Arthroscopic anterior cruciate ligament (ACL) reconstruction is a highly standardized procedure. To minimize the risk of technical failures and intraoperative complications, special instruments, such as dedicated dril...
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Arthroscopic anterior cruciate ligament (ACL) reconstruction is a highly standardized procedure. To minimize the risk of technical failures and intraoperative complications, special instruments, such as dedicated drill guides, have been developed. However, each surgical step still implies specific complications. Thus, it is of great importance to know the technique used and its instruments as well as solution algorithms in detail. This article explains intraoperative complications in ACL reconstruction. Furthermore, specific techniques to solve, and particularly to prevent these complications are discussed.
An approach is proposed to solve dynamic problems for discrete-continuous flexible one-dimensional systems with nonpotential deformation characteristics. The approach is based on a generalized stationarity principle. ...
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An approach is proposed to solve dynamic problems for discrete-continuous flexible one-dimensional systems with nonpotential deformation characteristics. The approach is based on a generalized stationarity principle. The solution algorithm employs cubic spline functions. A numerical example demonstrates the capabilities of this approach in determining the loads and displacements in such a system under external influence.
In this paper, we are concerned with identifying more efficient algorithms for solving dynamic traffic assignment with departure time choice problem using a discrete time simulation-based model. We compare and evaluat...
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ISBN:
(纸本)9789889884710
In this paper, we are concerned with identifying more efficient algorithms for solving dynamic traffic assignment with departure time choice problem using a discrete time simulation-based model. We compare and evaluate the performance of two heuristic algorithms: method of successive averages (MSA) and "route-swapping" algorithm. The two algorithms are tested in an example grid network, and convergence and stability of the proposed algorithms are discussed.
This paper discusses the necessity and handling of non-linear constraint equations to describe the behaviour of properties of the loading system such as, e.g. smooth free-rotating loading platens. An exact, non-linear...
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This paper discusses the necessity and handling of non-linear constraint equations to describe the behaviour of properties of the loading system such as, e.g. smooth free-rotating loading platens. An exact, non-linear formulation for a smooth loading platen is derived and its incorporation into the equilibrium equations is presented. For this purpose, the Lagrange multiplier method is used. The solution of the equilibrium equations by means of a Newton-Raphson algorithm is also outlined. The proposed approach is validated on a patch of two finite elements and applied to a compression-bending test on a pre-notched specimen. It is observed that use of a linearized approximation of the boundary constraint can lead to errors in the description of the motion of the constrained nodes. Thus, the non-linear formulation is preferable. Copyright (C) 2002 John Wiley Sons, Ltd.
This. paper discusses parametric reform options to control losses generated by a publicly managed pay-as-you-go (PAYG) pension system under alternative deficit reduction (reform) strategies involving changes in contri...
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This. paper discusses parametric reform options to control losses generated by a publicly managed pay-as-you-go (PAYG) pension system under alternative deficit reduction (reform) strategies involving changes in contribution and replacement rates and statutory retirement ages. Two different problems corresponding to different pension reform strategies are considered using computational techniques. The techniques are illustrated through exercises employing data for the financially troubled pension system in Turkey. (C) 2001 Elsevier Science B.V. All rights reserved.
The paper describes how quasi-static, conservative instability problems can be seen in a multi-dimensional context, and how one- and two-dimensional solution manifolds can reveal further information on the structural ...
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The paper describes how quasi-static, conservative instability problems can be seen in a multi-dimensional context, and how one- and two-dimensional solution manifolds can reveal further information on the structural response. The discussed viewpoint can be seen as the natural extension of the common one-dimensional path-following methods, when additional variables are introduced to describe the parameter dependence in structural response, instability analyses and optimization. The paper describes the general setting of the generalized equilibrium problems, and discusses their numerical treatment for the cases of resulting one- and two-dimensional solution sets. Numerical examples show some applications of these models, and describe the possibilities and properties of the obtained solution sets.
Real-time dynamic simulation of large, realistic and complex multibody systems is essential in developing modern technologies such as virtual prototyping, man-in-the-loop simulators and intelligent vehicle control sys...
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Real-time dynamic simulation of large, realistic and complex multibody systems is essential in developing modern technologies such as virtual prototyping, man-in-the-loop simulators and intelligent vehicle control systems. In order to achieve real-time performance, current commercial codes require the use of large costly computers, thus limiting the number of potential users. This paper shows that real-time can be achieved on medium-size workstations if, on the one hand, an adequate combination of modeling, dynamic formulation, and numerical integration scheme is selected and, on the other hand, advantage is taken of sparse matrix technology and parallel computing. A study of space-state and descriptor methods involving the dynamics of a whole vehicle model is carried out and in conclusion, two methods are proposed as the best candidates for real-time simulation.
This project integrates lecture material on computational methodology for viscous flows with hands-on exposure to code development, validation, and case running, all in a context suitable for varying programming skill...
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This project integrates lecture material on computational methodology for viscous flows with hands-on exposure to code development, validation, and case running, all in a context suitable for varying programming skill...
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This project integrates lecture material on computational methodology for viscous flows with hands-on exposure to code development, validation, and case running, all in a context suitable for varying programming skills. Students are given a well-documented, partially completed code for solving the boundary-layer equations. They recreate the missing parts in accordance with material covered in lectures and then compute laminar and turbulent flows. Examples of results are given. (C) 1997 John Wiley & Sons, Inc.
The simplified perturbed hard chain theory (SPHCT) equation of state (EOS) possesses several attractive features. We have been exploring possible modifications to the equation to improve its performance for both equil...
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The simplified perturbed hard chain theory (SPHCT) equation of state (EOS) possesses several attractive features. We have been exploring possible modifications to the equation to improve its performance for both equilibrium and volumetric property calculations. (In a companion study, we have outlined our strategies for modifying the SPHCT EOS.) As a precursor to our study of modifications to the SPHCT EOS, we (a) developed a robust solution algorithm for the SPHCT, (b) established a novel approach to solving the critical-point constraint equations, and (c) performed a parameter sensitivity analysis study for the equation, each of which is described in the present work, These results provided valuable guidance to our efforts in modifying the SPHCT EOS, which are presented in a companion article. The robust algorithm developed for solution of the SPHCT EOS employs a solution equation written in terms of the compressibility factor. This algorithm exhibits better behavior near both the liquid and vapor roots than previous solution equations. However, this robust behavior requires increased computation time during parameter regressions. The SPHCT parameter sensitivity analysis shows that the characteristic temperature (T*) and the maximum coordination number (Z(M)) have very strong influences on calculated vapor pressures and phase densities. Further, application of the critical constraints yields more stable parameterization than is obtained by utilizing the SPHCT equation in its original form. Simple correlations are presented for solving the critical point constraints. The correlations (a) significantly reduce computational time and complexity and (b) facilitate application of the critical point constraints without the need to embed complicated numerical routines within existing EOS computer codes.
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