Advanced Design Stage Research Articles

Electromechanical Modeling and Analysis of Motor Whine in Electric Propulsion Systems

Electric motor whine is a major source of tonal noise and vibration for electric propulsion systems. The lack of engine masking noise in electric vehicles (EVs) further pronounces the pure tones, which are annoying to the occupants. The associated vibration can cause durability issues due to resonance and lead to failure of the sub-assembly or the supporting structure. A source-level NVH assessment of electric propulsion systems in modern EVs aims to achieve first-time quality designs at the advanced design stage. Accurate modeling of the motor stator and the electromagnetic (EM) forces at the air gap between the stator and rotor are critical to the NVH assessment. This work investigates the interaction between EM force application and the stator design in all four quadrants in which the electric motor operates, including both driving and regenerative braking in both clockwise and counterclockwise directions. A finite element (FE) model of the stator is developed, and the EM forces are mapped on the stator teeth, including different clocking and application directions. The stator model is integrated in the electric drive unit (DU) model, which enables the evaluation of the NVH performance of the propulsion system due to the reversal the EM force directions. The predicted analysis results are compared with the measured mount vibration

OECD/NEA/CSNI state-of-the-art report on scaling in system thermal-hydraulics applications to nuclear reactor safety and design (The S-SOAR)

The present paper deals with scaling in nuclear-system thermal-hydraulics (SYS TH), including the connection with Nuclear Reactor Safety Technology (NST). The paper is entirely derived from the S-SOAR document issued by CSNI of NEA, NEA/CSNI/R(2016)14, 2016 (Bestion et al., 2016). Scaling has constituted ‘an issue’ since the beginning of the exploitation of nuclear energy for civil purposes, with main reference to the generation of electricity. A Nuclear Power Plant (NPP) constitutes a technologically complex industrial system and it is characterized by the impossibility of, or the large difficulty in, characterizing the system’s performance under the conditions of the design. So, models were designed, constructed, and operated under downscaled ranges of values for one or more of selected parameters (e.g. power, volume, height, pressure, etc). These features lay at the origin of the scaling issue, i.e. the difficulty in demonstrating that a model behaves like the prototype. Integrated definitions of the widely adopted terms, ‘scaling’, ‘scaling issue’, and ‘addressing the scaling issue’ are part of the present document. The related application domain includes the NST, and the licensing for water-cooled nuclear reactors under operation, under construction, or under an advanced design stage at the time of publication of the (Bestion et al., 2016). Scaling-related analyses are done in different areas of SYS TH and NST. These include the design of test facilities (both integral and separate-effect test facilities, IETF and SETF), the design of experiments (including Counterpart Test, CT), the demonstration of the capability of any computational tool, and the evaluation of uncertainty affecting the prediction of the same computational tools. A variety of approaches have been used to address the scaling issue, including non-dimensional analysis of mass, energy- and momentum-balance equations, derivation and application of scaling factors, including the hierarchy of relative importance, performing experiments at different scales, and running the SYS TH computer codes. This paper discusses the key areas and the key approach for scaling. It was found that the SYS TH computer codes, following their application to differently scaled experiments, demonstrate that the accuracy of their predictions may not depend upon the scale of the considered experiments. The TH codes also may constitute an additional valuable tool for addressing the issue of scaling.

Shaping bridge decks for VIV mitigation: A wind tunnel data-driven adaptive surrogate-based optimization method

Vortex-induced vibration (VIV) of deck girders frequently drives the wind-resistant design of wind-sensitive bridges from the preliminary to final design stages. Shaping bridge decks is a proven strategy to mitigate VIV. While significant shape modifications are commonly restricted to preliminary design stages, only minor medications are possible at advanced design stages, typically involving adding flow modifiers or changing the shape and location of existing appendages. These mitigation strategies have been implemented in the last decades by carrying out expensive wind tunnel campaigns and following heuristic design rules. This paper proposes an experimental data-driven adaptive surrogate-based optimization approach to systematically identify optimum deck shapes that minimizes the economic cost of the bridge while fulfilling the VIV project specifications. The methodology is conceived to carry out simultaneously the general and detailed shape design of the final deck configuration by harnessing a sequential sampling plan aiming at reducing the sectional model construction costs. The proposed holistic design framework is successfully applied to a real application case involving 26 wind tunnel tests of 1.8-meter wide sectional models to figure out the optimal gap distance and location of maintenance tracks of a twin-box deck equipped with all the appendages included in the final deck design.

Estimating the Cost of Wave Energy Converters at an Early Design Stage: A Bottom-Up Approach

The role of ocean energy is expected to grow rapidly in the coming years, and techno-economic analysis will play a crucial role. Nowadays, despite strong assumptions, the vast majority of studies model costs using a top-down approach (the TdA) that leads to an unrepresentative economic model. WEC developers usually go through the the TdA approach because more detailed cost data are not available at an earlier design stage. At a very advanced design stage, some studies have also proposed techno-economic optimisation based on the bottom-up approach (BuA). This entails that the detailed cost metrics presented in the literature are very specific to the WEC type (hence not applicable to other cases) or unrepresentative. This lack of easily accessible detailed cost functions in the current state of the art leads to ineffective optimisations at an earlier stage of WEC development. In this paper, a BuA for WECs is proposed that can be used for techno-economic optimisation at the early design stage. To achieve this goal, cost functions of most common components in the WEC field are retrieved from the literature, exposed, and critically compared. The large number of components considered allows the results of this work to be applied to a vast pool of WECs. The novelty of the presented cost functions is their parameterization with respect to the technological specifications, which already enables their adoption in the design optimisation phase. With the goal of quantifying the results and critically discuss the differences between the TdA and the BuA, the developed methodology and cost functions are applied to a case study and specifically adopted for the calculation of the capital cost of PeWEC (pendulum wave energy converter). In addition, a hybrid approach (HyA) is presented and discussed as an intermediate approach between the TdA and the BdA. Results are compared in terms of capital expenditure (CapEx) and pie cost distribution: the impact of adopting different cost metrics is discussed, highlighting the role that reliable cost functions can have on early stage technology development. This paper proposes more than 50 cost functions for WEC components. Referring to the case study, it is shown that while the total cost differs only slightly (11%), the pie distribution changes by up to 22%. Mooring system and power take-off are the cost items where the TdA and the HyA differ more from the BuA cost estimate.

Estimation of the power dissipation on the casing of DTT toroidal field coil during a fast plasma disruption

The aim of this paper is the computation of the power dissipated on the Toroidal Field Coil (TFC) casing of the Divertor Tokamak Test facility (DTT). The DTT Tokamak will be installed in Fascati (Italy), and is in an advanced design stage. The magnetic system will be realized with superconducting coils so that the correct dimensioning of the cooling system is mandatory. As a consequence, a detailed knowledge of the main sources of dissipation is required. Our attention will here be focused on the TFC casing and, in particular, on the dissipations due to the eddy currents induced on the casing by time-varying magnetic field during a Fast Plasma Disruption (FPD). A finite element model whose geometry has partly been imported into Ansys 2021/R2 SpaceClaim (TFC casing), and partly made in Ansys 2021/R2 DesignModeler (plasma, Vacuum Vessel (VV) and Stabilizing Plates (SP)), has been implemented in Ansys 2021/R2 Maxwell 3D to perform a transient analysis of the FPD event. The current induced on the TFC casing, as well as the total power losses, are the output of our computation to be used for the cooling system dimensioning. In order to estimate the heat rate to be removed during normal operation, the breakdown and Single Null (SN) scenarios have also been studied.

Mechanical DesignVerification for the moderated neutron source at SARAF

The accelerator-driven thermal neutron source (TNS) at SARAF is under the advanced design stage, to provide an accelerator-based substitution to existing neutron imaging and diffraction utilities of the IRR1 aging research reactor. A challenging task of the system design is to provide a safe and maintainable coupling of 40 MeV deuteron beam and a 200 kW power liquid metal target with a compact light-water moderator and reflector assembly. The verification process of the mechanical design is performed through Monte-Carlo simulations over the detailed CAD models. We outline the method of verification of neutron production and safety requirements over the detailed system design and highlight the advantages of this approach.

Exploring the Effects of Climate-Adaptive Building Shells: An Applicative Time-Saving Algorithm on a Case Study in Bologna, Italy

Adaptive façades represent a viable and effective technological solution to reduce the building energy demand for cooling while achieving interesting aesthetic effects on the building envelope to screen solar radiation. During the last decade, many different design solutions, including those based on shape memory alloys, have been experimented to obtain appropriate responses without being dependent on electro-mechanically actuated systems. Several recent and ongoing studies have been published in the scientific literature regarding the different actuator typologies, as well as the different properties of the materials used, which usually determine the adaptive solution characteristics after a series of complex and time-consuming simulations using specialised dynamic modelling software. Due to the time and resources required, this kind of evaluation is usually delivered during the last and more advanced design stage as a form of assessment of already-taken architectural and technological choices. The study reported in the paper aims to offer a quick, time-saving simplified algorithm to calculate the response of an adaptive façade, according to the ISO 13790 standards, to be adopted during the early design stage to evaluate the possible effects of design decisions. The study includes three main steps: (a) the conceptualisation of the adaptive solution considering the context conditions; (b) the definition of the calculation algorithm; (c) the application of the method to a test room in a case study building located in Bologna for supporting the discussion of the related outcomes.

Progress of Design and Development for the ITER Radial Neutron Camera

The paper presents an overview of the design status of the Radial Neutron Camera (RNC), that, together with the Vertical Neutron Camera, will provide, through reconstruction techniques applied to the measured line-integrated neutron fluxes, the time resolved measurement of the ITER neutron and α-source profile (i.e. neutron emissivity, neutrons emitted per unit time and volume). The RNC is composed of two subsystems, the In-Port RNC and Ex-Port RNC located, respectively, inside and outside the Plug of Equatorial Port #01. The In-Port subsystem is in a more advanced design stage since it has recently undergone the Final Design Review in the ITER procurement process. The paper describes the diagnostic layout, the interfaces, the measurement capabilities and the main challenges in its realization. Prototyping and testing of neutron detectors and electronics components were carried out and led to the choice of the component solutions that can match the environmental and operational constraints in terms radiation hardness, high temperature and electromagnetic compatibility. The performance of the RNC in terms of neutron emissivity measurement capability was assessed through 1D and 2D reconstruction analysis. It is proven that the neutron emissivity can be reconstructed in real-time within the measurement requirements: 10% accuracy, 10 ms time resolution and a/10 (a = plasma minor radius) space resolution.

A decision-making process for the selection of better ship main dimensions by a Pareto frontier solution

Initial ship design necessitates the evaluation of main ship parameters to obtain a feasible design solution satisfying the objectives. Traditionally, relationship between main dimensions and design parameters of proven designs provides a safe solution. This approach restrains the designer from improving the design with respect to conflicting design criteria. Pareto frontier technique has widely been utilized in the design of ships, mainly at advanced design stages for optimization problems. As the principal dimensions of a ship are also vital on the performance of the vessel, major improvements in performance may be achieved by selecting better principal dimensions. This paper proposes to integrate the Pareto technique to the design cycle at an early stage as a decision-making process for selection of better main dimensions with respect to multiple conflicting criteria A Pareto Front has been observed for two case studies (a destroyer and a planing craft) indicating a technological barrier for performance with respect to main dimensions. As the design process begins with main dimensions along the technological barrier, performance is improved with respect to conflicting design criteria at the beginning of the design process which serves as a better basis for further optimization studies to be conducted at advanced stages.

Modified Core Loss Calculation for High-Speed PMSMs With Amorphous Metal Stator Cores

This paper presents the modified core loss calculation of the high-speed (HS) permanent magnet synchronous machines (PMSMs) with amorphous metal (AM) stator cores. In the initial stage of the HS PMSM design, the calculation of stator core loss is obtained according to the data of AM ribbon provided by the manufacturer, which causes a large error of AM core loss. So how to make the accurate calculation of the AM core loss with only the AM ribbon data from the manufacturer is impending in the initial and advanced design stages of HS PMSM development. In this paper, the characteristics of AM ribbon and AM stator core is measured and compared. According to the experimental results, the modification factor for the accurate calculation of AM core loss is obtained based on the loss characteristics of AM ribbon. Then, the no-load loss of a HS PMSM prototype with an AM stator core is analyzed by numerical methods and verified by experiments. The proposed modification factor of the AM core loss calculation can provide a reference for the design and analysis of HS AM PMSMs in the industry.

Conceptual structural system layouts via design response grammars and evolutionary algorithms

Two new methods to generate structural system layouts for conceptual building spatial designs are presented. The first method, the design response grammar, uses design rules—configurable by parameters—to develop a structural system layout step by step as a function of a building spatial design's geometry and preliminary assessments of the structural system under development. The second method, design via optimizer assignment, uses an evolutionary algorithm to assign structural components to a building spatial design's geometry. In this work, the methods are demonstrated for two objectives: minimal strain energy (a commonly used objective for structural topology optimization) and minimal structural volume. In a first case study three building spatial designs have been subjected to the methods: Design via optimizer assignment yields a uniformly distributed Pareto front approximation, which incorporates the best performing layouts among both methods. On the other hand, results of the design response grammar show that layouts that correspond to specific positions on the Pareto front (e.g. layouts that perform well for strain energy), share the same parameter configurations among the three different building spatial designs. By generalizing, specific points on the Pareto front approximation have been expressed in terms of parameter configurations. A second case study addresses the use of a generic material and generic dimensions in the assessment of structural system layouts. The study applies a technique similar to topology optimization to optimize the material density distribution of each individual structural component, which can be regarded as a part of determining materials and dimensions in more advanced stages of the design of a system layout. This optimization approach is applied to the layouts that are part of the Pareto front approximations as found by the evolutionary algorithm in the first case study, the study shows that—after optimization—the fronts remain the same qualitatively, suggesting that the methods produce results that are also useful in more advanced design stages. A final case study tests the generalization that is established in the first case study by using the found configurations for the design response grammar, and it is shown that the generated layouts indeed are positioned near the desired positions on the Pareto front approximation found by the evolutionary algorithm. Although the evolutionary algorithm can find better performing solutions among a better distributed Pareto front approximation, the design response grammar uses only a fraction of the computational cost. As such it is concluded that the design response grammar is a promising support tool for the exploration and structural assessment of conceptual building spatial designs. Future research should focus on more types of structural elements; more objectives; new constraints to ensure feasible solutions, especially stress constraints; and the application of state-of-the-art techniques like machine learning to find more generalizations.

An integrated framework for multi-criteria optimization of thin concrete shells at early design stages

Thin shells are crucially dependent on their shape in order to obtain proper structural performance. In this context, the optimal shape will guarantee performance and safety requirements, while minimizing the use of materials, as well as construction/maintenance costs.Thin shell design is a team-based, multidisciplinary, and iterative process, which requires a high level of interaction between the various parties involved, especially between the Architecture and Engineering teams. As a result of technological development, novel concepts and tools become available to support this process. On the one hand, concepts like Integrated Project Delivery (IPD) show the potential to have a high impact on multidisciplinary environments such as the one in question, supporting the early decision-making process with the availability of as much information as possible. On the other hand, optimization techniques and tools should be highlighted, as they fit the needs and requirements of both the shell shape definition process and the IPD concept. These can be used not only to support advanced design stages, but also to facilitate the initial formulation of shape during the early interactions between architect and structural engineer from an IPD point of view.This paper proposes a methodology aimed at enhancing the interactive and iterative process associated with the early stages of thin shell design, supported by an integrated framework. The latter is based on several tools, namely Rhinoceros 3D, Grasshopper, and Robot Structural Analysis. In order to achieve full integration of the support tools, a custom devised module was developed, so as to allow interoperability between Grasshopper and Robot Structural Analysis. The system resorts to various technologies targeted at improving the shell shape definition process, such as formfinding techniques, parametric and generative models, as well as shape optimization techniques that leverage on multi criteria evolutionary algorithms. The proposed framework is implemented in a set of fictitious scenarios, in which the best thin reinforced concrete shell structures are sought according to given design requirements. Results stemming from this implementation emphasize its interoperability, flexibility, and capability to promote interaction between the elements of the design team, ultimately outputting a set of diverse and creative shell shapes, and thus supporting the pre-design process.

Thermal-hydraulic phenomena for water cooled nuclear reactors

Nuclear Reactor Safety (NRS), Deterministic Safety Assessment (DSA) and Accident Analysis (AA) constitute the general framework for the topic of the present paper. The class of Water-Cooled Nuclear Reactors (WCNRs) is concerned. This includes most of the nuclear reactors in operation, under construction or in advanced design stage. The required licensing process for those reactors, are further necessary elements to establish the context of the performed activity.Best Estimate (BE) system thermal-hydraulic codes are adopted to demonstrate the safety of WCNR based on AA, namely focusing on the class of Design Basis Accidents (DBAs). On the one hand, the validation of BE codes is a necessary step to prove their applicability to calculate accident scenarios. On the other hand the knowledge of accident scenarios is a requirement for the design and the operation of WCNR. The validation of BE codes and the knowledge of accident scenarios needs the identification and the characterization of Thermal-hydraulic Phenomena (T-HP).A list of 116 T-HP is derived in the present paper, based on the documents issued in the last three decades by the Committee on the Safety of Nuclear Installations of Nuclear Energy Agency of The Organization for Economic Cooperation and Development (OECD/NEA/CSNI) and by the International Atomic Energy Agency (IAEA). The T-HP list includes the consideration of Separate Effect Tests (SET) and Integral Effect Tests (IET) relevant in Reactor Coolant System (RCS) and Containment of WCNRs. A dozen WCNR types are considered and include Pressurized Water Reactors (PWRs), Boiling Water Reactors (BWRs), Russian design reactor types (e.g. VVER-440, VVER-1000 and RBMK), pressure tube heavy water reactor designs in Canada (CANDU) and in India (PHWR) and so-called ‘advanced’ reactors (in the text of this paper, they are sometimes assigned as “New Reactors”), which are also equipped with passive systems (for instance, AP-1000 and APR-1400 designed in US and Korea, respectively).Each T-HP can be characterized by one or more parameters or variables which are part of numerical models and constitute calculational results from system codes. A cross link process can be established between T-HP, parameters and DBA scenarios. The basis for the process and selected cross-link examples are provided and discussed.A variety of applications for the T-HP list is envisaged in nuclear thermal-hydraulics. Insights are given in the paper in relation to the use of phenomena: a) to address the scaling issue; b) to distinguish between constitutive equations part of the balance equations and ‘special models’ in BE system codes; c) to prioritize research in nuclear reactor thermal-hydraulics.

Safety assessment of punching shear failure according to the level of approximation approach

AbstractThe fib Model Code for Concrete Structures 2010 introduced the concept of levels of approximation (LoA) as a strategy for simplifying the procedures involved in preliminary design stages or the design of non‐critical structural elements while still providing the tools for engineers to use state‐of‐the‐art techniques in the assessment of existing structures or in the advanced stages of design for critical structural elements. In this paper, this concept is applied to the determination of the punching shear resistance of reinforced concrete slabs. A procedure is validated for the highest LoA involving non‐linear finite element analysis (NLFEA) with multi‐layered shell elements and the critical shear crack theory (CSCT). The safety format proposed for use in the safety verification assisted by NLFEA is based on the definition of a global resistance safety factor. A semi‐probabilistic approach is followed, based on the assumption of a lognormal distribution for the resistance and on an estimate of its coefficient of variation. This approach is validated by means of a comparison with the results from a probabilistic analysis.The LoA approach is initially applied to the study of statically determinate slabs supported on one column to verify the effectiveness of the procedure presented here compared with other validated methods available in the literature. The paper concludes with a case study illustrating the application of the proposed procedure to a bridge deck slab and highlighting the benefits of using a higher LoA.

Design of a diagnostic residual gas analyzer for the ITER divertor

One of the ITER diagnostics having reached an advanced design stage is a diagnostic RGA for the divertor, i.e. residual gas analysis system for the ITER divertor, which is intended to sample the divertor pumping duct region during the plasma pulse and to have a response time compatible with plasma particle and impurity lifetimes in the divertor region. Main emphasis is placed on helium (He) concentration in the ducts, as well as the relative concentration between the hydrogen isotopes (mainly in the form of diatomic molecules of H, D, and T). Measurement of the concentration of radiative gases, such as neon (Ne) and nitrogen (N2), is also intended. Numerical modeling of the gas flow from the sampled region to the cluster of analysis sensors, through a long (∼8m long, ∼110mm diameter) sampling pipe originating from a pressure reducing orifice, confirm that the desired response time (∼1s for He or D2) is achieved with the present design.

Development and Testing of a Design Protocol for Computer Mediated Multidisciplinary Collaboration during the Concept Stages with Application to the Built Environment

Effective collaboration and maximum effort from stakeholders during the feasibility and concept design stages in architecture provide the greatest potential for added value for the overall success of a building project, from the initial design through to construction and operation. What is more, design processes within different disciplines have been extensively mapped and they provide a valuable insight for managing the information between different conceptual stages. Based on that information, a pre-defined conceptual design protocol is established, tested and compared to the current paradigm of conceptual design. The aim of such a protocol is to enhance the conceptual design activities by guiding the multidisciplinary design team through the conceptual stage, highlight the importance of that stage and, eventually, provide the maximum information that will feed into later and more advanced design stages, aided by tangible user interfaces (TUIs) mediated collaboration. The initial results of the research are showcased and further research potentials are pointed out.

Neighbourhood Peacekeeping: The Inter-American Development Bank's Violence Reduction Programs in Colombia and Uruguay

The Inter-American Development Bank (IDB) incorporated, nearly a decade ago, violence prevention in its lending portfolio. Since the first citizen security project loan was approved, the IDB has accumulated valuable experience on the design and implementation of violence prevention operations, placing the Bank at the forefront of this type of lending in the region. To date, the IDB has financed more than US$150 million for six citizen security loans, technical cooperation projects, and international seminars and meetings. In addition, several other citizen security projects are in advanced stages of design. This report overviews the Bank's work in this area, analysing, based on available data from completed projects, what works and the challenges that remain in reducing and preventing crime and violence. For example, Colombia (Bogotá) and Uruguay have completed their operations with success in the areas of community policing, institutional strengthening, community mediation units, domestic and youth violence prevention, and social awareness campaigns. This report also presents recommendations to maximise benefits and increase the effectiveness of the interventions in future project loans. Despite the accomplishments in this area, it is important to emphasise that crime and violence prevention is not a ‘one shot deal’ but a process that ought to be sustained over time and governments in the region must fully commit to combat it.

Possibilities of implementation of absorption heat pump in realization of the Clausius–Rankine cycle in geothermal power station

The topic of utilization of geothermal power for heating purposes in Poland is relatively well known, which is justified by the fact of a number of operating geothermal power plants and some other installations in a well advanced design stage. Geothermal energy utilization projects for production of electricity are also under development. The results of one of such analysis, regarding the correctness of construction and operation of a binary geothermal power plant in combination with the heat pump, supplied by heat water with low enthalpy, has been discussed in the present paper.

Beyond leukodepletion: removing infectious prions by filtration

Beyond leukodepletion: removing infectious prions by filtration

Visualisation in architecture, engineering and construction (AEC)

In the architecture, engineering and construction industries, computer visualization usage can cover the whole lifecycle of a product from presentation of initial concepts to the final stages of production and can also extend to maintenance issues. Three-dimensional walkthroughs can be created from hand drawn sketches at the very early stages of the design process. Three-dimensional models can be used by design teams to communicate design intent to client and users and to compare and evaluate design options. During more advanced stages of design, three-dimensional representations can be used to check the integrity of services coordination, accessibility and maintainability. During construction, visualization can facilitate the interpretation of design details by site operatives. The concept of visualization is not limited to modeling physical objects but can extend to the representation of abstract data sets of the type obtained from simulation programs used in performance assessment or from Computation Fluid Dynamics (CFD) applications. This paper will review the application of visualization in the process of design and construction and then present findings from three research projects that made use of some of these techniques at various stages of the process: for collaborative working during concept design stage, for design development and marketing in the house building sector, and for the modeling of design details during the construction stage.