Papers by Keyword: Numerical Method

Abstract: The particles distinct element model has the consistency to model the mechanical behavior of the microscopic structures inside an asphalt mixture. The model assumes that the schematized granular constituents are in a contact point, considering the thin asphalt films as the binding elements. In this paper, we will model (at micro-scale) the damage to a surface in asphalt concrete under an impulsive load, considering binding, interface, viscosity and friction. Our aim is to reproduce the micro-damage due to detachment among the elementary components of the concrete in airports pavements.The proposed approach is mainly from a mechanical point of view, and a general model describing adhesive contact between rigid bodies is proposed. The intensity of adhesion is supposed to decrease under prescribed shear and normal displacement fields and comes by energy reduction, where the viscosity and friction contributes are taken in account.A numerical implementation by finite element procedures has been performed, and the outcome is presented.

Abstract: Numerical method is used to build the entity model and finite element model of a marine pump, modal analysis shows that modal frequency is not equal to the operating frequency and the resonance is not produced in the pump. The finite element method is used to calculate the shock load which is the request of GJB. The allowable strength at vertical, longitudinal and horizontal direction of the pump is analyzed, and the anti-shock behavior of the pump is checked too. The results show this type pumps are not destroyed wholly and can be working normally in the shock environment, which satisfy the requirements of GJB. But the bracket position of the pump is suffered great compressive stress which leads to the designed and strengthened again.

Abstract: This paper presents the comparison between various numerical methods namely Euler's Method, Midpoint Method, 2nd order Runge Kutta Method and 4th order Runge Kutta Method with the analytical method to solve a power electronic system in both single phase and three phase configuration using decoupled methodology. The values of source current, load current and DC link voltage are obtained for each method using Matlab software and compared with each other. Also, the error in each numerical method with respect to analytical method is calculated and tabulated. These power electronic models could be an excellent research platform for testing the renewable energy systems without going for full scale or scaled down models.

Abstract: Gas jet of the rocket on the launch environment has serious gas shock effects, bursts of rocket impact will be greater and greater harm. This article take the numerical methods for simulation, analog transmission process gas stream flow, and finally calculate the pressure and temperature of the emitting device impingement flow field and the maximum absolute pressure and temperature, and ultimately determine gas impact of the danger zone of the flow field.

Abstract: Yoshida-Uemori model (Y-U model) can be used with any types of yield functions. The calculated stress strain response will be, however, different depending on the chosen yield function if the yield function and the effective strain definition are inappropriate. Thus several modifications to Y-U model were proposed in the 10th International Conference on Technology of Plasticity. It was ascertained that in the modified Y-U model, the same set of material parameters can be used with von Mises, Hill’s 1948, and Hill’s 1990 yield function. In this study, Yld2000-2d and Yoshida’s 6th-order polynomial type 3D yield function were examined and it was clarified that the same set of Y-U parameters can be used with these yield functions.

Abstract: With full development of 350km/h high-speed rail network in China, further research in the key technology of 380km/h or higher super-speed rail system has become crucial. Applying the simulation of pantograph-catenary interaction based on infinite element method, this paper simulated the dynamic performance of pantograph-catenary system for high-tension overhead contact system at over 350km/h. The research findings showed that wave propagation speed can still serve as a brief computing method for the running speed within the range of 350-400km/h. When the running speed reaches 80% of the wave propagation speed or higher, the current-carrying quality of double-pantograph-catenaries system might not satisfy the standard of EN 50367 all the time.

Abstract: The finite difference method is applied to derive approximate solutions for the elasto-plastic bending of Euler-Bernoulli beam problems. The investigations are restricted to a simple exemplary configuration, i.e. a straight cantilevered beam with constant rectangular cross-section and linear-elastic/ideal-plastic material properties, loaded by a constant distributed load. Only finite difference approximations of second-order accuracy are considered and special emphasis is given to the influence of the load step, the number of layers, and the number of nodes. Based on comparisons with the analytical solution, clear recommendations can be given on the required parameters to obtain a certain accuracy in the numerical approach.

Abstract: We report a modification method for Gold target by intense pulsed ion beam (IPIB) irradiation. Based on the temporal and spatial distribution models of the ion beam density detected by Faraday cup in the chamber and the ions accelerating voltage, the energy deposition of the beam ions in Au is calculated by Monte Carlo method. Taking this time-dependent nonlinear deposited energy as the source term of two-dimensional thermal conduction equation, we obtain the temporal and spatial ablation process of metal Au during a pulse time. The top-layer Gold material in thickness of about 0.25μm is ablated by vaporization and the layer in thickness of 1.40μm is melted after one shot at the ion beam density of 300 A/cm2.

Abstract: This paper presents numerical investigations of the thermal and fluid flow behavior in an L-shaped of cavity filled with nanofluid. The left and bottom walls are heated to higher temperature than the horizontal upper and right vertical walls. The results show that the characteristic of flow and heat transfer are critically dependent on the dimensionless Rayleigh number. We also found that the presence of nanoparticle enhances the heat transfer rate in the enclosure.

Abstract: A non-linear numerical method of composite foundation with rigid-flexible piles in the stratified soil under the vertical load was established in this paper. The analytical model of the pile-soil-pile interaction was used to imitate the pile-soil system and the finite element method was applied to simulate the cushion (the cushion cap). The corresponding calculation program was programmed. Computation results show that the method is reasonable and feasible, and can be applied to the analysis of practical composite foundation.