Simulation of Nonlinear Multiport Systems Using Bond Graphs

1973 ◽  
Vol 95 (1) ◽  
pp. 49-54 ◽  
Author(s):  
H. R. Martens
Keyword(s):  
Original System ◽  
Differential Algebraic Equations ◽  
Newton Iteration ◽  
System Of Equations ◽  
Algebraic Equations ◽  
Bond Graphs ◽  
First Order ◽  
Nonlinear Algebraic Equations ◽  
Previous Solution ◽  
Speed And Accuracy

An approach for the computer simulation of nonlinear multiport systems is presented. Bond graph techniques are utilized in the development. The objective of the formulation is to derive a system of mixed first-order differential/algebraic equations, whose solution is facilitated by approximating the derivatives by a linear combination of the present and several previous solution points. Thus the original system of equations is converted to a system of implicit nonlinear algebraic equations which are solved by a Newton iteration procedure. The formulation procedure lends itself to mechanization similar to ENPORT. Computational results from an illustrative example show the method to be excellent in speed and accuracy relative to other simulation approaches.

Direct Differentiation Methods for the Design Sensitivity of Multibody Dynamic Systems

1996 ◽  
Author(s):  
Radu Serban ◽  
Jeffrey S. Freeman
Keyword(s):  
Sensitivity Analysis ◽  
Dynamic Systems ◽  
Design Sensitivity ◽  
Differential Algebraic Equations ◽  
Mechanism Analysis ◽  
Algebraic Equations ◽  
First Order ◽  
Direct Differentiation ◽  
Multibody Dynamic ◽  
Standard Techniques

Abstract Methods for formulating the first-order design sensitivity of multibody systems by direct differentiation are presented. These types of systems, when formulated by Euler-Lagrange techniques, are representable using differential-algebraic equations (DAE). The sensitivity analysis methods presented also result in systems of DAE’s which can be solved using standard techniques. Problems with previous direct differentiation sensitivity analysis derivations are highlighted, since they do not result in valid systems of DAE’s. This is shown using the simple pendulum example, which can be analyzed in both ODE and DAE form. Finally, a slider-crank example is used to show application of the method to mechanism analysis.

scholarly journals Numerical solution for consistent initial conditions of constrained mechanical systems

2003 ◽  
Vol 25 (3) ◽  
pp. 170-185
Author(s):  
Dinh Van Phong
Keyword(s):  
Numerical Solution ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Differential Algebraic Equations ◽  
System Of Equations ◽  
Algebraic Equations ◽  
Flexible Approach ◽  
Constrained Mechanical Systems ◽  
Consistent Initial Values

The article deals with the problem of consistent initial values of the system of equations of motion which has the form of the system of differential-algebraic equations. Direct treating the equations of mechanical systems with particular properties enables to study the system of DAE in a more flexible approach. Algorithms and examples are shown in order to illustrate the considered technique.

Well-Posed Formulations for Nonholonomic Mechanical System Dynamics

2020 ◽  
Vol 15 (10) ◽  
Author(s):  
Edward J. Haug
Keyword(s):  
System Dynamics ◽  
Mechanical System ◽  
Lagrange Multiplier ◽  
Variational Formulation ◽  
Direct Consequence ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
First Order ◽  
Well Posed ◽  
Problem Data

Abstract Four formulations of nonholonomic mechanical system dynamics, with both holonomic and differential constraints, are presented and shown to be well posed; i.e., solutions exist, are unique, and depend continuously on problem data. They are (1) the d'Alembert variational formulation, (2) a broadly applicable manifold theoretic extension of Maggi's equations that is a system of first-order ordinary differential equations (ODE), (3) Lagrange multiplier-based index 3 differential-algebraic equations (index 3 DAE), and (4) Lagrange multiplier-based index 0 differential-algebraic equations (index 0 DAE). The ODE formulation is shown to be well posed, as a direct consequence of the theory of ODE. The variational formulation is shown to be equivalent to the ODE formulation, hence also well posed. Finally, the index 3 DAE and index 0 DAE formulations are shown to be equivalent to the variational and ODE formulations, hence also well posed. These results fill a void in the literature and provide a theoretical foundation for nonholonomic mechanical system dynamics that is comparable to the theory of ODE.

scholarly journals Nonlinear elliptic problems with the method of finite volumes

2006 ◽  
Vol 2006 ◽  
pp. 1-16 ◽  
Author(s):  
Sanjay Kumar Khattri
Keyword(s):  
Nonlinear Partial Differential Equations ◽  
Nonlinear Partial Differential Equation ◽  
Elliptic Problems ◽  
System Of Equations ◽  
Algebraic Equations ◽  
Nonlinear Elliptic Problems ◽  
Partial Differential ◽  
Nonlinear Elliptic ◽  
Finite Volume Discretization ◽  
Nonlinear Algebraic Equations

We present a finite volume discretization of the nonlinear elliptic problems. The discretization results in a nonlinear algebraic system of equations. A Newton-Krylov algorithm is also presented for solving the system of nonlinear algebraic equations. Numerically solving nonlinear partial differential equations consists of discretizing the nonlinear partial differential equation and then solving the formed nonlinear system of equations. We demonstrate the convergence of the discretization scheme and also the convergence of the Newton solver through a variety of practical numerical examples.

Comparison of Modeling Techniques for a Landing Gear

2010 ◽  
Author(s):  
Rebecca Margetts ◽  
Roger F. Ngwompo
Keyword(s):  
Block Diagram ◽  
Differential Algebraic Equations ◽  
Landing Gear ◽  
Algebraic Equations ◽  
Bond Graphs ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Wide Range ◽  
Modeling Techniques ◽  
Computational Errors

A wide range of modeling techniques is available to the engineer. The objective of this paper is to compare some typical modeling techniques for the simulation of a multi-domain mechatronic system. Usual dynamic modeling methods, such as block diagrams and iconic diagrams, can cause problems for the engineer. Differential algebraic equations (DAEs) and algebraic loops can significantly increase simulation times and cause numeric errors. Bond graphs are less common in industry, and are presented here as a method which allows the engineer to easily identify causal loops and elements in differential causality. These can indicate DAEs in the underlying equations. An aircraft landing gear is given as an example of a multi-domain system, and is modeled as a block diagram, an iconic diagram and as a bond graph. The time to construct the model, time to solve and problems faced by the analyst are presented. Bond graphs offer distinct advantages in terms of the ease of implementing algebraic equations and visibility of causality. The time taken to model a system can be significantly reduced and the results appear free from computational errors. Bond graphs are therefore recommended for this type of multi-domain systems analysis.

scholarly journals A family of modified Newton iteration method for solving nonlinear algebraic equations

2017 ◽  
Vol 20 (K2) ◽  
pp. 34-41
Author(s):  
Luc Xuan Nghiem ◽  
Hieu Nhu Nguyen
Keyword(s):  
Iteration Method ◽  
Order Of Convergence ◽  
Approximate Solutions ◽  
Newton Iteration ◽  
Convergence Order ◽  
Correction Function ◽  
Algebraic Equations ◽  
Order Condition ◽  
Nonlinear Algebraic Equations ◽  
Newton Iteration Method

In this study, a modified Newton iteration version for solving nonlinear algebraic equations is formulated using a correction function derived from convergence order condition of iteration. If the second order of convergence is selected, we get a family of the modified Newton iteration method. Several forms of the correction function are proposed in checking the effectiveness and accuracy of the present iteration method. For illustration, approximate solutions of four examples of nonlinear algebraic equations are obtained and then compared with those obtained from the classical Newton iteration method.

scholarly journals THE MATHEMATICAL MODELLING OF THE NONLINEAR HEAT TRANSPORT IN THIN PLATE

1999 ◽  
Vol 4 (1) ◽  
pp. 44-50
Author(s):  
A. Buikis
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Mathematical Modelling ◽  
Heat Transport ◽  
Initial Value Problem ◽  
Nonlinear Ordinary Differential Equations ◽  
Algebraic Equations ◽  
Initial Value ◽  
First Order ◽  
Nonlinear Algebraic Equations

The approximations of the nonlinear heat transport problem are based on the finite volume (FM) and averaging (AM) methods [1,2]. This procedures allows reduce the nonlinear 2‐D problem for partial differential equation (PDE) to a initial‐value problem for a system of 2 nonlinear ordinary differential equations(ODE) of first order in the time t or to a initial‐value problem for one nonlinear ODE of first order with two nonlinear algebraic equations.

Solvability conditions in the analytical form of a descriptor system of partial differential equations

2021 ◽  
pp. 130-142
Author(s):  
Abdulftah H. Mohamad
Keyword(s):  
Original System ◽  
Analytical Form ◽  
Differential Algebraic Equations ◽  
Operator Pencil ◽  
Descriptor System ◽  
Algebraic Equations ◽  
Partial Differential ◽  
Solvability Conditions ◽  
Partial Differential Algebraic Equations ◽  
Degenerate Operators

A system of first-order partial differential-algebraic equations in a Banach space with constant degenerate operators in the case of a regular operator pencil is considered. In this case, under some additional condition, the original system splits into two subsystems in disjoint subspaces in order to search for the projections of the original unknown function in the subspaces. The matching conditions for the parameters of the systems are identified. A solution of the considered system of differential-algebraic equations is constructed.

scholarly journals Regularization of Operator DAEs

2015 ◽  
Author(s):  
Robert Altmann
Keyword(s):  
General Framework ◽  
Stokes Equations ◽  
Differential Algebraic Equations ◽  
Navier Stokes ◽  
Algebraic Equations ◽  
Spatial Discretization ◽  
Navier Stokes Equations ◽  
First Order ◽  
Index 2 ◽  
Differentiation Index

A general framework for the regularization of constrained PDEs, also called operator differential-algebraic equations (DAEs), is presented. For this, we consider semi-explicit systems of first order which includes the Navier-Stokes equations. The proposed reformulation is consistent in the sense that the solution of the PDE remains untouched. However, one can observe improved numerical properties in terms of the sensitivity to perturbations and the fact that a spatial discretization leads to a DAE of lower index, i.e., of differentiation index $1$ instead of differentiation index 2.

Endochronic Simulation on the Effect of Curvature Rate at the Preloading Stage on the Subsequent Creep or Relaxation of Thin-Walled Tubes Under Pure Bending

2011 ◽  
Vol 27 (4) ◽  
pp. 511-519 ◽  
Author(s):  
K.-H. Chang ◽  
C.-Y. Hung
Keyword(s):  
Experimental Data ◽  
Virtual Work ◽  
Algebraic Equations ◽  
Principle Of Virtual Work ◽  
Pure Bending ◽  
Endochronic Theory ◽  
First Order ◽  
Nonlinear Algebraic Equations ◽  
Thin Walled ◽  
Theoretical Simulations

ABSTRACTIn this paper, the first-order ordinary differential constitutive equations of endochronic theory were combined with the principle of virtual work for simulating the response of creep (moment is kept constant for a period of time) or relaxation (curvature is kept constant for a period of time) of thin-walled tubes subjected to pure bending with different curvature-rates at the preloading stage. A group of Fourier series was used to describe the circumferential displacements of the tube. Thus, a system of nonlinear algebraic equations was determined. This system of equations can be solved by numerical method. Experimental data tested by Pan and Fan [1] were compared with the theoretical simulations in this study. It is shown that the theoretical formulations effectively simulate the experimental data.

Sign in / Sign up

Export Citation Format

Share Document