Linköping Electronic Conference Proceedings
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Input Smoothing for Faster Co-Simulation using FMI
Full text linkWe present two technologies for speeding up co-simulationsunder the FMI standards. By smoothing the input signalsinside each FMU, the internal integrator may avoidre-initialization. This can significantly reduce the numberof model and Jacobian evaluations. To further help theintegrator we also propose a predictor compensationtechnique tailored to the input smoother. The main benefitof our technologies is the ease-of-use, requiring no modelmanipulations, nor any special co-simulation masteralgorithms. The technologies are implemented inDymola~2025x and validated with both an academic mechanicalmodel as well as thermo-fluid examples where we can observeperformance gains with factor up to 100, and often around5-10. One of these thermo-fluid examples is used in the\emph{OpenSCALING} research project to generate trainingdata for constructing surrogate models, for which the inputsmoothing is especially important to speed up the datasetcreation
Race Car Braking System Thermal Model for Real Time Use in a Driving Simulator
Full text linkOverall vehicle performance optimization is the main targetin race car and road hypercar development. Considering thecomplexity of current vehicles, a holistic approach toanalyse the interaction of vehicle dynamics, powertraincooling system dynamics, brake cooling and human drivers inthe same simulation can be vital to maximizing the overallperformance (Bouvy et al, 2012). This article is acontinuation of a previous article written by Dallara andClaytex (“Race Car Cooling System Model for Real Time usein a Driving Simulator”, Stellato et al, 2023). Theprevious collaboration describes the implementation of a 1Dcooling system model integrated with a vehicle multibodymodel to be used in the Dallara dynamic driving simulatorwith human drivers (Figure 1).This collaboration has continued into a new phase, whereDallara has developed a model to optimize the brake coolingof its vehicles, with Claytex’s VeSyMA suite use for theauxiliary vehicle systems and code compilation. The modelhas been validated through comparison with real data of anexisting vehicle, showing an acceptable accuracy to size arace car braking system and for a refined assessment of theglobal vehicle performance on the driving simulator
Dynamic Simulation of Off-Grid Energy Island with Wind-PV-Storage Hydrogen Production
Full text linkThis study proposes a novel discrete-solving algorithmimplemented on the MWORKS.Sysplorer platform for powerelectronics simulation, addressing transient stabilitychallenges in multi-energy integrated systems with highrenewable energy penetration. For an offshore energyisland, detailed component models including direct-drivewind turbines, photovoltaics, battery energy storage, andalkaline electrolyzers are developed and integrated into astandalone DC system. The energy storage system controlsbus voltage to enable constant-power operation ofelectrolyzers. The implemented discrete algorithm providescritical multi-timescale simulation capabilities, advancingthe planning and construction of offshore energy islandprojects
A Study on the Methodology to Develop Virtual Drive Environment for Autonomous Driving Evaluation
Full text linkIt takes many hours and restrictions once AD(Autonomous Driving) evaluation based on real tests. This paper presents a methodology for development of virtual driving environment that can replace the real vehicle test. When developing a virtual driving environment, it is important to develop the same virtual element model (Road, Vehicle model, etc.) as the real world. So the high-occupancy BRT (Bus Rapid Transit) bus route in Cheongna zone was modelled using the MMS(Mobile Mapping System) as the openDRIVE format which is the ASAM(Association for Standardization of Automation and Measuring Systems) road standard. In addition, we develop a vehicle model that simulates the dynamic performance of BRT based on Modelica language. Finally, we develop an interface module that integrates the virtual environment, the vehicle model, and the driver model. In conclusion, this paper present virtual test drive platform for AD Evaluation
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Full text linkSimulation model for an amine-based CO2 capture rig
Full text linkThe amine-based CO2 capture rig at USN in Porsgrunn has been operating since 2007. In this study, the main aim was to develop predictive models in Aspen HYSYS and Aspen Plus for the CO2 test rig. The models accuracy were verified by comparing different test scenarios with results from the models. Aspen HYSYS and Aspen Plus have simulated eleven scenarios (test series) with varying process parameters. In Aspen HYSYS, Murphree efficiencies (stage efficiences) were fitted, and in Aspen Plus two approaches were used, fitting the interfacial area or the holdup factor to minimize the deviation between the model and experimental data. The Aspen HYSYS model with the fitted Murphree efficiencies (from top to bottom 0.11, 0.1, 0.09 and 0.07) predicted seven scenarios with an average deviation of 12-24 % from experimental data. In the Aspen Plus rate-based model with interfacial area fitted, most of the scenarios were predicted by a model with correlation Brf-85 (mass transfer), Brf-85 (heat transfer) and an interfacial área factor of 0.5. Minimum and maximum deviations for different scenarios were 2.1 and 9 %. In the approach with fitting of the holdup factor, the Brf-92 holdup method with a holdup factor of 0.5 gave the best fit, resulting in an average deviation of 1.4-9 % from the test results across all scenarios
Physical simulation of heat-affected zones in a weld metal used with 500 MPa offshore steel
Full text linkOffshore steels are designed for high strength and toughness to endure extreme offshore and marine conditions. Welding thick steel sections often requires multiple passes, affecting the microstructures of previous passes due to thermal cycles. These heat-affected zones (HAZ) in the weld metal are less studied than those in the base metal. Real welding HAZs are narrow and challenging to study. Physical simulation can create various HAZs on a larger scale for microstructural and mechanical characterization, allowing easy study of different welding methods and parameters.This study aimed to produce coarse-grained (CGHAZ-W), intercritical (ICHAZ-W), and intercritically reheated HAZs (ICCGHAZ-W) in weld metal using physical simulation. The submerged arc welding (SAW) method was used to create the original weld. HAZs with two cooling times (t8/5 = 5 and 30 s) were simulated using the Gleeble 3500 thermomechanical simulator. Microstructures were analyzed with a Zeiss Sigma field emission scanning electron microscope. Results showed the original weld metal had acicular ferrite nucleated on oxide inclusions, and thermal cycles caused distinct microstructural changes in each simulation variant. Physical simulation microstructures were supported by numerical simulation results from JMatPro software
Kinetic modelling and simulation of bioanode and biocathode in a bioelectrochemical cell for carbon dioxide reduction
Full text linkBioelectrochemical systems (BESs) have garnered extensive research attention for their biosynthesis and environmental remediation applications. One of the challenges to upscaling BES for carbon dioxide (CO2) methanation is energy-efficient process development. Investigations are ongoing to determine the relationship between the yield of electroactive microorganisms, the key candidates for electrochemical reactions with external electricity input. Consequently, simulating processes, particularly with biocathode for biosynthesis and bioanode for remediation, gives crucial insights for designing efficient BESs. The framework for establishing Nernst-Monod equations for modeling BES, starts from bioanode, where anode respiring bacteria (ARB) oxidize organic carbon compounds to CO2, and generate the proton (H+). In this work, kinetic modeling was applied to calculate the biomass yield of ARBs corresponding to the applied anodic voltage. The generated CO2 and H+ from the anode determined the biomass yield of electroactive methanogens and acetogens on the cathode. Two biofilm models were established for anodic and cathodic biofilm growth in the Aquasim simulation tool. Results showed that the concentration of organic carbon compound (acetate) available for ARB, had a significant impact on the biofilm thickness and biomass concentration on the biofilm, especially at +0.3 V. The optimum anode voltage which released the highest CO2 and H+, was +0.3 V. The anodic and cathodic biofilm thickness reached 3 mm and 55 µm, respectively, at +0.3 V and 10 g.L-1 acetate input to the anode chamber. Moreover, methanogens surpassed acetogens on the biocathode for CO2 reduction to methane rather than acetate. In addition, acetate consumption rate by ARB at anode was remarkably faster than acetate production at cathode
The Application and Advantages of a Generic Component-Based SI/CI Engine Model with VVA Compatibility
Full text linkMost engine models are developed for control purposes and, in some cases, hard coded with a single engine type usage in mind. This is a problem since a new model is also needed when new engines are developed, as it usually takes less time than changing or modifying the old one. To facilitate a more rapid development process, there is a desire to have control-oriented models that can be adapted to new types of hardware with ease while at the same time providing fundamental insights into the physics of the engine that limit the control performance. These objectives are fulfilled by creating an open-source mean value MATLAB/Simulink model, a generic engine model with parametrization and compatibility with both VVT/VVA and SI/CI combustion.The main idea is to build on a component-based structure where the components are designed to be reused for similar processes. The engine model models the air filter, intercooler, and exhaust system components as incompressible flow restrictions. Bypass, throttle, intake/exhaust valves, and wastegate are modeled as compressible flow restrictions. Adiabatic control volumes are placed between each component to keep track of masses, pressures, and temperatures. The few remaining components are modeled separately, with unique functions for each model. As a concept demonstration of the generality of the approach, two engines, a 6-cylinder 12.7-liter Scania diesel engine and a 4-cylinder 2.0-liter Volvo petrol engine, are used as case studies where the generic simulation platform is parameterized and validated against experimental data for both engines
Objectively Defined Intended Uses, a Prerequisite to Efficient MBSE
Full text linkThis article proposes a method for improved model verification within Large-Scale Simulators (LSS). The approach relies on machine-interoperable traceability of model verification information, such as model Operational Domains (ODs). This enables automated evaluation of model relevance and facilitates the combination of models for a broader evaluation of credible simulation results. The paper introduces a proof-of-concept testbed for verification of black-box models against model requirements. Furthermore, the results also include a proposal for a machine-readable format to capture model requirement Verification & Validation (V&V) results, along with the resulting model and updated model OD information