Initial Conceptual Design Research Articles

English

Redundancy-reliability allocation problems in multi-stage series-parallel systems under uncertain environments are addressed in this study. First, a multi-objective programming model is formulated for simultaneously maximizing system reliability and minimizing system total cost. Due to the nature of uncertainty in the problem, the fuzzy set theory and technique are used to convert the deterministic multi-objective programming model into a fuzzy nonlinear programming problem. A heuristic method is developed to get a set of satisfactory solutions for the fuzzy nonlinear programming problem. Then, a modified data envelopment analysis (DEA) model, is applied for completely ranking those satisfactory solutions considering some criteria of satisfactory, reliability, cost, volume and weight. A case study that is related to the electronic control unit installed on aircraft engine over-speed protection system is used to implement the developed approach. Results suggest that the developed fuzzy programming and DEA approach can effectively resolve the fuzzy and uncertain problem when design goals and constraints are not clearly confirmed at the initial conceptual design phase.   Key words: Fuzzy programming, data envelopment analysis, reliability allocation.

2P1-M02 クルー装着型マニピュレータの初期概念検討 : 概念設計とロボットハンドの試作(【宇宙工学部門】宇宙工学とロボティクス・メカトロニクス)

This paper presents an initial conceptual design of a wearable manipulator for supporting astronaut extravehicular activity (EVA). The proposed robot system acts as a third hand or eye of astronauts, and supports them by handling tools or recording their tasks using camera during EVA with the manipulator itself attached to the space suit or handrail. The initial conceptual design includes the system concept, requirements, elemental technologies and operational scenarios which are defined on the basis of the interviews to astronauts and operators. The prototype of the manipulator, especially robotic hand or end effector is also discussed in this paper for estimating the feasibility of the proposed robot system in the future manned space activities.

Identifying design development factors in Australian PPP projects using an AHP framework

In Australia consortiums will come together and create an initial design concept or sketch design at the public–private partnership (PPP) bid stage. If the bid is successful this initial design is then developed further. However, a winning bid may have been evaluated on financial criteria alone and the consortium’s capability to develop the design through to project delivery may not have been thoroughly evaluated. In theory, design is a key process in PPP projects and the aim of the research was to understand what capabilities are important in the development of a design through this process. To clarify these issues, a range of activities and organizational factors linked to design development are proposed using the analytic hierarchy process (AHP) method. This method was chosen in order to see which design development factors were ranked more highly by experts. In this research the hierarchy was designed employing the categories of exploratory and exploitative design development. Below each of these overarching categories, there were four design development functional distinctions: the two exploratory distinctions were Design (D) and Design Management (DM). The two exploitative distinctions were Design Support (DS) and Design Infrastructure (DI). A further list of 36 design development sub-criteria was developed under the above categories. These sub-criteria formed the basis of a survey of respondents drawn from a database of industry sources in the public domain as well as a list gathered from a large developer involved in PPP projects. It included relatively senior managers, PPP project managers and architects. Survey respondents identified a recent PPP project that they had worked on. From the 36 responses it can be seen that the exploratory Design (D) and Design Management (DM) activities were ranked more highly than the exploitative activities of Design Support (DS) and Design Infrastructure (DI) associated with a PPP project organization. This suggests that PPP frameworks should account for these exploratory factors as well as the exploitative factors associated with compliance, quality systems and project team infrastructure. This indicates that in PPP projects design development through the effective management of an initial design is a critical factor.

Cracking Behavior of Continuously Reinforced Concrete Pavements in Belgium

Continuously reinforced concrete pavements (CRCPs) have been used in Belgium on a large scale for more than 40 years. Under the initial standard design concept, an apparently unfavorable cracking pattern develops with a high probability of clusters of closely spaced cracks. The standard design underwent several changes addressing longitudinal reinforcement rate, depth of the reinforcement layer, presence of an asphalt interlayer, pavement thickness, concrete mix, surface finishing, and lane width. The current concept has been used since 1995, and no major distresses have occurred since then. Research was undertaken to investigate crack spacing and crack width characteristics of CRCPs under the current design concept with a focus on the influence of the differing reinforcement percentages on early-age cracking behavior of CRCPs. Several approaches were used for analysis of crack spacing, especially the probability of clusters of closely spaced cracks. Crack width data including the movement of the slab were obtained with linear variable differential transformer measurements.

Integrating shape grammars into a generative system for Zhuang ethnic embroidery design exploration

The integration of shape grammars within a generative system is thought to have good potential to support design applications in the art and cultural domains. Based on a shape decomposing method, two-level generative shape grammars are developed within the application of Zhuang ethnic embroidery design. In our approach, free B-spline curves are used to derive initial design concepts together with a new interpolation algorithm. In order to cope with the potentially huge solution space, a novel aesthetic evaluation model and a design exploration algorithm are developed for designers to find their favorite design solutions based on their subjective assessments. A system is introduced to demonstrate this research with an example of Zhuang ethnic embroidery design.

Layout optimization method for magnetic circuit using multistep utilization of genetic algorithm combined with design space reduction

Layout optimization with ON/OFF information of magnetic material in finite elements is one of the most attractive tools in the initial conceptual and practical design of electrical machinery for engineers. Heuristic algorithms based on random search allow engineers to define general-purpose objects. However, there are many iterations of finite element analysis, and it is difficult to achieve a practical solution without island and void distribution by using a direct search method, such as simulated annealing (SA), genetic algorithm (GA), and so on. This paper presents a layout optimization method based on GA. The proposed method can arrive at a practical solution by means of multistep utilization of the GA, and the convergence speed is considerably improved by using it in combination with reduction of the design space. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(3): 19-30, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22290

Progress on NSTX center stack upgrade

The national spherical torus experiment (NSTX) will be upgraded to provide increased toroidal field, plasma current and pulse length. This involves the replacement of the so-called center stack, including the inner legs of the toroidal field (TF) coil, the Ohmic heating (OH) coil, and the inner poloidal field (PF) coils. In addition the increased performance of the upgrade requires qualification of remaining existing components for higher loads. Initial conceptual design efforts were based on worst-case combinations of possible currents that the power supplies could deliver. This proved to be an onerous requirement and caused many of the outer coils support structures to require costly heavy reinforcement. This has led to the planned implementation of a digital coil protection system (DCPS) to reduce design-basis loads to levels that are more realistic and manageable. As a minimum, all components must be qualified for the increase in normal operating loads with headroom. Design features and analysis efforts needed to meet the upgrade loading are discussed. Mission and features of the DCPS are presented.

Topological Design for 3-D Optimization Using the Combination of Multistep Genetic Algorithm with Design Space Reduction and Nonconforming Mesh Connection

Topology optimization, which identifies the optimal combination of ON-OFF material, is one of the most attractive tools in the initial conceptual and practical design of electrical machineries for engineers. Heuristic optimization algorithms based on the random search flexibly allow the engineers to define the objective function. However, there are huge iterations of finite element analysis in 3-D topological optimization according to many design variables. It is difficult to show the practical solution without the island and void distributions. This paper presents the 3-D topological optimization method based on multistep utilization of GA. Proposed method can obtain a practical solution, and the convergence is remarkably improved by the design space reduction. Furthermore, the elapsed time for 3-D optimization can be more reduced to a quarter of conventional analysis by the combination of nonconforming mesh connection.

고해상도 SAR 최적 설계를 위한 영상형성 시스템 변수 및 성능분석에 관한 연구

합성 개구면 레이다(SAR: synthetic aperture radar)는 날씨 및 주 야간에 관계없이 고해상도의 영상을 형성할 수 있기 때문에 다양한 분야에서 활용되고 있다. 본 논문에서는 고해상도 SAR 설계시 경사거리와 합성개구면의 길이가 영상형성에 미치는 영향을 RMA 시뮬레이터를 이용하여 성능분석을 수행하였다. 형성된 영상의 성능은 직접 육안으로 확인할 수 있었으나, 영상을 분석하는 수치로서도 성능평가가 가능하였다. 보다 구체적으로, 다양한 경사거리와 합성개구면의 길이 변화와 영상획득을 위한 기하구조에 따라 이상적인 점표적에 대한 시뮬레이션의 원시 데이터를 생성하였고, Spotlight 영상 형성 알고리듬을 이용하여 이에 따른 점표적 응답특성의 공간 해상도, 최대 부엽 수준, 누적 부엽 수준에 대한 성능분석을 수행하였다. Synthetic aperture radar (SAR) has been employed in various fields due to its capability to generate high resolution images regardless of weather and visibility. This paper presents a performance analysis on the image formation of high resolution SAR according to various slant range distance and synthetic aperture lengths using a range migration algorithm simulator. Although the visual performance on the SAR image is more accurate, a numeric analysis resulted in a comparable measurement. More specifically, raw data were generated for an ideal point target upon imaging geometries and design parameters such as slant range distance and synthetic aperture lengths. Finally, spatial resolution, peak to sidelobe ratio and integrated sidelobe ratio are drawn to provide SAR capabilities in the initial concept design, final in-flight calibration and validation stages.

Efficacy, Safety, and Palatability of RACTAB® Formulation Amlodipine Orally Disintegrating Tablets

Objective: The aim of this study was to confirm the efficacy, safety, and expected palatability of amlodipine orally disintegrating tablets (ODT) [RACTAB® formulation (Towa, Osaka, Japan)]. We report the re-analyzed results of 1687 cases in clinical settings obtained through postmarketing surveillance in Japan. Method: Study subjects were patients receiving treatment for the first time with amlodipine ODT for hypertension under routine care. A multicenter central registration system was used for this prospective survey. The survey was conducted from October 2008 to October 2010. The observational period was 12 weeks, during which time surveys on outpatient blood pressure, adverse events, palatability, etc. were conducted. Results: Blood pressure stabilized following treatment, and both systolic and diastolic blood pressures were favorably controlled. Adverse events observed were not significantly different from those observed during drug use trials of amlodipine formulations reported in 2003. Moreover, palatability of amlodipine ODT showed a 99.6% (227 of 228 cases) favorable patient acceptance, which is consistent with the initial design concept of RACTAB® formulation. Conclusions: The results of this postmarketing surveillance study indicated that the efficacy, safety, and palatability of amlodipine ODT met our expectations (dissolves quickly in the mouth, tastes good, and is not rough on the tongue). Accordingly, amlodipine ODT are believed to be an easy-to-use formulation for prescribing doctors, dispensing pharmacists, and patients receiving treatment.

Efficacy, safety, and palatability of RACTAB(®) formulation amlodipine orally disintegrating tablets.

Objective: The aim of this study was to confirm the efficacy, safety, and expected palatability of amlodipine orally disintegrating tablets (ODT) [RACTAB® formulation (Towa, Osaka, Japan)]. We report the re-analyzed results of 1687 cases in clinical settings obtained through postmarketing surveillance in Japan.Method: Study subjects were patients receiving treatment for the first time with amlodipine ODT for hypertension under routine care. A multicenter central registration system was used for this prospective survey. The survey was conducted from October 2008 to October 2010. The observational period was 12 weeks, during which time surveys on outpatient blood pressure, adverse events, palatability, etc. were conducted.Results: Blood pressure stabilized following treatment, and both systolic and diastolic blood pressures were favorably controlled. Adverse events observed were not significantly different from those observed during drug use trials of amlodipine formulations reported in 2003. Moreover, palatability of amlodipine ODT showed a 99.6% (227 of 228 cases) favorable patient acceptance, which is consistent with the initial design concept of RACTAB® formulation.Conclusions: The results of this postmarketing surveillance study indicated that the efficacy, safety, and palatability of amlodipine ODT met our expectations (dissolves quickly in the mouth, tastes good, and is not rough on the tongue). Accordingly, amlodipine ODT are believed to be an easy-to-use formulation for prescribing doctors, dispensing pharmacists, and patients receiving treatment.

A new hip epiphyseal prosthesis: Design revision driven by a validated numerical procedure

An innovative epiphyseal device has been recently proposed claiming an effective bone–prosthesis load transfer and a nearly physiological bone stresses distribution. However preliminary experimental tests showed a 23% weakening of the femoral neck after implantation. Aim of this study was to revise the prosthesis geometry with the goal of enhancing the femoral neck strength after implantation, while maintaining unchanged the initial conceptual design. To this aim, the risk of femoral neck fractures, prosthesis fractures, aseptic loosening and excessive bone resorption were addressed through a validated finite element procedure following a systematic approach. The initial prosthesis geometry was revised to reduce each investigated failure risk below the threshold of acceptance (100%). The new geometry was re-assessed to verify the effectiveness of the revision. The first design was predicted to locally induce high bone strains and cement stresses, which translated in a risk of bone and cement failure exceeding the threshold of acceptance (>100%). The revised design preserved a good stability of the device, contemporary reducing the risk for bone (45%) and cement (60%) failure. If results will be confirmed by statistical and clinical experimentations, current clinical indications for hip epiphyseal devices might be extended.

ITER Remote Maintenance System (IRMS) lifecycle management

The availability of the ITER machine to perform its scientific program is strongly dependent on the performance of the different Remote Handling (RH) systems constituting the ITER Remote Maintenance System (IRMS). The lifecycle of the IRMS will largely exceed 40 years from initial concept design and proof testing through to machine decommissioning. Such a long lifecycle requires that a rigorous approach is put in place to guarantee the technical capabilities of the highly innovative IRMS, its efficiency and its availability. For this purpose, an IRMS System Engineering and IRMS lifecycle management approach has been adopted by ITER. The approach aims at ensuring the IRMS full operability and availability at an acceptable cost of ownership over the full ITER machine assembly and operations period. The IRMS lifecycle management method described in this paper covers such subjects as specific requirements for IRMS design reviews, monitoring during manufacture, factory and site acceptance testing, integrated commissioning, decontamination, maintenance and re-qualification strategies, requirements for Integrated Logistical Support during operations. The updating and implementation of the IRMS lifecycle strategy and this procedure will be managed and monitored by the Remote Handling Integrated Product Team (RH-IPT). Although developed for the IRMS, the basic principles and procedures of lifecycle management could be applied to other ITER plant systems whose reliability and availability will be essential for the continued operation of the ITER machine.

Railroad passenger car collision analysis and modifications for improved crashworthiness

In this study, crashworthiness assessment and suggestions for the modification of a railroad passenger car are presented. To assess the crashworthiness, collision of the railroad passenger car onto a rigid wall is simulated by using finite element (FE) methods. A full-length, detailed passenger car model is used in FE analyses. In order to validate the FE model, simulation results obtained for different types of static loading conditions in compliance with various scenarios defined in UIC CODE OR 577 are compared with experimental measurements before running collision analyses of the railroad passenger car. The good agreement between static tests and FE analyses results indicates that the FE model accurately represents the real structure. Following the FE model validation, analysis of the collision behaviour of the railroad passenger car consists of two stages. In the first stage, the crashworthiness of the initial concept design of the railroad passenger car is analysed. It was observed that local buckling takes place at various points, which prevents the desired progressive damage behaviour in the railroad car body. Having revealed the structural weaknesses, the initial design was modified and simulated again under the same conditions. Using size optimisation, thickness of some sheet metal components is changed in order to obtain the intended progressive damage behaviour. As a result of the modifications, the passenger car design with better crashworthiness properties was obtained, in which large plastic deformations occur around the collision side of the car while mainly elastic deformations occur in the car's body away from the bumpers.

RMA를 이용한 Spotlight SAR 영상형성 및 품질평가를 위한 시뮬레이터 개발 및 구현

합성 개구면 레이다(SAR: synthetic aperture radar)는 날씨 및 주/야간에 관계없이 고해상도의 영상을 형성할 수 있기 때문에 다양한 분야에서 활용되고 있다. 본 논문에서는 영상 형상 및 품질 평가, 분석을 위한 Spotlight SAR 시뮬레이터를 제안한다. SAR 영상 품질의 예측은 초기 개념 설계 단계부터 최종적인 비행 검증 및 보정 단계에 걸쳐 필수적이다. 제안된 SAR 시뮬레이터는 시스템 설계 변수들에 기반을 두고 있어 전체 시스템 개발과정에서 SAR 영상의 품질을 예측 분석할 수 있다. 이를 위해 영상 획득 기하구조와 다양한 SAR 시스템 설계변수들을 고려하여 이상적인 점표적에 대한 시뮬레이션 원시 데이터를 생성하고 Spotlight 영상 형성 알고리듬을 구현함으로서 점표적 응답특성을 추정한다. 마지막으로 공간 해상도, 최대 부엽 수준, 누적 부엽 수준 등의 주요 품질변수들을 중심으로 생성된 원시 데이터의 영상 품질을 분석한다. Synthetic aperture radar (SAR) is widely used because of high resolution imaging capability in all weather and day/night condition. In this paper development of Spotlight SAR simulator is proposed for image quality analysis. Proposed SAR simulator is based on the SAR system design parameters so that SAR image performance can be expected which is essential throughout the full system development procedure from the initial concept design stage to the final in-flight calibration and validation stage. The raw data of ideal point target is first generated by taking account of the flight and imaging geometry and the various SAR system design parameters, and the Spotlight image formation algorithm is implemented in order to obtain the point target response. Finally the image quality of the generated raw data is analyzed in terms of spatial resolution, peak to sidelobe ratio and integrated sidelobe ratio.

Layout Optimization Method for Magnetic Circuit using Multi-step Utilization of Genetic Algorithm Combined with Design Space Reduction

The layout optimization with the ON-OFF information of magnetic material in finite elements is one of the most attractive tools in initial conceptual and practical design of electrical machinery for engineers. The heuristic algorithms based on the random search allow the engineers to define the general-purpose objects, however, there are many iterations of finite element analysis, and it is difficult to realize the practical solution without island and void distribution by using direct search method, for example, simulated annealing (SA), genetic algorithm (GA), and so on. This paper presents the layout optimization method based on GA. Proposed method can arrive at the practical solution by means of multi-step utilization of GA, and the convergence speed is considerably improved by using the combination with the reduction process of design space.

Integrated Design and Control of Flexure-Based Nanopositioning Systems — Part I: Methodology

AbstractFlexure-based mechanisms, also referred to as flexures, are widely being used as motion-guidance, or bearing, elements in applications requiring multi-degree-of-freedom positioning and alignment. Unlike friction-bearings (such as sliding or rolling contact bearings), flexures can be designed to offer, to a large extent, reliable linear elastic motion with a high resolution (on the order of nanometers) over small ranges of motion (on order of micrometers). Example applications include positioning a probe or sample in atomic force microscopy, alignment of tool and sample in stamping processes, and fine-positioning of wafers and masks in semiconductor manufacturing. These applications are often required satisfy critical functional requirements, such as load-capacity, bandwidth, resolution, and range. A systematic approach is needed to simultaneously address the design and control challenges involved, starting from the initial design concept generation stage to the final control implementation and testing. In this paper, we present an integrated design and control method for implementing flexure-based nanopositioning systems. We discuss the need for varying design topology and order of a controller in design and control optimization. An automation engine generates a set of flexure-based design topologies and also controllers of varying order in the optimization. A simple 1-DOF example is worked out to illustrate the steps involved in using this methodology. The outcome of the exercise is a novel design topology, with it shape and size optimized, and a controller synthesized such that a desired control bandwidth and design requirements of strength and modal separation are met.

Examination of Optimal Design of IPM Motor Using ON/OFF Method

The topology optimization by distributing the magnetic material in the design domain, which is called as the ON/OFF method, is attractive for designers of magnetic devices, because an initial conceptual design, that we could not imagined beforehand, may be obtained. We examined how to apply the ON/OFF sensitivity method to the IPM (Interior Permanent Magnet) motor in order to determine the optimal topology of the rotor. A technique to apply the ON/OFF method to the design of motor considering the nonlinearity of B-H curve and rotation of rotor is shown. The effects of the choice of the design region and the phase angle of stator current on the obtained topology of motor core are discussed.

A Holographic Antenna Approach for Surface Wave Control in Microstrip Antenna Applications

A holographic antenna inspired structure is used to control the surface wave (SW) excited by a microstrip patch antenna. The hologram is designed to support a periodic leaky-wave which radiates at broadside and enhances the radiation of the patch while suppressing the horizontal lobe. In this design, the holographic approach is adapted for patch antenna applications where the SW wavelengths are comparable to the freespace wavelength. This is achieved by introducing dual phase-shifting metallic dipoles with periodic spacings. This paper discusses a simple and intuitive design method for the holographic surface, as well as its integration with the microstrip patch. The initial design concept was developed by assuming small perturbation to the SW, which was subsequently verified through full-wave simulations and prototype measurements. The results verified the improvements in the broadside gain and SW efficiency of the microstrip patch at the cost of increased area.

Exoskeleton Solutions to Bone and Muscle Atrophy Within Microgravity Environments

Weakening of muscle and bone tissue after merely a week of exposure to a microgravity environment has been demonstrated to adversely affect the physiological health of astronauts . Innovative solutions meant to replace traditionally bulky resistance-based devices are highly sought by burgeoning private space travel companies as well as other ambitious spaceflight programs that require a robust and effective solution for long durations in microgravity . The purpose of this study is to explore the unique contributions of exoskeleton technology in providing an effective, compact and elegant preventative device through assessing the current ability of exoskeleton technologies in stressing the body, formulating design requirements of an exoskeleton device and highlighting the areas of exoskeleton development that require further work in the realization of a robust microgravity-atrophy solution. An understanding of the abilities and shortcomings of current exoskeleton technologies is necessary to develop and streamline advanced forms of today's space physiological devices . The physiologically familiar structure of an exoskeleton, being built around the human form, would also provide for a greater degree of compactness, affecting everything from launch expenses to living arrangements in any space module. A more effective and persistent method of stressing the body will ultimately allow for a drastic decrease in bone and muscle atrophy, requiring less therapy should any space traveler return to a gravity environment as well as preventing various related ailments during their time in space. In conducting the study, a literature search was performed to identify fundamental design parameters. Designs were then formulated to best fit the required design specifications with difficult or absent features being noted. Initial design concepts based on traditional resistance-based solutions were also developed to further characterize the particular requirements that an exoskeleton would be required to fulfill. These design concepts were then steadily revised into a potential force generation mechanism and device architecture based on factors including human comfort, force generation, effective ranges of motion, materials and geometry. An appraisal of current exoskeleton technology in actualizing the proposed designs and design specifications provides a basis for analysis. The study has uncovered the strong points in exoskeletal designs as well as the major hurdles that, once crossed, will allow exoskeletal technologies to be a viable application in bone and muscle therapies, both in microgravity environments as well as gravity environments. A large hurdle lies in current exoskeleton technologies still utilizing bulky components but past trends have demonstrated a reliable miniaturization in the technology. Particularly important exercises and ranges of motion have been identified and initial designs formulated based on the physiological requirements. The study has demonstrated the need for more efforts in formulating innovative solutions to space-based physiology problems as well as explicitly listing design parameters required for any potential exoskeleton solution.