Simulation of Fluid Power Systems with Simcenter Amesim

Nicolae Vasiliu, Daniela Vasiliu, Constantin CĂLINOIU, Radu Puhalschi

• Editorial: CRC Press
• Año: 2018
• ISBN:
  9781351645164
• Edición: 1
• Categoría: Naturwissenschaften
• Categoría: Mechanik

This book illustrates numerical simulation of fluid power systems by LMS Amesim Platform covering hydrostatic transmissions, electro hydraulic servo valves, hydraulic servomechanisms for aerospace engineering, speed governors for power machines, fuel injection systems, and automotive servo systems

It includes hydrostatic transmissions, automotive fuel injection, hydropower speed units governor, aerospace servo systems along with case studies of specified companies

Aids in predicting and optimizing the static and dynamic performances related to the systems under study

chapter one

Overview on the numerical engineering simulation software

1.1 Introduction

Fifty years ago, Herbert E. Merritt, an eminent fluid power engineer working for the Cincinnati Machines company, Cincinnati, Ohio stated that “Actually a great deal of time and trouble can be saved if a paper and pencil analysis and design of system is made before it is simulated on a computer for final refinements.”¹ He was right for that time, but now the pencil and paper have been successfully replaced by a touch screen computer loaded with the proper simulation software. Now, a high-speed batch simulation can replace any method of optimization such as random search.

A short and comprehensive definition of simulation in industry, science, and education given in the Encyclopedia Britannica² is “a research or teaching technique that reproduces actual events and processes under test conditions. Developing a simulation is often a highly complex mathematical process. Initially, a set of rules, relationships, and operating procedures are specified along with other variables. The interaction of these phenomena creates new situations and even new rules, which further evolve as the simulation proceeds.”

The need for increasing the productivity in the design phase of manufacturing of any product led to the high-speed development of the simulation languages. First of all, the aerospace competition demanded high-performance fly control simulators. The success of the Apollo missions was facilitated by the use of Advanced Continuous Simulation Language (ACSL) written in Fortran. A huge extension of the user’s circle of this language still promoted by AEgis Technologies Group, Inc. from Alabama as ACSLX³ was demanded by the online simulation of the operation of the classic and nuclear power stations. nHance company from the United States⁴ has chosen the generic name Modular Modeling System (MMS) for this software. The project developed under this name was successfully sustained by the Electric Power Research Institute in Palo Alto, California⁵, which is an independent and nonprofit organization.

The need of the deep study of complex phenomena described by partial differential equations (PDE) leads to a strong development of the simulation program based on the Finite Element Method. Some important IT companies such as ANSYS⁶ offer a comprehensive software suite that spans the entire range of physics, providing access to virtually any field of engineering simulation that a design process requires, that is, from fluids, structures, electronics, and semiconductors to multiphysics and embedded software. Hardware-in-the-Loop (HiL) compatibility with 1D software is also available.

The basic design requirements of the fluid power systems are covered by one-dimensional (1D) simulation programs. The physical interactions with other different kinds of systems can be studied now by cosimulation with different three-dimensional (3D) programs using HiL simulation. The most important step in the field of mathematical computing software for engineers and scientists was taken by the MathWorks company⁷ that started from 1984 onward. The enhanced access of matrix laboratory (MATLAB®) and SIMULINK® to control systems, their multidomain simulation, and model-based designed has put this platform of technical computing on a lead position in modeling and design of fluid power systems by the aid of common or custom libraries.

Another important progress in 1D simulation was made by the National Instruments (NI) company, Austin, Texas⁸ in the field of innovative hardware and software applicable in many engineering fields. The control hardware using the original software created a valuable platform for the development of technical systems. The NI controllers, LabVIEW simulation, and control software can be used in any fluid power system. The compatibility of LabVIEW with the MathSCRIPT module from NI MATRIXx language widely extended the capability of solving PDE during a Real-Time simulation.

The last remarkable progress in simulation software development was achieved by Société IMAGINE from France, which created Advanced Modeling Environment for Simulation of Engineering Systems (Amesim)⁹ in 1986. The main idea of the authors (Michel Lebrun and Claude Richards) was to create very refined libraries for all industrial mechanic, hydraulic, pneumatic, thermal, and hybrid components and systems, validated by high-level manufacturers, in order to automate the design phase of any new mechatronic product without writing equations! This book is devoted to the capabilities of this software.

This introductory part is devoted to a short review of the main simulation software packages or tools used in industrial applications. The field of applications and the main capabilities of each program or platform are taken from their sites or user’s manuals with a positive regard on the performances required by the practical applications. The problems encountered by the users of these software packages or tools in finding proper solutions for their problems are not the aim of this short overview.

1.2 Free software capabilities

This short review is devoted to the free software used in the analysis and synthesis of the static and dynamic behavior of the systems from any scientific or technical field. Advanced Simulation Library, ADMB, Chapel, Euler, Fortress, FreeFem++, FreeMat, Genius, Gmsh, GNU Octave, Julia, Maxima, OpenFOAM, R, SageMath, SALOME, ScicosLab, and Scilab®, X10 are presented here.

Advanced Simulation Library (ASL)¹⁰ is a free open-source hardware accelerated multiphysics simulation software. It enables users to write customized numerical solvers in C++ and deploy them on a variety of massively parallel architectures, ranging from inexpensive field-programmable gate arrays (FPGAs), digital signal processor (DSPs), and graphics processing units (GPUs) up to heterogeneous clusters and supercomputers. Its internal computational engine is written in OpenCL and utilizes a variety of advanced numerical methods such as Level set method, Finite Difference, Lattice Boltzmann, and Immersed Boundary. ASL can be used to model various coupled physical and chemical phenomena, especially in the field of Computational Fluid Dynamics. It is distributed under the free GNU Affero General Public License with an optional commercial license.

ADMB or AD Model Builder¹¹ is a free and open-source software suite for nonlinear statistical modeling. It was created by David Fournier and now it is being developed by the ADMB project, a creation of the nonprofit ADMB foundation. The AD in AD Model Builder refers to the automatic differentiation capabilities that come from the AUTODIF Library, a C++ language extension also created by David Fournier, which implements reverse-mode automatic differentiation. A related software package, ADMB-RE, provides additional support for modeling random effects.

Chapel¹² is an emerging parallel language being developed at the Cray Inc. with the goal of addressing this issue and making parallel programming far more productive and generally accessible.

Euler (now Euler Mathematical Toolbox or EuMathT) is a free and open-source numerical software package.¹³ It contains a matrix language, a graphical notebook style interface, and a plot window. Euler is designed for higher level math such as calculus, optimization, and statistics. The software can handle real, complex, and interval numbers, vectors, and matrices. It can produce 2D/3D plots, and uses Maxima for symbolic operations. The software is compatible with Windows. The Unix and Linux versions do not contain a computer algebra subsystem.

FreeFem++ is a PDE solver.¹⁴ It has its own language. FreeFem scripts can solve multiphysics nonlinear systems in 2D and 3D. Problems involving PDE (2d, 3d) from several branches of physics such as fluid–structure interactions require interpolations of data on several meshes and their manipulation within one program. FreeFem++ includes a fast 2^d-tree-based interpolation algorithm and a language for the manipulation of data on multiple meshes. FreeFem++ is written in C++ and the FreeFem++ language is a C++ idiom. It runs on Macs, Windows, and Unix machines. FreeFem++ replaces the older FreeFem and FreeFem+.

FreeMat¹⁵ is a free environment for rapid engineering and scientific prototyping and data processing. It is similar to commercial systems such as MATLAB from MathWorks and IDL from Research Systems, but it is Open Source. FreeMat is available under the GPL license.

The Genius Project Enterprise¹⁶ project management software is designed to adapt to your organization’s business processes, Genius Project delivers a highly flexible and configurable portfolio and project management software allowing tailored feature sets for a wide array of project teams and project types.

Gmsh¹⁷ is a free 3D finite element grid generator with a built-in CAD engine and postprocessor. Its design goal is to provide a fast, light, and user-friendly meshing tool with parametric input and advanced visualization capabilities. Gmsh is built around four modules: (1) geometry, (2) mesh, (3) solver, and (4) postprocessing. The specification of any input to these modules is done either interactively using the graphical user interface or in ASCII text files using Gmsh’s own scripting language.

GNU Octave¹⁸ is a high-level interpreted language, primarily intended for numerical computations. It provides capabilities for the numerical solution of linear and nonlinear problems, and for performing other numerical experiments. It also provides extensive graphics capabilities for data visualization and manipulation. Octave is normally used through its interactive command line interface, but it can also be used to write noninteractive programs. The Octave language is quite similar to MATLAB so that most programs are easily portable. Octave is distributed under the terms of the GNU General Public License.

Julia¹⁹ is a high-level, high-performance dynamic programming language for technical computing with a syntax that is familiar to users of other technical computing environments. It provides a sophisticated compiler, distributed parallel execution, numerical accuracy, and an extensive mathematical function library. Julia’s Base library, largely written in Julia itself, also integrates mature, best-of-breed open-source C and Fortran libraries for linear algebra, random number generation, signal processing, and string processing. In addition, the Julia developer community is contributing a number of external packages through Julia’s built-in package manager at a rapid pace. IJulia, a collaboration between the IPython and Julia communities, provides a powerful browser-based graphical notebook interface to Julia. Massachusetts Institute of Technology (MIT) licensed this software as free and open source.

Maxima²⁰ is a system for the manipulation of symbolic and numerical expressions, including differentiation, integration, Taylor series, Laplace transforms, ordinary differential equations, systems of linear equations, polynomials, sets, lists, vectors, matrices, and tensors. Maxima yields high-precision numerical results by using exact fractions, arbitrary precision integers, and variable-precision floating-point numbers. Maxima can plot functions and data in two and three dimensions. The Maxima source code can be compiled on many systems, including Windows, Linux, and MacOS X. The source code for all systems and precompiled binaries for Windows and Linux are available at the SourceForge file manager.

Maxima is a descendant of Macsyma, the legendary computer algebra system developed in the late 1960s at the MIT. It is the only system based on the ...