Browse Topic: Scale models
Effective thermal management is crucial for vehicles, impacting both passenger comfort and safety, as well as overall energy efficiency. Electric vehicles (EVs) are particularly sensitive to thermal considerations, as customers often experience range anxiety. Improving efficiency not only benefits customers by extending vehicle range and reducing operational costs but also provides manufacturers with a competitive edge and potential revenue growth. Additionally, efficient thermal management contributes to minimizing the environmental impact of the vehicle throughout its lifespan. Digital twins have gained prominence across various industries due to their ability to accelerate development while minimizing testing costs. Some applications have transitioned to comprehensive three-dimensional models, while others employ model reduction techniques or hybrid approaches that combine different modeling methods. The discovery of unknown working mechanisms, more efficient and effective control
This paper presents a novel fully-automatic remeshing procedure, based on the level-set method and Delaunay triangulation, to model three-dimensional boundary problems and generate a new conformal body-fitted mesh. The proposed methodology is applied to long-term in-flight ice accretion, which is characterized by the formation of extremely irregular ice shapes. Since ice accretion is coupled with the aerodynamic flow field, a multi-step procedure is implemented. The total icing exposure time is subdivided into smaller time steps, and at each time step a three-dimensional body-fitted mesh, suitable for the computation of the aerodynamic flow field around the updated geometry, is generated automatically. The methodology proposed can effectively deal with front intersections, as shown with a manufactured example. Numerical simulations over a NACA0012 swept wing both in rime and glaze conditions are compared with the experimentally measured ice shapes from the 1st AIAA Ice Prediction
This paper presents a workflow that allows noise, vibration and harshness (NVH) engineers to objectively predict the passenger compartment noise levels due to structure-borne and radiated noise arising from the motor of an electric powertrain (ePowertrain). The optimized simulation workflow enables transmission, vehicle design engineers and NVH analyst to collaborate and address potential noise concerns well before production of the ePowertrain unit and vehicle. The NVH targets can be cascaded through a series of transfer functions, linking the electromagnetic (EM) excitation from the motor to passenger compartment noise level requirements. The workflow involves the use of Romax Spectrum and Actran software. The structural modelling of the ePowertrain including the vibration response of the ePowertrain is calculated using Romax Spectrum, whilst Actran computes the acoustic radiation around the complete vehicle, and Virtual SEA then covers the calculation to interior and exterior
In recent years, the electric vehicle industry has been booming rapidly to decarbonize the world. One of the major concerns in an electric vehicle is the noise emitted from the electric powertrain system, which affects the driving comfort assistance in electric vehicles. Thus, we have to find the methodology to measure the noise level in an automotive transmission system during the design stage itself. This drives us to develop the methodology on a simple design, having a structural and fluid coupling and then followed by an acoustics analysis. A Transient CFD simulation is performed to generate an excitation source for noise; excitation forces observed in the transient simulation are converted into the frequency domain by performing a fast Fourier transform (FFT). To understand this structural behavior, modal analysis is performed for a simple test model to identify the critical modes. Harmonic excitation sources from CFD fluid coupling are imported to a structural model, replicating
This study consists of a novel approach based on Classical Mechanics to explain the aerodynamic forces on a body in motion relating to a fluid. This new approach does not require the presence of viscosity to generate the forces and is compatible with the Kutta condition. The physical reasoning of the approach is outlined with the introduction of the aerodynamic suction effect of the body. Next, the mathematical expressions and a code that models the physical phenomena are developed. These are applied for the case of a sphere immersed in a moving fluid and then an airfoil. An initial validation of this new approach is performed by a comparison of the theoretical results and the available results of the National Advisory Committee for Aeronautics (NACA) airfoils. This new mathematical approach is especially valid for high Reynolds numbers where viscosity can be neglected. The new codes based on this approach is less complex than other computational fluid dynamics (CFD) approaches based
Accurate fault diagnosis is critical to the safe and efficient operation of lithium-ion battery systems. However, various faults in battery systems are difficult to detect and isolate due to their similar features. This paper proposes a model-based multi-fault diagnosis method to detect and isolate the current, voltage, and temperature sensor faults, short circuit faults, and connection faults in the lithium-ion battery systems. An electro-thermal model with fault information is established and used to construct the structural model. Structural analysis theory is applied to design diagnostic tests sensitive to multiple faults. To improve the accuracy and robustness of residual generation, the adaptive extended Kalman filter is introduced to battery state estimation. The multi-fault detection and isolation are implemented using residual evaluation based on the cumulative sum algorithm. Furthermore, a fault indicator used to distinguish short circuit and connection faults is presented
Current structural design methods for high-speed naval craft rely heavily on empiricism. Though these methods have been employed reliably for a number of years, it is likely that an unknown level of conservatism exists in the prediction of both global and local impact loads to ensure the vessel’s structural design is robust
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