We introduce an algorithm for the explicit treatment of contact line motion for thin-film problems and compare its solutions with exact source-type solutions and their asymptotic behavior near the contact line. The al...
详细信息
We introduce an algorithm for the explicit treatment of contact line motion for thin-film problems and compare its solutions with exact source-type solutions and their asymptotic behavior near the contact line. The algorithm uses a variational formulation and avoids dealing with singularities near the contact line. (C) 2015, IFAC (International Federation of Automatic Control) Hosting, by Elsevier Ltd. All rights reserved.
In this paper, the implementation of the finite difference WENO scheme maintaining velocity, pressure and temperature equilibrium in the multicomponent compressible fluid analysis is discussed. First, the new finite d...
详细信息
A computationally efficient solution scheme is presented for the mechanical problems whose formulations include the Kuhn-Tucker or Signorini-Fichera conditions. It is proposed to reformulate these problems replacing i...
详细信息
A computationally efficient solution scheme is presented for the mechanical problems whose formulations include the Kuhn-Tucker or Signorini-Fichera conditions. It is proposed to reformulate these problems replacing inequalities in these conditions by equations with respect to new unknowns. The solutions of the modified problems have simple physical meanings and determine uniquely the unknowns of the original problems. The approach avoids application of multi-valued operators (inclusions or inequalities) in formulation of the problems. Hence, the modified formulations are suitable for numerical analysis using established powerful mathematical methods and corresponding solvers developed for solving systems of non-linear equations. To demonstrate the advantages of the proposed approach, it is applied for solving problems in two different areas: constitutive modeling of single-crystal plasticity and mixed boundary value problems of elastic contact mechanics with free boundaries. The original formulations of these problems contain respectively the Kuhn-Tucker and Signorini-Fichera conditions. A problem of the former area is integrated using an implicit integration scheme based on the return-mapping algorithm. The derived integration scheme is free of any update procedure for identification of active slip systems. A problem of the latter area is reduced to solution of non-linear integral boundary equations (NBIEs). numerical examples demonstrate stability and efficiency of the solution procedures and reflect the mathematical similarities between the both non-linear problems. (C) 2013 Elsevier Ltd. All rights reserved.
We introduce an algorithm for the explicit treatment of contact line motion for thin- film problems and compare its solutions with exact source-type solutions and their asymptotic behavior near the contact line. The a...
详细信息
We introduce an algorithm for the explicit treatment of contact line motion for thin- film problems and compare its solutions with exact source-type solutions and their asymptotic behavior near the contact line. The algorithm uses a variational formulation and avoids dealing with singularities near the contact line.
This paper proposes an algorithm to design switching surfaces for the switching linear parameter-varying (LPV) controller with hysteresis switching. The switching surfaces are sought for to optimize the bound of the c...
详细信息
ISBN:
(纸本)9781479932740
This paper proposes an algorithm to design switching surfaces for the switching linear parameter-varying (LPV) controller with hysteresis switching. The switching surfaces are sought for to optimize the bound of the closed-loop L-2-gain performance. An optimization problem is formulated with respect to parameters characterizing Lyapunov matrix variables, local controller matrix variables, and locations of the switching surfaces. Since the problem turns out to be nonconvex in terms of these characterizing parameters, a numerical algorithm is given to guarantee the decrease of the cost function value after each iteration. A hybrid method which combines the steepest descent method and Newton's method is employed in each iteration to decide the update direction of switching surface parameters. A simple numerical example is provided to demonstrate the validity of the proposed algorithm.
Numerous numerical simulations and analysis were performed to understand the phenomenon of space charge packets. In theory, the simulation of charge packet transport is based on the three physics principles: transport...
详细信息
ISBN:
(纸本)9781479989041
Numerous numerical simulations and analysis were performed to understand the phenomenon of space charge packets. In theory, the simulation of charge packet transport is based on the three physics principles: transport equation, continuity equation and Poisson's equation. As a key equation to simulate charge packet problem, it's very important to select an appropriate numerical algorithm to solve transport equation. For the sake of simplicity, supposed there is no charge injection at the electrode, without trapping and de-trapping process, and neglecting the influence of small charge packet on the applied electric field, three algorithms, FTCS Scheme, First Order Upwinding Scheme and QUICKEST Scheme, are used for solving transport equation. The results show that when the charge packet migrates across the sample, its amplitude becomes larger and the width gets narrower by using the FTCS, however, smaller and broader by the First Order Upwinding Scheme. By comparison, the charge packet can almost keep its shape by the QUICKEST Scheme, but with a relatively lower computing efficiency. When combining the objective and subjective evaluation results, it seems that QUICKEST is the most suitable compromise for the transport equation.
Reachable domain refers to the collection of all positions accessible for a spacecraft under a given initial orbit and fuel constraint with free time of flight. In this study, the fuel constraint is conveniently expre...
详细信息
Reachable domain refers to the collection of all positions accessible for a spacecraft under a given initial orbit and fuel constraint with free time of flight. In this study, the fuel constraint is conveniently expressed by a single available velocity impulse. To solve the envelope of the reachable domain, the radius of an accessible target position in a given direction is formulated. By evaluating the extreme values of the accessible radius in the given direction, two reachable boundaries and a reachable line segment are solved. The reachable domain in three-dimensional space is determined by rotating the direction and tracing all the reachable boundaries. The proposed method successfully solves the envelope of the reachable domain for the remaining two unresolved scenarios: the reachable domain with an arbitrary maneuver point and arbitrary impulse direction and the reachable domain with an arbitrary maneuver point and fixed impulse direction. This is the first time the accurate envelope of the reachable domain has been described in three-dimensional space. Acomparison of the results of the proposed numerical simulations with those of the existing method demonstrates the accuracy of the proposed method.
The role of interstitial carbon impurities on the dislocation glide in bcc iron is investigated by means of molecular dynamics simulations. The local stress induced by carbon atoms, interaction energy map for the a(0)...
详细信息
The role of interstitial carbon impurities on the dislocation glide in bcc iron is investigated by means of molecular dynamics simulations. The local stress induced by carbon atoms, interaction energy map for the a(0)/2 < 111 >{110} and a(0)/2 < 111 >{112} edge dislocations and the dynamics of dislocation carbon interaction is assessed. The local stress exerted on the dislocation due to the carbon atoms and computed by atomistic simulations is used to describe the interaction strength on the continuum level. The derived here analysis of the atomistic data enabled the determination of the activation enthalpy and volume as a function of stress. Having that information, a comparative study demonstrates that at finite temperature, the resistance to the dislocation glide induced by the carbon atoms is lower in {112} than in {110} slip systems. (C) 2014 Elsevier Ltd. All rights reserved.
暂无评论