Papers by Keyword: Computational Micromechanics Method

Abstract: A new rapid computation method for Kalman filtering is proposed. In this method, the prediction of state covariance matrix is expanded directly rather than computing by a looping program. Sequential filtering for measurement update is also applied. Furthermore, the subsidiary elements in system matrix are set to zero and a reduced-dimensions sub-optimal Kalman filter is presented. The proposed method greatly decreases computational burden and it is only 6.59% of the classic method. In the end, a vehicular test is carried out to prove the feasibility of the filtering.

Abstract: Since the water resourse insome towns of Beijing were in a big shortage in the past few years, it becomes a key factor which restricts the sustainable development and theurbanlization of Beijing. Based on the fact, this paper introduces the reserrch situation and development of the ecological footprint of urban water resourse in Beijing. And it puts forward the method for calculating the the ecological footprint of urban water resourse , includeing domestic water, process water and eological water, in Beijing. Furthermore, the computational method of ecological carrying capacity and ecological deficit of urban water resourse in Beijing is proposed, which provides reference for the evaluation of ecological capacity of urban water resourse in Beijing.

Abstract: Subway construction involves a large number of excavation engineering. For the restrictions caused by conditions on the spot,Many foundation pits projects showed some features of clear spatial effects, complex stress characteristics,multiplex affecting factors, it often can not be suit for the applicable conditions of the existed earth pressure theory very well. On the background of BeiLing Station Passageway construction in Shenyang Subway Line No.2, Through counting and analyzing the results of three-dimensional numerical simulation in detail,summing up regulations of Taishan bridge abutment displacement in the horizontal plane. Force act on 4,5foundations fender post present trapezium and parabola distribution with depth respectively. So it is concluded the properties of foundation pit earth pressure, proposing a simple calculating model comparing its results with numerical simulation results to verify the reasonableness of the model. So the problem which is how to calculate the earth pressure under the complexity of obvious spatial effects and a variety of environmental conditions can be solved and reference experiences on the calculation of earth pressure can be provided to similar Follow-up projects

Abstract: In view of the issues of computational method combined execution that need parameters transfer in the process of complex product engineering analysis, the execution principle and parameter file formats of computational method are discussed. Through parsed the computational parameters, the mapping relationship among multi-computational methods are established and parameters passing between computational methods is realized. A product design analysis environment system, called PDAE, is developed. With the application of PDAE in the analysis process for CFB boiler and turbo-generator, the feasibility and validity of the approach proposed is demonstrated.

Abstract: A three dimensional FE modeling of the laser surface modification is presented. The design capabilities of the ANSYS (11) software were employed for this purpose. The model calculates the dimensions of melting zone and heat affected zone. Model simulations are compared with experimental results that showed very good agreement. A one dimensional model in V.B language was presented too. The model based on conduction of heat in one dimension neglecting the other losses of heat. The results of VISUAL BASIC were compared with experimental results which showed a very good agreement. The two methods were compared with each other to showing which method have a good prediction compared with experimental results in calculating of fusion zone and heat affected zone "HAZ".

Abstract: A mathematical model to simulate the natural dam break process and to forecast the flood hydrograph in the breach is developed in this paper. The breach is assumed trapezoidal, coupling with the bottom width and side slope angle keeping constants during the overall process of dam breach. Simulation of dam breach evolution is based on the conservation of mass of reservoir capacity and sediment transport capacity. Particularly, broad-crest weir relation is utilized to simulate the outflow in the breach, and an empirical equation is used to compute the rate of erosion in the breached section. Because of the implicit form of these equations, an iterative solution is proposed with convergence achieved in a few iterations. The model can be used by engineers or decision makers for a wide range of applications including risk assessment of natural dams, flood routing forecasting in the downstream reach as well as floodplain inundation mapping .

Abstract: A structure with “changeable boundaries”, changed from construction stage to service stage, is a new design idea used in long span spatial structures. The inner force distribution will be more reasonable and the structure self-weight will be lighter, if the idea is adopted. Adoption of the idea enables the inner force distribution of the structure changing from the construction stage to the service stage. Although the time of the inner force changing is much short, it has a significant influence on the loading behavior and the construction cost of the structure. As an example, a simple beam with different boundaries (unchangeable and changeable), under uniformly distributed lateral loads, is analyzed in this paper. Through static analysis, the loading behavior of the beam under three different boundaries, including simple support, fixed support and changeable boundary, is compared. The linear buckling behavior of the beam with changeable boundaries is also investigated. The critical equilibrium equation is derived subsequently for computing the critical stability load. A new computation method for the beam with changeable boundaries is proposed.

Abstract: In this paper, a new computational method is proposed for solving a class of optimization problems which have broad applications in production system and system engineering. Firstly, by exploiting structure of the problem, linear relaxation programming of the original problem is constructed. By using simplex method we can solve a sequence of linear relaxation programming, the proposed algorithm is convergent to the global minimum of original problem through the successive refinement of the feasible region of a series of linear programming problems. In finally, numerical experiments are given to show the feasible of the proposed method.

Abstract: It is difficult and important to accurately calculate single pile ultimate bearing capacity during pile foundation design. Typical computational methods on single pile ultimate bearing capacity are contrastively analyzed in this paper. Contact element method on single pile ultimate bearing capacity is relatively accurate and economical, but it isn’t used in practical projects until now because its computational process is complicated. 343 different single pile ultimate bearing capacities are calculated with the contact element method in order to study a simple computational formula based on the contact element method. All data calculated are analyzed with a linear recursive multi-analysis program which is programmed with Fortran90. A simple computational formula on the contact element method is presented based on the analysis results. The simple computational formula, the experiential formula in the code, the contact element method and the static load experiment method are respectively used to calculate single pile ultimate bearing capacity in two practical projects in order to test the simple computational formula. The results show that the simple computational formula is relatively accurate. Some advice is presented based on the analysis results.

Abstract: An investigation into three dimensional fluid flow has been conducted which combines the use of Computational Fluid Dynamics (CFD) simulations with the experimental phenomenon of Streaming Birefringence. A versatile flow channel was designed and built for use in conjunction with a circular polariscope. The experimental liquid used was an aqueous solution of a dye, commercially known as Milling Yellow NGS with the addition of Sodium Chloride. To extract the flow fields, six image phase stepping photoelasticity was used over backward and forward steps, and flows around a cylinder, and full-field fringe data were obtained. This method needs laminar flow regimes and the Reynolds number of the flow was around 10. To allow direct comparisons of the CFD solutions with the optical results, a macro (UDF) was written to interpret the flow field results from a (FLUENT6) CFD simulation. This integrated the shear stresses across the flow field and banded the results into fringes. A good correlation between the simulated fringes and the shearstrain rate was obtained from these observations.