Parametric Design Approach Research Articles

A Geodesign Method of Human-Energy-Water Interactive Systems for Urban Infrastructure Design: 10KM2 Near-Zero District Project in Shanghai

Abstract The grand challenges of climate change demand a new paradigm of urban design that takes the performance of urban systems into account, such as energy and water efficiency. Traditional urban design methods focus on the form-making process and lack performance dimensions. Geodesign is an emerging approach that emphasizes the links between systems thinking, digital technology, and geographic context. This paper presents the research results of the first phase of a larger research collaboration and proposes an extended geodesign method for a district-scale urban design to integrate systems of renewable energy production, energy consumption, and storm water management, as well as a measurement of human experiences in cities. The method incorporates geographic information system (GIS), parametric modeling techniques, and multidisciplinary design optimization (MDO) tools that enable collaborative design decision-making. The method is tested and refined in a test case with the objective of designing a near-zero-energy urban district. Our final method has three characteristics. ① Integrated geodesign and parametric design: It uses a parametric design approach to generate focal-scale district prototypes by means of a custom procedural algorithm, and applies geodesign to evaluate the performances of design proposals. ② A focus on design flow: It elaborates how to define problems, what information is selected, and what criteria are used in making design decisions. ③ Multi-objective optimization: The test case produces indicators from performance modeling and derives principles through a multi-objective computational experiment to inform how the design can be improved. This paper concludes with issues and next steps in modeling urban design and infrastructure systems based on MDO tools.

Parametric design to minimize the embodied GHG emissions in a ZEB

This work aims to apply parametric design to minimize the embodied greenhouse gas emissions and operational energy in a zero emission building in Oslo, Norway. An original generative workflow based on parametric design was developed in the Grasshopper environment to conduct energy analyses, such as solar radiation and daylighting, and environmental impact analysis, to evaluate the embodied and operational greenhouse gas emissions of the building. The workflow was generated to control parametrically several building features while varying the building shape, the dimensions of construction components, and the quantity of materials. The process leads to the generation of shapes with the least environmental impact. The workflow allows the modification of the initial shape of the Base Case by running iterative simulations through the Galapagos and Octopus evolutionary solvers. For each stage of the shape's optimization, through passive and active strategies, the embodied emissions and energy balances were estimated to evaluate how the building design varies in terms of energy and environmental impact, and to identify the implications for the design. This paper shows how design options with low levels of embodied emissions can be generated and optimized automatically, and also demonstrates how a parametric design approach provides the designer with suggestions of low-impact solutions, which can then be integrated and considered early in, and throughout, the design process in a holistic manner.

Eksperimentalno istraživanje uticaja parametara procesa termičkog bušenja na kompozite sa metalnom matricom

Friction Drilling is a special drilling technique that utilises the Frictional heat generated between the rotating conical drill bit and the stationary workpiece to soften and penetrate the work. The material which interests our study is the metal matrix composite Copper Silicon carbide (CuSiC) due to its high thermal conductivity which would accelerate the drilling process. Friction drill bits of various cone angles are made out of Tungsten High speed steel. Friction drill bits of various cone angles are made out of Tungsten High speed steel. The purpose of our study is to analyse the influence of the drilling parameters: Friction angle, Feed rate, Workpiece thickness and Spindle speed on Thrust force and Torque both graphically and by means of employing Taguchi's parametric design approach. Experimentation is to be conducted using Taguchi's orthogonal array and the results have to be assessed by analysis of variance (ANOVA).

Decoupled TAB converter with energy storage system for HVDC power system of more electric aircraft

It is an important trend to develop the more electric aircraft (MEA) ±270 V high-voltage direct current (HVDC) power system because of its better reliability, power quality and power density. However, there also exists the low-voltage 28 V DC system in HVDC power system, for the aviation battery and some equipment still rely on it. In traditional MEA power systems, battery is only used as a backup power supply, hardly participating in the adjustment of the power system. On the other hand, the function of turbine engine is unidirectional. Hence, it's necessary to add an energy storage port. In this research, the authors put forward the problems of power coupling and strong non-linearity in traditional three-port triple active bridge (TAB) converters, and propose a decoupled TAB topology, which has the feature of decoupled power flow. The topology is compatible with ±270 V DC, 28 V DC and energy storage system with high-power density and efficiency. In addition, the authors unify the efficiency optimisation problem of dual active bridge topology mathematically and provide an optimal parameter design approach for inductance and turns ratio. Simulation results show the power flow control strategy is appropriate for the topology.

Process Parameter optimization for Producing AA7075/WC composites by Friction stir welding

AA 7075 is an aluminum combination, with zinc as the important alloying constituent. It has a high strength, with similarity to many steels, which has good fatigue strength and normal machinability, but it has less resistance to corrosion compare to many other Al alloys. AA7075 are often used in transport applications such as marine, aviation and automotive due to their high strength-to-density ratio. and also Strength and light weight also desirable in the fields of Rock climbing equipment, bicycle components. Now a day’s joining of metal matrix composites by using Friction stir welding process. This welding produce sound welds in metal matrix composite without any problem while reaction between matrix and reinforcement. In this paper deals with experimental investigation of studies on the effect of process parameters such as tool rotational speed, welding speed, tool pin profile, tilt angle and shoulder diameter on tensile strength of friction stir welded AA7075-6%wt,WC composite joints. Process parameters were determined by Taguchi parametric design approach. The results found That tool rotational speed, welding speed and tool pin profile influence on tensile strength of welded joint.

Sequence-Impedance-Based Harmonic Stability Analysis and Controller Parameter Design of Three-Phase Inverter-Based Multibus AC Power Systems

Three-phase inverter-based multibus ac power systems could suffer from the harmonic instability issue. The existing impedance-based stability analysis method using the Nyquist stability criterion once requires the calculation of right-half-plane (RHP) poles of impedance ratios, which would result in a heavy computation burden for complicated systems. In order to analyze the harmonic stability of multibus ac systems consisting of both voltage-controlled and current-controlled inverters without the need for RHP pole calculation, this paper proposes two sequence-impedance-based harmonic stability analysis methods. Based on the summary of all major connection types including mesh, the proposed Method 1 can analyze the harmonic stability of multibus ac systems by adding the components one by one from nodes in the lowest level to areas in the highest system level, and accordingly, applying the stability criteria multiple times in succession. The proposed Method 2 is a generalized extension of the impedance-sum-type criterion to be used for the harmonic stability analysis of any multibus ac systems based on Cauchy's theorem. The inverter controller parameters can be designed in the forms of stability regions in the parameter space, by repetitively applying the proposed harmonic stability analysis methods. Experimental results of inverter-based multibus ac systems validate the effectiveness of the proposed harmonic stability analysis methods and parameter design approach.

Development of an In-Pipe Robot With Differential Screw Angles for Curved Pipes and Vertical Straight Pipes

The in-pipe robots based on screw drive mechanism are very promising in the aspects of pipe inspecting and maintaining. The novel design of an in-pipe robot with differential screw angles is presented for the curved pipes and vertical straight pipes. The robot is mainly composed of the screw drive mechanism, adaptive linkage mechanism, and the elastic arm mechanism. The alternative adjusting abilities of the mobile velocity and traction, and the adaptive steering ability in curved pipes, are achieved by the special designs. A parameter design approach in consideration of the climbing and steering abilities is proposed in detail for the springs and length of the elastic arms. The results are applied to the prototype design of the robot. In several groups of experiments, the proposed robot is competent to pass through curved pipes and vertical straight pipes. The results prove that the proposed mechanism and parameter design approach are both valid.

Modeling of gas diffusion layers with curved fibers using a genetic algorithm

This paper presents a methodology for modeling microstructures of fibrous porous media with curved fibers. The developed methodology utilizes implicit periodic surface model coupled with the genetic algorithm (GA) optimization to construct the porous microstructures. The fibers profile is represented by the periodic implicit surfaces and their orientation and curvature are determined by GA optimization. To reconstruct the microstructures with higher resemblance to the actual porous media GA is utilized to minimize the fibers stored strain energy and their intersection volumes. Coupling the image processing techniques to the geometry construction procedure the morphological and transport properties of the constructed microstructures are also determined. To verify the feasibility and the accuracy of the proposed methodology the microstructure of Freudenberg H2315 GDL is constructed and characterized. The presented methodology enables a parametric design approach. Thus, the effects of the microstructure's properties e.g., fibers diameter, fibers orientation and porosity of the porous structure on the transport properties of the fibrous media are investigated.

Using integrated parametric control to achieve better daylighting uniformity in an office room: A multi-Step comparison study

In addition to windows, louvers are the most common architectural elements widely used in office buildings to protect them from excessive daylight and improve daylight penetration as well. Advanced glazing, window blinds, other fenestration systems and their automation can further improve daylighting performance. However, the stability and uniformity of daylight distribution throughout a day inside a building remain a challenge. To explore a solution for this issue, this paper proposes an advanced integrated lighting system combining different architectural elements, which can be controlled parametrically. The suitable design of such integrated system is identified through a multi-step comparison study employing parametric design approach. The criteria is to keep a relatively uniform daylight distribution in the range of 300–500lx over 90% of the whole desktop area in a 7-m-deep office room. An office building in New Cairo was chosen for a case study, where it is south oriented with a prevailing condition of clear sky. Hourly results on the 21st of several chosen months are given to show the suitability of the proposed design throughout a year, aiming to explore the maximum use of daylight and hence reduce the energy consumption of electrical lighting. The comparison indicates that the combined use of the integrated system can achieve a satisfactory relatively uniform distribution of daylight over about 90% of the desktop area, within illuminance range of 300–500lx for most of the working hours throughout a year.

D–Q Impedance Based Stability Analysis and Parameter Design of Three-Phase Inverter-Based AC Power Systems

Small-signal stability is an important concern in three-phase inverter-based ac power systems. The impedance-based approach based on the generalized Nyquist stability criterion (GNC) can analyze the stability related with the medium and high-frequency modes of the systems. However,. the GNC involves the right-half-plane (RHP) pole calculation of return-ratio transfer function matrices, which cannot be avoided for stability analysis of complicated ac power systems. Therefore, it necessitates the detailed internal control information of the inverters, which is not normally available for commercial inverters. To address this issue, this paper introduces the component connection method (CCM) in the frequency domain for stability analysis in the synchronous d–q frame, by proposing a method of deriving the impedance matrix of the connection networks of inverter-based ac power systems. Demonstration on a two-area system and a microgrid shows that: The CCM-enabled approach can avoid the RHP pole calculation of return-ratio matrices and enables the stability analysis by using only the impedances of system components, which could be measured without the need for the internal information. A stability analysis method based on d–q impedances, the CCM, and the determinant-based GNC is also proposed to further simplify the analysis process. Inverter controller parameters can be designed as stability regions in parameter spaces, by repetitively applying the proposed stability analysis method. Simulation and experimental results verify the validity of the proposed stability analysis method and the parameter design approach.

Energy Expenditure of Trotting Gait Under Different Gait Parameters

Robots driven by batteries are clean, quiet, and can work indoors or in space. However, the battery endurance is a great problem. A new gait parameter design energy saving strategy to extend the working hours of the quadruped robot is proposed. A dynamic model of the robot is established to estimate and analyze the energy expenditures during trotting. Given a trotting speed, optimal stride frequency and stride length can minimize the energy expenditure. However, the relationship between the speed and the optimal gait parameters is nonlinear, which is difficult for practical application. Therefore, a simplified gait parameter design method for energy saving is proposed. A critical trotting speed of the quadruped robot is found and can be used to decide the gait parameters. When the robot is travelling lower than this speed, it is better to keep a constant stride length and change the cycle period. When the robot is travelling higher than this speed, it is better to keep a constant cycle period and change the stride length. Simulations and experiments on the quadruped robot show that by using the proposed gait parameter design approach, the energy expenditure can be reduced by about 54% compared with the 100 mm stride length under 500 mm/s speed. In general, an energy expenditure model based on the gait parameter of the quadruped robot is built and the trotting gait parameters design approach for energy saving is proposed.

Parametric real-time energy analysis in early design stages: a method for residential buildings in Germany

The greatest potential for optimizing the energy efficiency of buildings is in the early design stages. However, in most planning processes energy analysis is conducted shortly before construction when major changes to the design have a high cost impact. The integration of energy performance analysis in the early design stages is therefore highly desirable, but requires suitable tools able to quickly generate results that can help the planner optimize the building design. Parametric design approaches permit the effortless generation of many variants and therefore represent a suitable way of testing different alternatives in the early design stages. Most plug-ins for parametric design software currently rely on dynamic building performance simulation which provides detailed results, but requires computation times ranging from 20 s to 5 min. As optimization processes typically require several thousand simulations, the computation time can quickly amount to days. The approach presented in this paper proposes a real-time energy demand calculation based on a quasi-steady state method defined by the German standard DIN V 18599 which defines the national implementation of the European Directive on the Energy Performance of Buildings. The results are verified of tests on three residential reference buildings in Germany in comparison with an accredited commercial software product. An application example indicates the great potential for easy-to-use energy optimization in the early design stages.

Parametric study and design approach of off-center bracing systems

Parametric study and design approach of off-center bracing systems

Plasma Arc Cutting Dimensional Accuracy Optimization employing the Parameter Design approach

Plasma Arc Cutting (PAC) is a thermal manufacturing process used for metal plates cutting. This work experimentally investigates the influence of process parameters onto the dimensional accuracy performance of the plasma arc cutting process. The cutting parameters studied were cutting speed (mm/min), torch standoff distance (mm), and arc voltage (volts). Linear dimensions of a rectangular workpiece were measured after PAC cutting following the full factorial design experimental approach. For each one of the three process parameters, three parameter levels were used. Analysis of means (ANOM) and analysis of variances (ANOVA) were performed in order for the effect of each parameter on the leaner dimensional accuracy to be assessed.

Multi response optimization in wire electrical discharge machining of Inconel X-750 using Taguchi’s technique and grey relational analysis

AbstractThe effective optimization of machining process parameters affects dramatically the cost and production time of machined components as well as the quality of the final products. This study presents an investigation on cutting speed and surface roughness of Inconel X-750 using Wire-cut electric discharge machining process. Six input process parameters of Wire-cut Electro Discharge Machining—spark gap voltage, pulse-on time, pulse-off time, wire feed rate, peak current and wire tension—were chosen to study their effects on the selected responses. Taguchi’s design of experiments methodology has been used for planning, designing and conducting the experiments. The grey relational analysis has been applied in conjunction with the Taguchi’s parameter design approach for the optimization of multiple responses. The analysis of variance has been applied to identify the significance of different parameters. Finally the confirmation experiments were performed to validate the predicted optimized results.

An LCC-Compensated Resonant Converter Optimized for Robust Reaction to Large Coupling Variation in Dynamic Wireless Power Transfer

In this paper, a reformed compensation network based on traditional LCL topology is proposed to realize robust reaction to large coupling variation that is common in dynamic wireless charging application. From the perspective of smoothing, the power characteristic against coupling factor and to achieve high efficiency simultaneously, extra reactive element is inserted into the resonant tank to provide higher degree of design freedom, forming the improved LCC type compensated inductive power transfer (IPT) system that features with distinct parameter design approach. Comparing to existing compensation topologies, the optimized LCC compensation topology shows more robust power characteristic against variation of coupling factor and, thus, minimizes the need for complex control which is usually undesired in dynamic charging scheme, thereby helping maintain effective power transfer in dynamic charging application and largely enhancing the systematic controllability. Finally, the effectiveness of the proposed method is experimentally verified. The power transfer profile is smooth against coupling factor to realize high tolerance to position as the power drop is no more than 20% within almost 200% of coupling factor variation.

Two-Dimensional Experimental Investigation of Base-Extension Separation Mechanism with Telescopic Gear

Spacecraft landing missions require a soft landing mechanism to prevent a large shock load and tipping over when landing on various types of terrain. The authors previously invented a novel landing mechanism called a telescopic-gear base-extension separation mechanism that operates by means of energy transfer and an adjustable structure. This mechanism passively adjusts the shape of the landing gear according to the landing terrain and transfers the energy of the lander to a spring as potential energy. The outstanding performance of this landing mechanism was demonstrated analytically in a previous study. However, its feasibility was not confirmed, and an effective parameter design method for various shapes of terrains was not presented. Therefore, in this study, two-dimensional experimental investigations are conducted using a small-scale prototype to assess the feasibility of the landing mechanism for several types of terrain. An effective parameter design approach based on a mathematical model derived from the experimental results is presented in this paper. To improve the robustness of the landing mechanism, the lengths of the telescopic gears should be as large as possible, and the spring stiffness should be tuned within a certain range. For sloped ground in particular, the width of the lander is an additional important design parameter; a smaller width is preferable in theory. A robustness study and several important notes on the practical design aspects of the landing mechanism are summarized in this paper.

Experimental Analysis of the Cutting Forces and Material Removal Rate during Dry Turning of En-36 Steel

In the present case study, an attempt has been made to investigate the effect of process parameters (cutting speed, feed rate and depth of cut) on axial force, radial force, main cutting force and material removal rate in dry turning of En-36 (655M13), using carbide cutting tool. The effects of the selected process parameters on performance characteristics/responses and subsequent optimal settings of the parameters have been accomplished using Taguchi‘s parameter design approach. The result shows that the optimal settings for minimum values of cutting forces are lower values of feed rate, depth of cut and cutting speed are required. For the higher values of material removal rate larger values of feed, depth of cut and cutting speed are desired. The results are further verified by conducting confirmation experiments.

Development of a master model concept for DEMO vacuum vessel

This paper describes the development of a master model concept of the DEMO vacuum vessel (VV) conducted within the framework of the EUROfusion Consortium. Starting from the VV space envelope defined in the DEMO baseline design 2014, the layout of the VV structure was preliminarily defined according to the design criteria provided in RCC-MRx. A surface modelling technique was adopted and efficiently linked to the finite element (FE) code to simplify future FE analyses. In view of possible changes to shape and structure during the conceptual design activities, a parametric design approach allows incorporating modifications to the model efficiently.

A Novel Approach to Simultaneous Robust Design of Product Parameters and Tolerances Using Quality Loss and Multivariate ANOVA Concepts

AbstractDesign and development of high quality products are of utmost importance to any production plant. Product design consists of parameter design and tolerance design, which affect the product performances and the manufacturing costs, respectively. Most products involve more than one quality feature. Design and development of such products raise multi‐response surface problems in which it is necessary to determine the optimal values of parameters and the tolerances for all responses simultaneously. In this research, an approach for simultaneous robust parameter and tolerance design is proposed to deal with multi‐response problems. The proposed method employs quality loss concept and one‐way multivariate analysis of variance. Two simulation studies are performed to validate the applicability of the proposed method. Research findings show that the proposed method performs better in quality improvement as well as in cost reduction than the existing methods. The variances of the responses are also lower than those of the other methods, that is, the proposed method results in a more robust approach to product design. Copyright © 2016 John Wiley & Sons, Ltd.