Xiu-Tian Yan

Integrated product relationships management: a model to enable concurrent product design and assembly sequence planning

The paper describes a novel approach to product relationships management in the context of concurrent engineering and product lifecycle management (PLM). Current industrial practices in product data management and manufacturing process management systems require better efficiency, flexibility, and sensitivity in managing product information at various levels of abstraction throughout its lifecycle. The aim of the proposed work is to manage vital yet complex and inherent product relationship information to enable concurrent product design and assembly sequence planning. Indeed, the definition of the product with its assembly sequence requires the management and the understanding of the numerous product relationships, ensuring consistency between the product and its components. This main objective stresses the relational design paradigm by focusing on product relationships along its lifecycle. This paper gives the detailed description of the background and models which highlight the need for a more efficient PLM approach. The proposed theoretical approach is then described in detail. A separate paper will focus on the implementation of the proposed approach in a PLM-based application, and an in-depth case study to evaluate the implementation of the novel approach will also be given.

Product relationships management enabler for concurrent engineering and product lifecycle management

The current competitive industrial context requires more flexible, intelligent and compact product lifecycles, especially in the product development process where several lifecycle issues have to be considered, so as to deliver lifecycle oriented products. This paper describes the application of a novel product relationships management approach, in the context of product lifecycle management (PLM), enabling concurrent product design and assembly sequence planning. Previous work has provided a foundation through a theoretical framework, enhanced by the paradigm of product relational design and management. This statement therefore highlights the concurrent and proactive aspect of assembly oriented design vision. Central to this approach is the establishment and implementation of a complex and multiple viewpoints of product development addressing various stakeholders design and assembly planning points of view. By establishing such comprehensive relationships and identifying related relationships among several lifecycle phases, it is then possible to undertake the product design and assembly phases concurrently. Specifically, the proposed work and its application enable the management of product relationship information at the interface of product-process data management techniques. Based on the theory, models and techniques such as described in previous work, the implementation of a new hub application called PEGASUS is then described. Also based on web service technology, PEGASUS can be considered as a mediator application and/or an enabler for PLM that externalises product relationships and enables the control of information flow with internal regulation procedures. The feasibility of the approach is justified and the associated benefits are reported with a mechanical assembly as a case study.

Exploring decisions' influence on life-cycle performance to aid “design for Multi-X”

The problem addressed in this paper is that design decisions can have a propagation effect spanning multiple life-phases influencing life-cycle metrics such as cost, time, and quality. It introduces a computational framework of a “Knowledge of life-cycle Consequences (KC) approach” aimed at allowing designers to foresee and explore effectively unintended, solution specific life-cycle consequences (LCCs) during solution synthesis. The paper presents a phenomena model describing how LCCs are generated from two fundamentally different conditions: noninteracting and interacting synthesis decision commitments. Based on this understanding, the KC approach framework has been developed and implemented as a Knowledge-Intensive CAD (KICAD) tool named FORESEE. The framework consists of three frames: an artefact life modelling frame, an operational frame, and an LCC knowledge modelling frame. This paper focuses on the knowledge modelling frame, composed basically of synthesis elements, consequence inference knowledge, and consequence action knowledge. To evaluate the influence of design decision consequences on artefact life-phases, cost, time and quality performance measures are used within the frame. Using these metrics, the life-cycle implications of a decision can be instantly updated and fully appreciated. An evaluation of the approach was carried out by applying FORESEE to thermoplastic component design. The results provide a degree of evidence that the approach integrates the activity of component design synthesis with the activity of foreseeing artefact life issues including fluctuations in life-cycle metrics. This makes the approach fundamentally different from the conventional approach in which first a candidate design solution is generated and then, at a penalty of extra time, an analysis of the solution for conflicts with artefact life issues is carried out. The framework thus provides a significant step towards the realization of a “Design Synthesis for Multi-X” approach to component design, although further work is required to exploit practically its utilization.

Guiding component form design using decision consequence knowledge support

This paper describes a generic approach to guiding designers when making decisions during the early stages of design. The objective of the research is to enable designers to foresee unintended life-cycle consequences during mechanical component design. Engineering design is a process of evolving solutions to a design problem through the commitment of decisions. As a designer commits a new design decision, a more concrete design solution is generated. Decisions made can have intended and unintended consequences on the performance of the life phase activities that follow, such as manufacturing, assembly, and disposal. Many existing tools only consider the impact of the design solution on later life-cycle phases when the solution is almost complete. This makes changes expensive and difficult. This paper presents a novel approach to how consequences encountered in down stream life-cycle phases can be brought to the designers attention early in generation of component form. For this purpose, a knowledge model has been derived from a phenomena model. The phenomena model describes how life-cycle consequences are generated during component synthesis. An insight into the representation of the resultant knowledge model is discussed through examples. The implementation of a prototype Knowledge Intensive CAD tool, entitled FORESEE, aimed at supporting life-oriented, feature-based component synthesis and exploration, is also described. The results of the evaluation of FORESEE with a range of designers show that by using the system designers are motivated to explore alternative design solutions and are able to make more informed design decisions. This highlights that the knowledge structure provides a base for extending feature-based component design to a ‘Design Synthesis for Multi-X’ approach.

A Theoretical and Experimental Study on Characteristics of Water-Lubricated Double Spiral–Grooved Seals

The spiral-grooved seal is a prime candidate for application to liquid oxygen (LOX) turbopumps. A theoretical model of double spiral–grooved seals dealing with the viscosity–temperature relation is presented. The effect of operating parameters (rotational speed, supply pressure) and configurative parameters (depth of spiral groove) on the basic static characteristics (opening force, leakage, static friction torque, face temperature, and power loss) of double spiral–grooved seals are examined. Comparisons are presented between measurements and theoretical predications for a narrow spiral-grooved face seal with an average diameter of 100 mm, operating at high speed and using water as a test fluid. The theoretical and experimental results indicate that the temperature on seal faces rises and friction torque increases with the speed and supply pressure, and these increases vary slightly with the depth of the spiral groove. These findings lend great theoretical and experimental insights to the design of face seals applied in liquid engine turbopumps.

Global Design to Gain a Competitive Edge

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Advanced Design and Manufacture to Gain a Competitive Edge

The globalization of manufacturing industries leads to a thirst for rapid advancements in technological development and expertise in advanced design and manufacturing. Both industry and academia have an urgent need to equip themselves of the latest knowledge and trends relating to design and manufacture. Advanced Design and Manufacture to Gain a Competitive Edge collects together papers from the 2008 International Conference on Advanced Design and Manufacture (ICADAM). This conference solicits both cutting edge fundamental research and recent industrial application papers, with a goal towards bringing together from all over the world design and manufacture practitioners from academia, government organizations and industry. Recent advancements, emerging trends and new challenges in the fields of design and manufacturing are covered, with a particular focus on the understanding of the impact of distributed team-based design and manufacture on research and industrial practices for global companies.

Evaluation of the Thermodynamic Data of CH3SiCl3 Based on Quantum Chemistry Calculations

CH3SiCl3 (methyltrichlorosilane) (MTS) is one of the most important precursors for manufacturing both an oxidation resistant SiC coating and a functional SiC film by chemical vapor deposition (CVD). In order to analyze the decomposition products of MTS with a thermodynamic calculation, correct thermodynamic data must be obtained from the authoritative data sources. G3(MP2) has been applied to evaluate the thermodynamic data of MTS(gas). The calculated value of the Gibbs energy of formation, ΔfGm0(298.15K)=−490.13kJ∙mol−1, compares with a value, ΔfGm0(298.15K)=−468.02kJ∙mol−1 from the 4th edition of the NIST-JANAF Thermochemical Tables. Further analyses have been conducted: (1) by using G3, G3//B3LYP, and G3(MP2)//B3LYP theories; (2) by using variable scale factors for G3(MP2) theory; and (3) by investigating the accuracy of both experimental and calculated thermodynamic data. The calculated values can provide ΔfGm0 values for MTS above 1500K. The final fitted equation for MTS(gas) is: ΔfGm0=7.5763×10−6T2+...

Supporting early design decision making using design context knowledge

The decisions made at conceptual design are crucial to the overall success of a product as they affect all the downstream phases of the product life-cycle, user satisfaction of the product and the environment in which the product is to be used and disposed of. Owing to a lack of availability of knowledge and understanding about the complexity of such knowledge spanning these different life phases, designers find it difficult to foresee the implications or consequences of their decisions made at conceptual design on the products life-cycle, its users and its operational environment. This paper explores the true meaning of design context knowledge by studying how these pieces of knowledge can be formalised and, more importantly, how they can be used in a structured way to support decision making and the prediction of their consequences at the conceptual design stage. A case study is presented to illustrate the strengths of this approach, followed by formal evaluations of the approach and a prototype system developed in this research.

A framework for supporting multidisciplinary engineering design exploration and life-cycle design using underconstrained problem solving

The problem investigated in this research is that engineering design decision making can be complicated and made difficult by highly coupled design parameters and the vast number of design parameters. This complication often hinders the full exploration of a design solution space in order to generate optimal design solution. These hindrances result in inferior or unfit design solutions generated for a given design problem due to a lack of understanding of both the problem and the solution space. This research introduces a computational framework of a new algebraic constraint-based design approach aimed at providing a deeper understanding of the design problem and enabling the designers to gain insights to the dynamic solution space and the problem. This will enable designers to make informed decisions based on the insights derived from parameter relationships extracted. This paper also describes an enhanced understanding of an engineering design process as a constraint centered design. It argues that with more effort and appreciation of the benefits derived from this constraint-based design approach, engineering design can be advanced significantly by first generating a more quantitative product design specification and then using these quantitative statements as the basis for constraint-based rigorous design. The approach has been investigated in the context of whole product life-cycle design and multidisciplinary design, aiming to derive a generic constraint-based design approach that can cope with life-cycle design and different engineering disciplines. A prototype system has been implemented based on a constraint-based system architecture. The paper gives details of the constraint-based design process through illustrating a worked real design example. The successful application of the approach in two highly coupled engineering design problems and the evaluation undertaken by a group of experienced designers show that the approach does provide the designers with insights for better exploration, enabled by the algebraic constraint solver. The approach thus provides a significant step towards fuller scale constraint-based scientific design.