General-purpose Simulation Tool Research Articles

Numerical Simulations in Ultrasonic Guided Wave Analysis for the Design of SHM Systems—Benchmark Study Based on the Open Guided Waves Online Platform Dataset

Structural health monitoring (SHM) strategies based on ultrasonic guided waves are very promising regarding thin-walled lightweight structures. To study the performance of such systems, validated numerical analysis tools have to be used. For that procedure, a benchmark between two numerical methods will be presented. The first promising approach is the elastodynamic finite integration technique (EFIT). Miscellaneous research shows that its capability of capturing wave characteristics and interactions is advanced in various media and structures, including thin-walled composites. The second approach employs conventional shell-type finite elements following the Reissner–Mindlin theory for modelling layered composite structures. The advantage of using such finite element methods (FEM) is their high availability in general purpose simulation tools. As a reference model, the measurement data coming from the Open Guided Waves Project (OGW) was taken into account. The OGW dataset provides the experimental data of ultrasonic guided wave propagation in carbon fiber composite plates with an additional omega stringer. By using this contribution, this experiment was reproduced by simulation. The paper presents the results of a validation and motivates further research, such as in research related to the probability of detection analysis and numerical performance.

Development and application of a user-friendly general-purpose predictive simulation tool for two-dimensional flow analysis

Development and application of a user-friendly general-purpose predictive simulation tool for two-dimensional flow analysis

Versatility or validity: A comprehensive review on simulation of Datacenters powered by Renewable Energy mix

Nowadays, DataCenters powered by Renewable Energy mix (DCRE) appear worldwide. It brings a hot topic on studying how to fully utilize renewable energy and save brown energy. However, for the vast and complex infrastructure, researchers would perform their studies on a DCRE simulator rather than a real-world DCRE. It brings a question: do these simulators have the same functions and result for the same optimization approach? This paper focuses on the question and proposes the versatility and validity models and relationships for these simulators. We use the term ”simulators” broadly, encompassing any general-purpose simulation tools, experiment-purpose simulation approaches, and other simulation works on DCREs. We have reviewed the simulation works for DCRE in the last ten years. After that, we rebut the widespread practice that a simulator has functions for the particular study with an assumed validity. Furthermore, we claim that uniform metrics for both versatility and validity lead to a better simulator. Finally, we back up this claim with comprehensive benchmarking. The experimental results show that the more versatile a simulator is, the better its validity.

Nauticle: A general-purpose particle-based simulation tool

Nauticle is a general-purpose simulation tool for the flexible and highly configurable application of particle-based methods of either discrete or continuum phenomena. The paper introduces a novel approach to the implementation which handles a general formulation composed of user-defined expressions and interaction-laws covering an extensive range of particle-based methods. As a result, Nauticle has three distinct levels for users and developers. At the top level, the Symbolic Form Language (SFL) of Nauticle facilitates the formulation of user-defined numerical models in text-based configuration files. The SFL can be intuitively extended at the intermediate level with new particle methods without tedious recoding or even the knowledge of the bottom level. The paper presents the structure of the underlying general algorithm; then the top two levels are discussed in detail and illustrated by simple application examples. Finally, the efficiency of the code is also tested through a performance benchmark. Program summaryProgram Title: NauticleProgram Files doi:http://dx.doi.org/10.17632/9kxrzr96ww.1Licensing provisions: GNU Lesser General Public License v3Programming language: C++Nature of problem: Construction of a flexible simulation tool for particle methods by multilevel user and developer interface for building almost arbitrary mathematical models – in one, two or three dimensions – through user-defined algebraic and partial differential equations.Solution method: A general formulation of particle methods (schemes) or mathematical models interpretable as a description of relationships between particles by considering them as a set of interaction laws is solved at the bottom level. The simulation case including the definition of the exact form of the equations can be constructed using the proposed Symbolic Form Language at the top level by YAML-documents; hence the solver does not require any programming knowledge or experience. Besides that, at the second level, the Nauticle environment provides an efficient, flexible interface in C++ for the adoption of truly arbitrary new schemes interpreted as the simple extension of the Symbolic Form Language. The collection of particle methods and mathematical models already implemented is: •Gravitational interaction (for n-body problems)•Smoothed Particle Hydrodynamics (SPH)•Discrete Element Method (DEM)•Discrete Vortex Method (DVM)•micro-scale social force model•molecular dynamics based on the Lennard-Jones potential (MD)•Kuramoto synchronizationRestrictions: The present version of Nauticle does not involve implicit schemes.Additional comments: The automated installation of the current Nauticle release requires Advanced Packaging Tool (APT) or Homebrew. The code has been tested under Ubuntu 16.04. and MacOS 10.12. and 10.14.The Nauticle source code is available at www.bitbucket.org/nauticleproject

Finite Element Analysis of Square RC Columns Confined by Different Configurations of Transverse Reinforcement

Introduction:Square reinforced concrete (RC) columns with the confinement effect of transverse reinforcement perform well in ductility and have been used widely in RC structures. Its behavior is the classic topic of anti-seismic and anti-collapse analysis of RC structures. With the advancement of the finite element (FE) analysis technology, the general-purpose simulation tools such as ABAQUS and ANSYS have been universally used to analyze the behavior of structures and members, where the material constitutive model is a key problem in the analysis.Methods:In this study, a new uniaxial compressive stress-strain curve of the confined concrete considering confinement effect of transverse reinforcement in square RC columns was proposed for the concrete damaged plasticity model in ABAQUS to solve the problem that there is no proper uniaxial compressive stress-strain curve for the concrete damaged plasticity model to describe the behavior of concrete confined by transverse reinforcement. Based on the proposed stress-strain relationship, a FE model was developed to analyze the behaviour of laterally confined RC columns under concentric loading.Results:The finite element model is able to predict the response of the confined RC columns from different experiments with reasonable accuracy. Finally, a parametric study was conducted in order to evaluate the effect of confinement reinforcement configuration on the behavior of core concrete in square section.

Eurobalise-Train communication modelling to assess interferences in railway control signalling systems

The evolution of the railway sector depends, to a great extent, on the deployment of advanced railway signalling systems. These signalling systems are based on communication architectures that must cope with complex electromagnetical environments. This paper is outlined in the context of developing the necessary tools to allow the quick deployment of these signalling systems by contributing to an easier analysis of their behaviour under the effect of electromagnetical interferences. Specifically, this paper presents the modelling of the Eurobalise-train communication flow in a general purpose simulation tool. It is critical to guarantee this communication link since any lack of communication may lead to a stop of the train and availability problems. In order to model precisely this communication link we used real measurements done in a laboratory equipped with elements defined in the suitable subsets. Through the simulation study carried out, we obtained performance indicators of the physical layer such as the received power, SNR and BER. The modelling presented in this paper is a required step to be able to provide quality of service indicators related to perturbed scenarios.

Educational approach to transient analysis of electric circuits by simulating equations

When studying an electric circuit, one can describe the circuit using equations. The equations can be coded into a computer program and iterated with fixed time step through time of interest, which generates simulation results. A specific methodology is needed for the purpose. The methodology of simulation of equations is developed and presented. Using this approach there is no black box (a general-purpose simulation tool) between the student or an engineer who is simulating the circuit, and the circuit itself. The use of “black boxes” – general-purpose simulators – is of great value when optimising circuits, but they can leave “black holes” when it is about understanding circuit principles and/or exploring new circuit ideas. Simulating equations leaves no space for “simulation noise”. The circuit is DC-wise analysed at sequential moments in time. Equations, which describe circuit components that store energy (capacitors and inductors), connect in time sequential DC analyses. The simulation of equations adds to the understanding of existing circuits and it has potential in the creation of new circuits. Time- and/or signal- and/or environment-dependent devices can be easily included in the simulation of equations. Test cases show a perfect match between simulated and known results for the analysed circuits. Programming efforts for the simulation of equations are at a manageable level for even a moderately proficient programmer.

Insight Maker: A general-purpose tool for web-based modeling & simulation

A web-based, general-purpose simulation and modeling tool is presented in this paper. The tool, Insight Maker, has been designed to make modeling and simulation accessible to a wider audience of users. Insight Maker integrates three general modeling approaches – System Dynamics, Agent-Based Modeling, and imperative programming – in a unified modeling framework. The environment provides a graphical model construction interface that is implemented purely in client-side code that runs on users’ machines. Advanced features, such as model scripting and an optimization tool, are also described. Insight Maker, under development for several years, has gained significant adoption with currently more than 20,000 registered users. In addition to detailing the tool and its guiding philosophy, this first paper on Insight Maker describes lessons learned from the development of a complex web-based simulation and modeling tool.

Rule-based modeling: a computational approach for studying biomolecular site dynamics in cell signaling systems.

Rule-based modeling was developed to address the limitations of traditional approaches for modeling chemical kinetics in cell signaling systems. These systems consist of multiple interacting biomolecules (e.g., proteins), which themselves consist of multiple parts (e.g., domains, linear motifs, and sites of phosphorylation). Consequently, biomolecules that mediate information processing generally have the potential to interact in multiple ways, with the number of possible complexes and posttranslational modification states tending to grow exponentially with the number of binary interactions considered. As a result, only large reaction networks capture all possible consequences of the molecular interactions that occur in a cell signaling system, which is problematic because traditional modeling approaches for chemical kinetics (e.g., ordinary differential equations) require explicit network specification. This problem is circumvented through representation of interactions in terms of local rules. With this approach, network specification is implicit and model specification is concise. Concise representation results in a coarse graining of chemical kinetics, which is introduced because all reactions implied by a rule inherit the rate law associated with that rule. Coarse graining can be appropriate if interactions are modular, and the coarseness of a model can be adjusted as needed. Rules can be specified using specialized model-specification languages, and recently developed tools designed for specification of rule-based models allow one to leverage powerful software engineering capabilities. A rule-based model comprises a set of rules, which can be processed by general-purpose simulation and analysis tools to achieve different objectives (e.g., to perform either a deterministic or stochastic simulation).

Hybrid models and biological model reduction with PyDSTool.

The PyDSTool software environment is designed to develop, simulate, and analyze dynamical systems models, particularly for biological applications. Unlike the engineering application focus and graphical specification environments of most general purpose simulation tools, PyDSTool provides a programmatic environment well suited to exploratory data- and hypothesis-driven biological modeling problems. In this work, we show how the environment facilitates the application of hybrid dynamical modeling to the reverse engineering of complex biophysical dynamics; in this case, of an excitable membrane. The example demonstrates how the software provides novel tools that support the inference and validation of mechanistic hypotheses and the inclusion of data constraints in both quantitative and qualitative ways. The biophysical application is broadly relevant to models in the biosciences. The open source and platform-independent PyDSTool package is freely available under the BSD license from http://sourceforge.net/projects/pydstool/. The hosting service provides links to documentation and online forums for user support.

Simulation of air-to-refrigerant fin-and-tube heat exchanger with CFD-based air propagation

A new model for simulating air-to-refrigerant fin-and-tube heat exchangers with computational fluid dynamics (CFD)-based air propagation is introduced. This model is based on a segment-by-segment approach and is developed to be a general purpose and flexible simulation tool. The model superimposes a CFD mesh on the heat exchanger model’s geometric grid, interprets the CFD results, and processes them to generate the air propagation path through the heat exchanger. The model is capable of accounting for air flow maldistribution and other complex flow patterns including recirculation zones within the heat exchanger, as well as, entrainment of exit flow into the heat exchanger, using both two-dimensional (2D) and three-dimensional (3D) CFD results. The modeling results show that the overall predicted heat load using 3D-CFD simulation results agrees within ±4% of the experimental data, without employing any multipliers on air side correlations.

M uM ax: A new high-performance micromagnetic simulation tool

We present M uM ax, a general-purpose micromagnetic simulation tool running on graphical processing units (GPUs). M uM ax is designed for high-performance computations and specifically targets large simulations. In that case speedups of over a factor 100 × can be obtained compared to the CPU-based OOMMF program developed at NIST. M uM ax aims to be general and broadly applicable. It solves the classical Landau–Lifshitz equation taking into account the magnetostatic, exchange and anisotropy interactions, thermal effects and spin-transfer torque. Periodic boundary conditions can optionally be imposed. A spatial discretization using finite differences in two or three dimensions can be employed. M uM ax is publicly available as open-source software. It can thus be freely used and extended by community. Due to its high computational performance, M uM ax should open up the possibility of running extensive simulations that would be nearly inaccessible with typical CPU-based simulators.

Selection of the simulation software for the management of the operations at an international airport

A new airport in Spain is looking for tools that will help not only with the scheduling of resources but also with their real time control during normal operations. The selection process of the software has been based on the study of the capabilities of the commercial and general-purpose simulation and visualization tools available as well as on the quantification of user requirements and the development of trial versions. Analytical Hierarchy Process has been used to choose the platform, which is composed of a simulation model developed in JAVA and two visualization screens, one in JAVA and the other in Visual Basic.

Computational modeling and simulation of complex systems in bio-electronics

In this article, we discuss the mathematical and computational framework required to develop a general-purpose simulation tool for bio-electronic applications. Electrochemical and fluid-mechanical transport of substances, chemical reactions and electrical transduction of biological signals are described through the coupled use of systems of partial and ordinary differential equations (PDEs and ODEs). Functional iteration techniques for system decoupling and mixed-hybridized finite element discretization methods are proposed and validated in the simulation of realistic problems in Electrophysiology and Biochemistry.

Incorporating ObjectStab library and fuzzy logic toolbox for design of power system damping controller

AbstractObjectStab is a general purpose simulation tool for power system stability studies developed by Modelica which is an object‐oriented modeling language. It provides enough modeling flexibility to allow addition or modification of new power system components. This article describes an incorporated use of ObjectStab library and fuzzy logic toolbox in Matlab/Simulink to enhance the application of this library into fuzzy control design environment. The example provided here is the modeling of the static synchronous series compensator (SSSC) which is the new device developed in the ObjectStab. In addition, the interface of ObjectStab with Matlab/Simulink for an SSSC damping controller design by fuzzy logic toolbox is explained step by step. In fuzzy control design, a simple approach to extract membership functions and fuzzy logic control rules based on observed signals is presented. Simulation studies in a two‐area four‐generator power system confirm the effectiveness of the fuzzy controller of SSSC designed by the incorporated use of ObjectStab and fuzzy logic toolbox. © 2008 Wiley Periodicals, Inc. Comput Appl Eng Educ 16: 243–255, 2008; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae20126

Agent-based simulation of electricity markets: a survey of tools

Agent-based simulation has been a popular technique in modeling and analyzing electricity markets in recent years. The main objective of this paper is to study existing agent-based simulation packages for electricity markets. We first provide an overview of electricity markets and briefly introduce the agent-based simulation technique. We then investigate several general-purpose agent-based simulation tools. Next, we review four popular agent-based simulation packages developed for electricity markets and several agent-based simulation models reported in the literature. We compare all the reviewed packages and models and identify their common features and design issues. Based on the study, we describe an agent-based simulation framework for electricity markets to facilitate the development of future models for electricity markets.

Data-driven simulation of the supply-chain—Insights from the aerospace sector

With the increasing complexity of supply chains in aerospace manufacturing, simulation has become a powerful tool to assess performance. Conventional simulation models are constructed by experts, limiting their usefulness for non-experts. Here, the concept of data-driven simulation is used, where the simulation model is constructed automatically using input data from company IT systems. The paper describes the concept and operation of a supply-chain model builder that has been developed. An example model is provided from the civil aerospace sector. The study shows that data-driven simulation can be useful to support the design and improvement of supply chains. The nature of the conceptual model, model verification and validation in data-driven simulations are discussed. Data-driven simulation is not a replacement for general-purpose simulation tools, but an adjunct valuable in certain circumstances. It can allow a variety of scenarios to be explored relatively quickly without a high level of simulation expertise.

CoilDesigner: a general-purpose simulation and design tool for air-to-refrigerant heat exchangers

A simulation and design tool to improve effectiveness and efficiency in design, and analysis of air to refrigerant heat exchangers, CoilDesigner, is introduced. A network viewpoint was adopted to establish the general-purpose solver and allow for analysis of arbitrary tube circuitry and mal-distribution of fluid flow inside the tube circuits. A segment-by-segment approach within each tube was implemented, to account for two-dimensional non-uniformity of air distribution across the heat exchanger, and heterogeneous refrigerant flow patterns through a tube. Coupled heat exchangers with multiple fluids inside different subsets of tubes can be modeled and analyzed simultaneously. A further sub-dividing-segment model was developed in order to address the significant change of properties and heat transfer coefficients in the single-phase and two-phase regime when a segment experiences flow regime change. Object-oriented programming techniques were applied in developing the program to facilitate a modular, highly flexible and customizable design platform and in building a graphic user-friendly interface. A wide variety of working fluids and correlations of heat transfer and pressure drop are available at the user's choice. The model prediction with CoilDesigner was verified against experimentally determined data collected from a number of sources.

Computer-aided small-signal analysis based on impulse response of DC/DC switching power converters

The paper describes a method for automated small-signal frequency response analysis based on transient response obtained using a general-purpose simulation tool such as simulation program with integrated circuit emphasis (SPICE). The method is based on using the simulation tool to evaluate the converter impulse response. The main advantage of the proposed method as a design verification tool is that frequency responses can be generated efficiently for any converter configuration and any model complexity supported by the general-purpose simulator. Application examples are included to demonstrate very good correlation between the generated responses and experimental data, and to compare the results with predictions of approximate analytical methods. In particular, the method is applied to investigate high-frequency dynamics of pulse width modulation (PWM) converters operating in discontinuous conduction mode, and the results are used to compare and validate several existing analytical modeling approaches.

General-Purpose Systems for Effective Construction Simulation

This paper examines the characteristics of discrete-event simulation systems in terms of their application breadth (general or special purpose), modeling paradigm (process interaction versus activity scanning), and flexibility (programmable or not). Several construction simulation systems are examined with primary emphasis on CYCLONE and STROBOSCOPE as representatives of the wide range of tools that are currently available. CYCLONE is a well-established, widely used, and simple system that is easy to learn and effective for modeling many simple construction operations. STROBOSCOPE is a programmable and extensible simulation system designed for modeling complex construction operations in detail and for the development of special-purpose simulation tools. The characteristics of these systems, as well as other recent developments, illustrate that an effective general-purpose simulation tool for construction is in essence one based on extended forms of activity cycle diagrams and the activity scanning modeling paradigm. As explained through several examples, these representations are indeed the most convenient and intuitive for construction simulation systems. Furthermore, the programmability of such a system is the principal factor that determines its power, flexibility, and ease of learning and use.