Multiphysics Design Research Articles

Multiphysical design for optimised ventilation and noise attenuation in ducts: an approach using metamaterials

Noise generation and propagation through mechanical ventilation and air conditioning (MVAC) ducts have been increasingly investigated since commercial solutions allow sensible noise attenuation while reducing the duct section. So, a commercial silencer forces the MVAC power to rise to overcome the flow resistance, increasing the noise source. For this reason, this study focuses on soundproofing ventilation ducts through acoustic metamaterials with no inner duct section decreasing. A crucial part of this study falls into the multiphysical interaction between acoustics and fluid dynamics, which is a phenomenon that may result in a challenging analytical model. In conditions of flowing motion, the wave vector has been modelled according to the Lighthill model: the component of the velocity rotor potential becomes significant, influencing the soundproofing performance due to the metamaterial placed at the edge of the inner surface of the duct. FEM analysis helped design a series of samples which then have been tested experimentally in static conditions. Once the numerical method is calibrated, further multiphysical numerical analysis are used to implement the sound insulation properties of the metamaterial-based filter through dynamic flow conditions. Guidelines for multiphysical setup for wave-based simulation are drawn, and preliminary experimental results are presented.

6 MV X-band linear accelerator for stereotactic body radiation therapy

This paper presents the development process of a high-dose X-band linear accelerator (LINAC) for radiotherapy machines, specifically focusing on stereotactic body radiation therapy (SBRT). The development process includes a multi-physics design, approach for the radio frequency cavity in the LINAC, with an emphasis on minimizing beam size and maximizing shunt impedance of the LINAC. Commissioning tests were conducted to evaluate the performance of the LINAC, which involved measurements of beam energy, beam size, beam current, and X-ray dose rate.

Thermal analysis of 4-phase 8/6 SRM for EV application

This article provides a comprehensive analysis of the thermal characteristics of a 4-phase 8/6 switching reluctance motor (SRM) designed for use in an e-rickshaw (3-wheeler) application. The determination of core and copper losses is achieved through electromagnetic analysis using Finite Element Analysis (FEA). The analysis is conducted via MOTORCAD, a multiphysics design software. This work includes the examination of both static and transient temperature conditions. Static analysis entails the estimation of losses by taking into account the motor's maximum current and operating the motor under steady-state conditions. Transient analysis involves the examination of two separate scenarios. One possesses a simple transient characteristic, while the other possesses a distinct duty cycle. The losses obtained from the electromagnetic analysis are used as the input for the simple transient thermal analysis. During transient analysis involving the duty cycle, losses are assigned to certain operating conditions, such as changes in the operating speed of the motor. This study employs the Lumped Parameter Thermal Network (LPTN), as well as 3D and 2D FEA techniques to conduct thermal analysis. The findings were compared and subsequently given in the article. The findings produced from the LPTN and 3D FEA approaches demonstrate a strong correlation. The motor's maximum temperature is limited to 180 °C. The findings indicate that the highest temperature, both under static and transient conditions, is below the maximum attainable value.

Metaheuristic aided structural topology optimization method for heat sink design with low electromagnetic interference

This study investigates the application of the Metaheuristic Aided Structural Topology Optimization (MASTO) method as a novel approach to address the multiphysics design challenge of creating a heat sink with both high heat conductivity and minimal Electromagnetic Interference (EMI). A distinctive 2D layout with elongated fins is examined for electromagnetic traits, highlighting resonance-related EMI concerns. MASTO proves to be a valuable tool for navigating the complex design space, yielding thoughtfully optimized solutions that harmonize efficient heat dissipation with effective EMI control. By merging simulation findings with practical observations, this study underscores the potential of the MASTO method in achieving effective designs for intricate multiphysics optimization problems. Specifically, the method's capacity to address the complex interplay of heat transfer with convection and the suppression of electromagnetic emissions is showcased. Moreover, the study demonstrates the feasibility of translating these solutions into tangible outcomes through manufacturing processes.

A Multi-Physics Design Approach for Electromagnetic and Stress Performance Improvement in an Interior Permanent Magnet Motor

<div>Electric motors constitute a critical component of an electric vehicle powertrain. An improved motor design can help improve the overall performance of the drivetrain of an electric vehicle making it more compact and power dense. In this article, the electromagnetic torque output of a double V-shaped traction IPMSM is maximized by geometry optimization, while considering overall material cost minimization as the second objective. A robust and flexible parametric model of the IPMSM is developed in ANSYS Maxwell 2D. Various parameters are defined in the rotor and stator geometries to perform an effective multi-objective parametric design optimization. Advanced sensitivity analysis, surrogate modeling, and optimization capabilities of ANSYS optiSlang software are leveraged in the optimization. Furthermore, a demagnetization analysis is performed to evaluate the robustness of the optimized design. At high-speed operation, a rotor core is usually subject to higher deformation due to the high centrifugal force. Thus, rotor stresses are reduced in the optimized design by shaping the flux barriers around the permanent magnets. This enables high structural integrity of the optimized design for high-speed operation along with the improved electromagnetic performance. The multi-physics design approach proposed in this article provides the capability to design and optimize an IPMSM geometry for performance and cost, which are essential objectives to achieve in an electrified powertrain development. Moreover, consideration of rotor stress at high operating speeds extends the applicability of the proposed design approach to high-power, high-speed electric propulsion applications.</div>

Thermal-magnetic performance analysis for smart fluid dampers

Abstract Over the years, the Italian Government has taken significant strides in promoting road safety awareness among the students in high schools to create an awareness of prevention and a consciousness of road safety in the student population. In this context, an agreement was signed between the DICEAM Department of the “Mediterranea” University of Reggio Calabria (Italy) and the “Euclide” Higher Education Institute Bova Marina (Italy) to combine road safety with research science in the Science, Technology, Engineering, and Mathematics (STEM) area. With the primary aim of “knowing in order to act”, the students focused on the multi-physics design of magnetorheological fluid dampers as high-performance devices (simple to design and requiring reduced maintenance) for vehicle suspensions, especially class B vehicles. By combining road safety considerations with multi-physics scientific disciplines, the project seeks to emphasize the importance of prevention and knowledge-based action. The study explores the use of magnetorheological fluid dampers, powered by electric current and magnetic induction distribution with thermal loads, to provide appropriate yield stress for developing damping action with repercussions on the quality of road safety. The paper delves into the basic principles of FEM (Finite Element Method) techniques for analyzing an MR damper from both magnetostatic (the main cause generating the damping effect) and thermal perspectives (thermal effects are strongly influenced by environmental conditions). The analysis of an asymmetrical device, where the damping action relies on an MR fluid strip, reveals the significant influence of magnetic and thermal stresses on the magnetization of individual particles and the overall viscosity of the MR fluid.

Multiphysical Design and Optimization of High-Speed Permanent Magnet Synchronous Motor with Sinusoidal Segmented Permanent Magnet Structure

Multiphysical Design and Optimization of High-Speed Permanent Magnet Synchronous Motor with Sinusoidal Segmented Permanent Magnet Structure

Vibroacoustic topology optimization for sound transmission minimization through sandwich structures

Recently, metamaterials, sandwich panels, and a combination of both have shown potential for creating lightweight, load-bearing structures with good noise and vibration suppression properties. However, designing these structures is difficult due to the complex vibroacoustic innate physics and the need to balance conflicting requirements. Structural optimization methods can help address this multi-functional, multi-physical design challenge. While much research has been conducted on optimizing the materials and sizes of plates and sandwich cores, the systematic topological design of fully coupled vibroacoustic cores has not yet been explored. To address this gap, this work presents a topology optimization framework for the vibroacoustic design of sandwich structure cores, with the goal of minimizing sound transmission while constraining volume and structural stiffness. The framework is used to conduct a systematic design analysis, focusing on the dynamic behavior of the optimized structures. The versatility of the methodology is demonstrated by analyzing different targeted frequency ranges, different angles of incidence and the trade-off between the acoustic and structural performance. The resulting designs are lightweight, load-bearing, and achieve high sound transmission loss performance, exceeding the mass law by 15–40 dB in targeted frequency ranges of 500Hz in the interval between 1000Hz and 3000Hz.

Multiobjective Optimization and Multiphysics Design of a 5 MW High-Speed IPMSM Used in FESS Based on NSGA-II

The flywheel energy storage system (FESS) has high-power density and fast response speed, hence it is widely used as a pulse power supply. For the high-speed permanent magnet synchronous machine (HSPMSM) used in high-power FESS, there are two technical problems that need to be solved, including huge centrifugal forces of the rotor at a high-speed operation region and large phase currents at a low-speed operation region. In this paper, a 5 MW high-speed interior PMSM (HSIPMSM) is designed for FESS. The design goal of this electric machine is to reduce the maximum phase current at the lowest speed as much as possible while ensuring the rotor mechanical strength. Based on the response surface (RS) model and non-dominated sorting genetic algorithm II (NSGA-II), the multiobjective design of the HSIPMSM is accomplished using 29 groups of multiphysical field finite element analysis (FEA) sampling experiments. The computational cost is effectively reduced. In addition, the constant power optimal trajectory and control switching speed of the HSIPMSM are analyzed and discussed, and the reason that the constant power flux weakening region of the designed HSIPMSM is not wide and the maximum torque per ampere (MTPA) mode is adopted at a low-speed operation region is further illustrated.

System-Level Consideration and Multiphysics Design of Propulsion Motor for Fully Electrified Battery Powered Car Ferry Propulsion System

The Korean government is facing growing concern over the increasing levels of fine dust. A significant contribution to this problem comes from coastal vessels. To mitigate this, an electric ship propulsion system has been proposed as a solution to reduce air pollution. The application of a fully electric propulsion system in a ship is challenging due to size, capacity limitations, and the cost investment of the battery system. To address the challenges of battery limitation and initial investment costs, the development and supply of removable battery supply systems (RBSSs) for fully electrified battery powered (F-EBP) car ferries are studied. A permanent magnet synchronous motor (PMSM) for the F-EBP car ferry using a roll-on/roll-off-type RBSS is developed in this work. Firstly, the concept of the F-EBP car ferry is discussed, and the specifications of the electric car ferry propulsion system are provided. Secondly, motor design and electromagnetic analysis are performed using finite-element analysis (FEA), where the heat sources including copper loss, core loss, and PM loss are calculated. Mechanical loss is also considered. Finally, a thermal network of the motor is built considering the lumped-parameter model. The results of the thermal analysis indicate that the motor operates within the safe region and can perform well in rated working conditions.

A Computationally Efficient High-Fidelity Multi-Physics Design Optimization of Traction Motors for Drive Cycle Loss Minimization

Continuous improvement in performance of interior permanent magnet (IPM) machines is critical for electric vehicle traction applications. However, due to the cross-coupling and saturation effects, a significant amount of time-consuming finite element analysis (FEA) simulations are required to accurately estimate machine performance. Moreover, iterative design optimization will take significantly longer. In this article, an improved rapid performance estimation technique utilizing surrogate models is developed and coupled with a design optimization algorithm. The proposed framework has significantly less computational cost than alternative surrogate-based approaches, and efficiently employs drive cycle loss minimization for a multi-physics, multi-objective traction motor design optimization. Simulation and experimental results suggest the proposed optimization framework yields optimal designs more efficiently than existing methods while maintaining accuracy.

Multiphysics Design of a Resonator Tuning System and Dimensionless Formulae

Multiphysics Design of a Resonator Tuning System and Dimensionless Formulae

Material selection of intraoral stents for head and neck cancer patients undergoing radiation therapy: A Multi-criteria, Multi-physics design approach

Radiation therapy (RT) plays a key role in curative-intent treatments for head and neck cancer (HNC). Despite the advancements in RT, high doses of radiation can disrupt the oral cavity homeostasis and result in undesired reactions. Thus, intraoral stents (IOSs) are utilized for patients during RT to prevent unnecessary irradiation to surrounding tissues. However, no studies have compared commonly used IOS materials and their potential toxicity. Therefore, the objective of this study is to perform a detailed assessment of ten IOS materials in order to select the top-ranked material for HNC patients undergoing RT. Thus, beam attenuation measurements, and Raman spectroscopy and mechanical testing were conducted pre- and post-artificial saliva, RT, and artificial saliva and RT exposure. Finally, through a multi-criteria decision making (MCDM) analysis using Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), our study demonstrated that Ethylene Vinyl Acetate (EVA) was the top-ranked material. The saliva samples were also tested via nuclear magnetic resonance (NMR) spectroscopy, which showed no leaching of irradiated materials. Taken together, these data suggest that EVA is an appropriate IOS material that can be utilized during RT to reduce significant morbidity for HNC patients and improve their quality of life.

Design Considerations of Magnet Configurations in Interior Permanent Magnet Machines for High-Speed Traction Applications: A Comprehensive Study

This article presents a comprehensive comparison and the design considerations of three magnet configurations in interior permanent magnet (IPM) machines for high-speed traction applications. The study investigates single-V, double-V, and single-U magnet configurations. A multiphysic multiobjective optimization is used to enhance the three machines, which are designed with a constraint to fit in the same housing and have the same torque-speed curve. The optimized configurations are then compared with respect to multiple performance indices according to common design criteria for traction motors, including no-load characteristics, short circuit characteristics, demagnetization, torque, efficiency, loss distributions, continuous performance, and magnet volume. The study presents how multiphysics design requirements affect the selection of magnet configurations: a single-V rotor configuration can be selected to have the lowest magnet usage as well as high torque density; while the double-V design is suitable for noise-sensitive, high-efficiency applications but requires a rotor-cooling system; and the single-U design is a good candidate for managing tradeoffs among the other options while maintaining a high degree of freedom in the design.

Multiphysics Design Optimization via Generative Adversarial Networks

Abstract This work presents a method for generating concept designs for coupled multiphysics problems by employing generative adversarial networks (GANs). Since the optimal designs of multiphysics problems often contain a combination of features that can be found in the single-physics solutions, we investigate the feasibility of learning the optimal design from the single-physics solutions, to produce concept designs for problems that are governed by a combination of these single physics. We employ GANs to produce optimal topologies similar to the results of level set topology optimization (LSTO) by finding a mapping between the sensitivity fields of specific boundary conditions, and the optimal topologies. To find this mapping, we perform image-to-image translation GAN training with a combination of structural, heat conduction, and a relatively smaller number of coupled structural and heat conduction data. We observe that the predicted topologies using GAN for coupled multiphysics problems are very similar to those generated by level set topology optimization, which can then be used as the concept designs for further detailed design. We show that using a combination of multiple single-physics data in the training improves the prediction of GAN for multiphysics problems. We provide several examples to demonstrate this.

Multiphysics design and fabrication of 3D electroplated VIA materials topographies for next generation energy and sensor technologies

3D micro and nanoconductors have emerged as essential components of next generation energy and sensor technologies. This work investigates novel methods to tailor the topography of electroplated 3D conductive components, such as VIAs, using the FEM in COMSOL Multiphysics. This enables meeting the design specifications of flat, convex, or concave substrate-distal electroactive surfaces. Flat conductor surfaces are ideal for microbump soldering and flip-chip fabrication methods and concave/convex designs increase the number of available electrode reaction sites for sensor applications. 2D/3D multiphysics simulations are performed comprising: (1) electrochemistry modeling with the Nernst-Planck and Butler-Volmer formulations for mass transfer and reaction kinetics, and (2) a deformed geometry physics module to track the growing electrode during electrodeposition. Simulation results are compared to directly corresponding experimental work, with positive correlation. Our findings enable tailored and scalable electroactive surface processing options, which can be readily integrated into pre-existing research and industry standard operating procedures.

Multiphysics Design of an Automotive Regenerative Eddy Current Damper

This research presents a finite element multi-physics design methodology that can be used to develop and optimise the inherent functions and geometry of an innovative regenerative eddy current (REC) damper for the suspension of B class vehicles. This methodology was inspired by a previous work which has been applied successfully for the development of an eddy current (EC) damper used for the same type of applications. It is based on a multifield finite element coupled model that can be used to fulfil the electromagnetic, thermal, and fluid dynamic field properties and boundary conditions of a REC damper, as well as its non-linear material properties and boundary conditions, while also analysing its damping performance. The proposed REC damper features a variable fail-safe damping force, while electric power is advantageously regenerated at high suspension frequencies. Its damping performance has been benchmarked against that of a regular hydraulic shock absorber (selected as a reference) by analysing the dynamic behaviour of both systems using a quarter car suspension model. The results are expressed in terms of damping force, harvested power, thermal field, comfort and handling, with reference to ISO-class roads. The optimisation analysis of the REC damper has suggested useful guidelines for the harmonisation of damping and regenerative power performances during service operation at different piston speeds.

(Opening Keynote) Heterogeneous Functional Materials: Their Present Science and Engineering, and Their Role in the Future of Our Society

Devices that convert and store energy are generally made from heterogeneous constituent materials that act and interact to selectively conduct, transport, and regulate mass, heat, and charge. Controlling these functional actions and interactions enables the technical breakthroughs that have made high efficiency fuel cells, batteries, and solid state membranes, for example, essential parts of our society and economy. In the biological sense, these materials are ‘vascular’ rather than primitive ‘cellular’ materials, so that the arrangements and configurations of the constituents play essential roles in their functional capabilities. Local interactions of the constituents create “emergent” properties and responses that are not part of the formal set of constituent characteristics, in much the same sense that society and culture is created by the group interactions of the people involved. The design of emergent properties is an open question in all formal science, but for energy materials the lack of this foundation science relegates development tasks to Edisonian trial and error, with anecdotal success and frequent costly failures. The present group has defined, for the first time, multi-scale heterogeneous functional materials with functional disordered and void phase regions as “HeteroFoaM,” and formed the first multidisciplinary research team (EFRC) to define and codify the foundation science of that material class. The primary goal of the HeteroFoaM Center was, and the continuing interest is, to create and establish the multi-scale fundamental knowledge and related methodology required for the rational and systematic multiphysics design of heterogeneous functional materials and their interfaces and surfaces for applications in energy transformation and storage. HeteroFoaM is a new atoms-to-systems paradigm that is intended to bring heterogeneous functional materials (for which the system is rarely simply the sum of the parts) into the modern age of computational materials to achieve the savings of time and cost associated with trial and error Edisonian design.The promise of this pursuit is to construct a Multi-Scale/Multi-Physics (M2SP) Design Science for Heterogeneous Functional Materials that is codified in models and codes that enable the design of material systems to convert fuels directly into electricity, store energy in easily transported forms, and separate strategic materials including nuclear waste.The HeteroFoaM paradigm is an approach that focuses on the “conformal science” that defines the local interactions that result from the arrangements and configurations of the constituents. The approach fully embraces the complexity of heterogeneous functional material systems including the uncertainty of predictions and observations, the creation of a formal structure for combining analysis, simulations, and experiments, and the creation of a science path to the prediction of emergent global response probabilities based on the local or meso-science of constituent interactions. However, since this concept was originated almost 10 years ago, a technical revolution has happened in our world society that makes progress in this field even more imperative. There has been an historic shift in our society to hydrogen as a preferred fuel, with industrial and governmental promises that it will be nearly an exclusive choice for society and industry in the next ten years or so. Therefore, our discussion will begin with the historic foundations of this field and end with a short summary of the remarkable and historic changes in society that have elevated this subject to a central and critical science and engineering subject for our world society today.

The simulation of a new high frequency transformer

Core losses of transformers motivate many engineers and scientists to design and implement different transformers for their specific aims. Since there exists a growing interest on high frequency applications in today’s world, design and optimization studies of a magnetic fluid core transformer (MFCT), having an easy and cheap production approach in high frequency applications, are considered in the present paper. The desired design should operate in a more efficient way within a wide frequency band. The MFCT considered here can be a solution to the eddy currents and core losses encountered in the conventional transformers with its low conductivity, oil-based magnetic fluid and super paramagnetic characteristic. The magnetic fluid in the proposed work consists of a combination of ferromagnetic particles made by iron in an averaged diameter of 70 µm with an adjustable magnetism compared to the traditional magnetic fluids and an engine oil, thereby the magnetic permeability of the overall fluid core can be fully adjustable by the variation of mass proportion between the oil and iron powder as an easy process without any chemical process. A COMSOL Multi-Physics design is performed via a finite element package in three dimensions. It is proven that the iron particles exhibit a complicated pattern inside the engine oil and produce a well-defined high frequency output at the secondary windings in a wide range of frequency.

Semi‐empirical development of a novel and versatile multiobjective optimization tool for co/trigeneration energy system design

This article describes a novel and implemented optimization routine for the analysis of combined cooling, heat, and power generation. The optimization model is briefly described both in terms of logic and operation and in terms of mathematical formalization. The model is able to optimize energy systems with different technologies used for the cogeneration unit, namely, SOFC and PEM fuel cells, internal combustion engines (ICEs), and micro-gas turbines (MGTs). The validation is performed both in terms of energy efficiency curves and in terms of unit costs, for all components within the energy system, including energy storage systems, heat pumps, and auxiliary boilers. The main key performance indicators included in the technical analysis of the CCHP units are the nominal electric and overall efficiency as a function of installed size and during a partial load operation, as well as the power-to-heat factor in dependence upon the nominal capacity/power. Two main storage technologies have been included, namely lithium-ion batteries (Li-ion BES) and lead-acid batteries (LA BES). The heat pump portfolio allows the choice between compression gas heat pumps (CGHPs) and absorption heat pumps (ABHPs), with their COP and EER described as a function of the external temperature and of a partial load operation. The validation of the modeled curves is performed in comparison with data of existing commercial units, presenting a correlation factor over 95% for most of the technologies. Highlights Presentation of a multiphysical design tool for CCHP systems; Economic, technical, and environmental analysis and optimization; PEMFC and SOFC are included in the tool technology portfolio; The model is based on validated and semi-empirical correlations; Evaluation of different energy storage systems and heat pump technologies. The present article describes the validation of an innovative multiobjective model aiming to optimize both the operating strategy of the plant and the sizing of the main equipment in a correlated way. The article focuses on the validation of the proposed model and, as a further novelty, includes a broad technological portfolio in terms of cogeneration units and describes the semi-empirical validation of the model by comparing the cost and performance curves modeled with existing market elements or literature data.