Showing papers in "International Journal of Design Engineering in 2007"

A framework for supporting intelligent and flexible workflow-based engineering design process

Abstract: To support an efficient management of a creative and dynamic Engineering Design Process (EDP), this paper proposes a new intelligent and flexible workflow-based EDP management framework entitled EnDesProM. The Autonomic Object (AO) based on autonomic computing is embedded in the nodes of flexible workflow to ensure the intelligence of the framework. An innovative flexible workflow modelling method based on dynamic instance creation is proposed as part of the EnDesProM. Both the formalised definition and graphical expression of the EDP models are introduced to ensure the rigour of the approach. The architecture of the intelligent workflow is designed and the application of the weighted Certainty Factor (CF) model in the knowledge expression is investigated to deal with the incomplete information in EDP. The EnDesProM has been evaluated through an EDP in a Make-to-Order (MTO) company and the results show that EnDesProM can support the creative and dynamic EDP satisfactorily, though further improvements are required.

Finite element prediction of tool shapes in electro-chemical machining

Abstract: Electro-Chemical Machining (ECM) is one of the most widely used unconventional machining process for machining electrically conducting materials and for machining complex shapes in difficult-to-cut materials without distortion, scratches, burrs and residual stresses. Due to complex nature of ECM process, it is very difficult to predict accurately the shape of the workpiece for the given tool or designing tools to produce required profile in the workpiece. Different techniques have been applied to predict the shape of tool for given shape in the workpiece. In this work, two-dimensional electric potential model is developed for the determination of electric potential distribution in the ECM interelectrode gap. Initially approximate profile 'guess curve' of tool profile is calculated using cosθ method then cumulative current at each node of the tool profile is calculated. Iteration of the guess curve is moved towards exact shape of tool and simultaneously cumulative current on the tool is checked. Iteration is stopped when cumulative current becomes different at each node on the tool profile to get the final shape of the tool.

The 24 hr product: from concept to interactive model in less than a day

Abstract: This paper reports a comparative study on the results of a competitive design project undertaken simultaneously by two multidisciplinary new product development teams in the UK, one based in London and the other in Cardiff, Wales. The project set out to cover the ground from briefing document to the full design and prototyping of an information appliance within 24 hr and to compare and contrast design methodologies employed to complete the challenge. The task was to apply proven design process methodologies to design a device that enhanced communication, knowledge and well-being of target user groups utilising the latest information technology. This paper concentrates on the creativity, design and interface phases of the product development process. In conclusion, this paper compares the strengths and weaknesses of the Cardiff team's interface development methodology, particularly through comparison with the more traditional design approach undertaken by the competing team.

Activities in selecting materials from the perspective of product designers

Abstract: A competitive market requires a materials selection approach that leads to products that stand out in functionality and user-interaction. Insights in how product designers select materials for new products are needed to find ways to optimise these approaches and to train product designers. In this paper, we present the creation of the Material Selecting Activities model (MSA model). This model organises activities product designers currently undertake to determine materials. Similar to general iterative design models, the MSA model shows a cyclic sequence of activities. Subsequent cycles narrow down the search. The MSA model emphasises the existence of three auxiliary activities that support the cycles, namely 'testing materials', 'gathering material information' and 'consulting materials experts'. It is in these activities that product designers depend on external sources in their materials selection approaches. The MSA model forms an effective basis to evaluate and optimise the communication between product designers and these external sources.

A customer?manufacturer?competitor orientation model for product life cycle analysis based on QFD, AHP/ANP and TRIZ

Abstract: With the rapid development of technologies and turbulent market environment, manufacturing industry is challenged with the task of managing products in each stage of Product Life Cycle (PLC). A Customer-Manufacturer-Competitor (CMC) model is developed, which helps manufacturers to analyse customer's, competitor's and manufacturer's orientation and related issues within the PLC. The CMC model consists of three evaluation processes, namely, customer-based evaluation, manufacturer-based evaluation and ideal formulation. In this paper, the characteristics of PLC and the six evaluation sets for assessing the performance of a manufacturer and its competitors in each PLC stage are presented; the advantages of integrating Quality Function Deployment (QFD), Theory of Inventive Problem Solving (TRIZ) and Analytical Hierarchy Process/Analytical Network Process (AHP/ANP) into the CMC model are discussed and then the CMC model is described, followed by a case study illustrating how the CMC model can be applied in the PLC analysis.

Multiobjective design of a vehicular structure using metamodelling and an efficient genetic algorithm

Abstract: A new Non-dominated Sorting (NS) algorithm is presented in this paper to improve the efficiency of Genetic Algorithms (GAs) in solving multiobjective optimisation problems. Commonly used NS algorithms typically have a time complexity of O(MN?) to obtain a set of N non-dominated solutions for M objectives. In the proposed NS algorithm, a new dominance tree structure and a divide-and-conquer mechanism are adopted to reduce the number of redundant comparisons in determining non-dominated solutions. The new algorithm is implemented into Non-dominated Sorting Genetic Algorithm (NSGA)-II and shown to have improved overall efficiency of the entire evolution processes. By combining with the metamodelling technique, the new algorithm is successfully used in the multiobjective design of a vehicular structure for safety improvement and weight reduction.