis for prolonging mill roller bearing service life.

Abstract: In order to improve the efficient and accuracy, parallel algorithm of fast multipole boundary element method (FM-BEM) was presented. Combined with sparse approximate inverse preconditioning (SPAI), GMRES(m) was used to solve the equation system of FM-BEM. The parallel FM-BEM was applied to strip cold rolling process, the results obtained from parallel FM-BEM was similar with the experimental measurements. The parallel FM-BEM has more efficient and accuracy than traditional FM-BEM. This method is benefit for solving precision engineering problem.

Abstract: Based on fast multipole boundary element method (FM-BEM) and mixed variational inequality, a new method named mixed fast multipole boundary element method (MFM-BEM) was presented in this paper. In order to improve calculation time and accuracy, incompatible elements as interpolation functions were used in the algorithm. Elements were optimized by mixed incompatible elements and compatible elements. On the one hand, the difficult to satisfy precise coordinate was avoided which caused by compatible elements; on the other hand, the merits of MFM-BEM were retained. Through analysis of example, it was conclusion that calculation time and accuracy were improved by MFM-BEM, calculation continuity was also better than traditional FM-BEM. With increasing of degree of freedom, calculation time of MFM-BEM grew slower than the time of traditional FM-BEM. So MFM-BEM provided a theoretical basis for solving large-scale engineering problems.

Abstract: Based on fast multipole boundary element method (FM-BEM) and mixed variational inequality, a new numerical method named mixed fast multipole boundary element method (MFM-BEM) was presented in this paper for solving three-dimensional elastic-plastic contact problems. Mixed boundary integral equation (MBIE) was the foundation of MFM-BEM and obtained by mixed variational inequality. In order to adapt the requirement of fast multipole method (FMM), Taylor series expansion was used in discrete MBIE. In MFM-BEM the calculation time was significant decreased, the calculation accuracy and continuity was also improved. These merits of MFM-BEM were demonstrated in numerical examples. MFM-BEM has broad application prospects and will take an important role in solving large-scale engineering problems.