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Multiphysics 1

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08:35
conference time (CEST, Berlin)
Enhanced Correlation for off Highway Vehicle Wheel Loads Using an Integrated Multiphysics Multibody Dynamics Simulation Model
26/10/2021 08:35 conference time (CEST, Berlin)
Room: L
R. Udasi (John Deere India Pvt Ltd - Pune, IND); A. Shah (John Deere, USA)
R. Udasi (John Deere India Pvt Ltd - Pune, IND); A. Shah (John Deere, USA)
Wheel loads are one of the most sought-after inputs for durability evaluation of chassis and suspension system in off-highway agricultural vehicles. Collecting wheel loads through physical test is cumbersome in terms of time, cost, and efforts. Instead, usage of a simulation-based approach to predict accurate wheel loads during early phase of product development has lot of usefulness and benefits. This paper will talk in detail about using an Integrated Multiphysics Multibody Dynamics Simulation Model with Hydrostatic Transmission and Embedded Software for off highway vehicle which is also called CommandDrive powertrain that consists of a single pump which sends flow to all four variable displacement motors separately to drive all four wheels. If one or more wheels loose traction, the system will adjust to slow the wheels that are slipping and direct more flow to the remaining wheels to retain all wheel drive. In this paper, a comparison of simple to advanced level of simulation integrated model for predicting wheel loads on a Self-Propelled Sprayer during a turning operation will be presented. During a turn, rpm of inner wheel will be less than the rpm of outer wheel. This is because the inner wheel travels less distance as compared to outer wheel. To capture the turning phenomenon accurately, different fidelity levels of integrated models including Hydrostatic Transmission or Embedded Software and their pros and cons will be discussed as below: 1. All wheel’s same speed input driven vehicle level Rigid MBD model – Traditional Approach 2. Vehicle speed input driven Hydrostatic transmission equivalent Mechanical drivetrain full vehicle model 3. Hydrostatic transmission integrated vehicle Multiphysics model 4. Integrated Multiphysics Multibody Dynamics Simulation Vehicle Model with Hydrostatic Transmission and Embedded Software The effect and significance of Multiphysics integrated simulation model’s increased fidelity would then illustrate enhanced wheel loads correlation with respect to test data and show importance of integrated modeling approach.
Powertrain, Embedded Software, Integrated, Multiphysics, Multibody Dynamics Model, Dynamic System Modeling, Hydrostatic Transmission, Wheel loads, Enhanced Correlation, Off highway Agricultural vehicle
08:55
conference time (CEST, Berlin)
Smart Automatic Configurator for Fast and Robust Fluid Structure Interaction Co-Simulations
26/10/2021 08:55 conference time (CEST, Berlin)
Room: L
H. Arjmandi (Fraunhofer SCAI, DEU); D. C. Padmanabhan (Bonn-Rhein-Sieg University of Applied Sciences, DEU)
H. Arjmandi (Fraunhofer SCAI, DEU); D. C. Padmanabhan (Bonn-Rhein-Sieg University of Applied Sciences, DEU)
Multiphysics simulation is the study of the interaction between multiple physical domains. An example of multiphysics simulation is Fluid-Structure Interaction (FSI). In FSI, a deformable solid structure interacts with a compressible or incompressible fluid flow. The fluid and solid domains are governed by their own principles using conservation or constitutive laws. Each domain solves its own equations separately. The domains are coupled via common boundaries by exchanging pressure and displacement of the common boundary. In this study, the coupling tool Mesh-based parallel Code Coupling Interface (MpCCI) is used to solve FSI problems. Being an integral part of various academic and industrial applications, the coupling tool is highly parameterized. The process of manually tuning the optimal parameter configuration is a tedious task given the number of parameters, types of parameters, domain expertise of the users, and the substantial time taken to solve a single simulation instance. The different choices of MpCCI parameters affect the accuracy, robustness and run-time of the co-simulations. MpCCI configurator tool is used to set parameters of MpCCI automatically employing both optimization and machine learning methods. The algorithm behind this tool consists of optimization, normalization, training and prediction. However, there are some challenges to improve the performance of the tool. In order to tune the tool, the machine learning features should be selected wisely for the training and prediction steps. Therefore, the sensitivity of the features is analysed and the most important ones are considered to be the machine learning features for the tool. Furthermore, some pre-processing methods are implemented to enhance the efficiency of training and prediction. In this work, it is investigated how effective the tool is for industrial FSI applications. The run-time obtained by the tool is compared to the run-time corresponding to the default configuration and to the actual optimal run-time as well. Additionally, it is checked whether the suggested configuration converges to accurate results.
Automatic Algorithm Configuration, Machine Learning, Optimization, Fluid-Structure Interaction, MpCCI
09:15
conference time (CEST, Berlin)
A Model Based Approach for a Multiphysics Optimization of an Airborne Radome
26/10/2021 09:15 conference time (CEST, Berlin)
Room: L
A. Bhattacharya, M. Krause, Y. Shestakovskiy, T. Bernarding (Dassault Systèmes, DEU, ); R, Valecha (Dassault Systèmes, IND); C. Karch (Airbus Defence and Space, DEU)
A. Bhattacharya, M. Krause, Y. Shestakovskiy, T. Bernarding (Dassault Systèmes, DEU, ); R, Valecha (Dassault Systèmes, IND); C. Karch (Airbus Defence and Space, DEU)
Airborne radomes are critical for protecting the antenna from the environment. However, the presence of radomes can affect the performance of the antenna systems and therefore it is essential to consider the radome while designing the antenna system. A well-designed radome is transparent to the electromagnetic waves within the operating frequency band of the antenna while satisfying the structural and aerodynamic requirements. In this paper, a multidisciplinary design optimization workflow is proposed for designing airborne radomes. The electromagnetic performance and the mechanical response of the radome are considered simultaneously while optimizing the material properties and geometrical parameters of the radome wall structure. Aerodynamic forces on the radome surface are extracted from a steady-state Reynolds-Averaged Navier-Stokes computational fluid dynamics analysis and mapped onto the structural simulation in a one-way coupling. The structural integrity of the radome is simulated by applying the aerodynamic pressure from the CFD analysis as a static load in a linear static analysis as well as a buckling analysis. Additionally, an explicit bird strike analysis is performed using the smoothed particle hydrodynamics (SPH) method in order to prevent structure failure in an event of a bird strike. A hybrid simulation approach is utilized in order to model the electromagnetic interaction between the antenna system and the radome based on a 3D full-wave analysis technique as well as Physical Optics. To validate the design approach a multi-layered sandwich radome protecting a weather radar antenna operating at X-band (9.3 GHz) is studied. The antenna and the radome are situated at the nose of a regional jet type commercial aircraft. A slotted waveguide antenna array is used to achieve the scanning behaviour. The aerodynamic forces on the radome surface were computed at typical cruise flight conditions to provide the input for calculating the resulting stress under the aerodynamic loading. The thickness and the stacking sequences of the different layers of the radome are optimized with the objective to maximize the transmission coefficient subjected to the constraining buckling safety factor. Additionally, the maximum structural damage in the event of a high velocity bird impact is simulated to ensure that no loss of structural integrity of the radome occurs with the optimal design parameters. The lighting protection strips on the radome have also been included in the study to investigate the impact of the solid and segmented strips on the radiation performance of the antenna. The model based engineering approach offers an efficient workflow to automate the multiphysics analysis of the radome resulting in optimal designs for electromagnetic and mechanical performance of radomes. This approach enables early stage design validation of radomes and accurate prediction of antenna behaviour with the radome, thus reducing the amount for physical prototyping and therefore design costs.
MBSE, radome, optimization, multiphysics
09:35
conference time (CEST, Berlin)
Coupled Simulation of Flow-induced Deformations of Filter Media
26/10/2021 09:35 conference time (CEST, Berlin)
Room: L
R. Kirsch (Fraunhofer ITWM, DEU); S. Antonyuk, V. Puderbach, O. Lykhachova (TU Kaiserslautern, DEU)
R. Kirsch (Fraunhofer ITWM, DEU); S. Antonyuk, V. Puderbach, O. Lykhachova (TU Kaiserslautern, DEU)
Fluid flowing through filter materials causes deformations which can lead to effects like pleat collapse, pleat crowding etc. Therefore, simulation models assuming “rigid” filter media are not capable of predicting such phenomena. Modelling and simulation of the interaction between fluid flow and solid structures (FSI) has been subject to extensive research for decades. However, a straightforward application of these methods to the case of porous materials is not suitable, because the fluid flow enters the material and therefore, the transmission of forces is not limited to the media surface. Compared to FSI, Fluid-Porous-Structure Interaction (FPSI) is a quite new and challenging area of research. The talk presents the joint research conducted at Technische Universität Kaiserslautern and Fraunhofer ITWM to increase the understanding and improve simulation methods for the deformation of filter media caused by stationary liquid flow (e.g. fuel and oil filters). As a starting point, flow resistivity and structural mechanical properties (tensile, compression and bending tests) were measured in dry condition for a range of filter media. In order to clarify, to which extent these material data can be applied under flow conditions, a specialized test bench is developed which allows for recording flow rate, differential pressure and the deformation of the filter medium by optical measurements. The experimental findings are used both to identify the material models for the media and to validate the simulations. Here, Computational Fluid Dynamics (CFD) is coupled with structural mechanics simulations. The coupling from CFD to structural mechanics uses the fact that the gradient of the fluid pressure is a volumetric force density acting on the interior of the filter material. The corresponding deformation is used to update the shape of the filter material and the flow is recomputed. This procedure is repeated until a steady state for the media shape is reached. If the simulations of flow and structural mechanics use a common grid, the displacement field provides the update the media shape. However, if the two simulations codes operate on different grids, suitable methods to transfer the required data (pressure gradient, shape) back and forth are required. The results of this work are presented and discussed as well as the ongoing and future developments.
Coupled simulation, Fluid-Porous-Structure Interaction, CFD, FEA
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