The Green Browser: An Information Sharing Tool for Product Life Cycle Design

This paper presents the concept and implementation of the Green Browser, which enables designers and consumers to share environmental information. We propose the conceptual scheme of the Green Browser called green life cycle model. This model is intended to represent the product’s environmental impacts over the stages of raw materials, use, recycling, and disposal. The Green Browser has been implemented using WWW and MOO to be able to deal with the strategy model, which is the key element of the green life cycle model. A case study on building the strategy model of refrigerator is presented to illustrate the strategy model.

Catalogue Design of Technical Systems Based on a Resource Exchange Paradigm

In this paper, we illustrate the use of the resource exchange paradigm for mechanical systems and, through multi-level configuration, for complex systems. To make this paper self-contained, a short introduction to resource-based modelling is included.

Constraint Management Methodology for Conceptual Design Tradeoff Studies

This paper presents a constraint management methodology, which facilitates tradeoff studies during conceptual design. This approach represents design models as constraints between variables, and uses the resulting constraint network to automatically derive computational procedures for performing user-specified tradeoff studies. By decomposing large constraint networks into smaller pieces that can be solved robustly, this approach can solve extremely large systems of non-linear equations present in practical system models. Design Sheet is a software implementation of this methodology; it allows the designer to interactively develop models, flexibly define tradeoff studies, and quickly explore large areas of design space to study how the different performance and cost criteria tradeoff with respect to one another. Design Sheet has been used on practical applications ranging from the system-level design of spacecraft using combined performance and cost models to the preliminary design of automotive bearings. This paper demonstrates the unique capabilities of Design Sheet in performing design tradeoff studies, using a thermal imaging system performance model developed for the DARPA MADE program.

Team-Roles in Mechanical Design

This paper presents an approach for identifying team-roles. The proposed approach is based on the interpretation of a design process in terms of the behavior of the members of the team. Behavior is codified in terms of the team member’s process and physical activities. In this study a collaborative design process was recorded on video-tape and analyzed in detail. The process was decomposed into distinct sections called events. In every event each team member was assigned a team-role taking into consideration the activity of the team member, i.e. what the team member does, how activity of the team member, i.e. what the team member does, how the team member does it, and the context of the event. A graphical representation of the results called ‘role-profile’ was developed making it possible to clearly identify a basic team-role for every subject in the observed design process.

Dependence of Early Engineering Concepts on Information Characteristics

The expectations of computer tools to support the conceptual design phase are not yet met. An experimental approach to discover the use of information in conceptual design will give a realistic insight of the information requirements. This can be used to specify future computer support systems. A method to observe the use of information in a conceptual design process has recently been developed. The method has been tested and fine-tuned through the observation of 10 design sessions. Valuable empirical data resides from this experiment. Data has been analyzed in several perspectives. This paper presents the results of the activity/information analysis of the experiment in relation with the quality of the design concept. For the latter a rating system has been defined to quantify this. We have found a significant positive correlation of the amount of information that is communicated and the quality of the design. Furthermore a discussion is given on the relation between information and the activities of the designer. Analysis activities are more communication intensive compared to synthesis and evaluation tasks.

Configuration Design: An Integrated Approach Using Grammars

A computational approach to design that integrates conceptual design, configuration design, and catalog component selection tasks overcomes some of the barriers to successful design automation. FFREADA is a design generation and optimization algorithm featuring hierarchical ordering of grammar based-design generation processes at different levels of abstraction. FFREADA is used to design hand-held, power drills and to develop an appropriate objective function for design optimization. The drill grammar expresses a vast space of design states that are not limited to any particular functional architecture or component configuration. (The algorithm’s optimization runs operate in a space which exceeds 20249 designs.) Good drill designs, those with values within 1% of the optimal solution, are found in minutes by sampling less than 0.15% of the design states. Optimal configurations are found for drills with three different torque requirements.

Forming Product Design Specifications

Design teams commonly form quantitative functional specification lists that define performance targets for a product. Meeting these specifications ensures that the customer needs are satisfied. A central difficulty is to identify the relevant metrics to use as specifications. A working methodology is presented here to establish relevant, quantitative, measurable performance specifications. To start, customer needs, their importances, and the customer use patterns are gathered for the product. Voice-of-the-customer methods are augmented to distinguish no-compromise constraints that must be met. Next, a design is analyzed to establish a representative function structure, applying Pahl and Beitz’s systematic design approach. An optimal function structure can now be defined by a condition of simultaneous maximum simplicity and comprehensive coverage of the gathered customer needs. The function structure can then be used as a list over which specifications are to be made, with at least one specification per sub-function. Having a rational function structure allows a team to more easily determine variables on which to make specifications. A team can then use the House of Quality to document and form consensus over these specifications in the typical way.

Design for Assembly Techniques in Reverse Engineering and Redesign

Design for Assembly (DFA) is the process by which a product is designed to be easily assembled. Such design simplifications are accomplished through reducing the number of operations required to assemble the product, improving the handling of each component, and/or modifying the required operations (insertion, joining, etc.). There exist several techniques for assessing the assemblability of a design through an analysis of these three aspects. However, there also exists a clearly defined need for evolving such techniques to indicate how a product should be redesigned with respect to customer needs and associated functionality. This paper presents three such evolutions, aimed at reducing the number of components in an assembly during redesign. The first technique is a component elimination procedure, the second technique is a component combination analysis, and the third technique establishes a logical approach for revealing more abstract component elimination or combination opportunities. These three DFA techniques are integrated within a reverse engineering and redesign methodology. They are then applied to a industrial design application, i.e., redesign of an auxiliary automobile visor. Results demonstrate definitive part count reduction, while maintaining and improving design functionality.

Functional Evaluation Based on Function Content

Function is a key concept to integrate design object modeling and design process modeling in design. We here propose the FEP (Functional Evolution Process) model in order to integrate design object modeling and design process modeling. In the FEP model, the model of a design object is evolved through three steps, i.e., function description, function actualization and function evaluation. Function description is the step in which a designer modifies required functions of a design object. Function actualization depicts a process to obtain physical descriptions from functional description. Function evaluation is a process to measure realizability of functions of the design object. However, among other steps, how to treat the function evaluation is one of the most important theme, because evaluation executed by designers is based on subjective, ambiguous and tacit standards. We discuss a methodology for evaluating function and propose the function content that quantifies functions and enables evaluation of functions. The function content is a similar concept of Shannon’s information content and we show an example of functional optimization based on this scheme.

Design for Variety: A Methodology for Understanding the Costs of Product Proliferation

This paper further develops the previously introduced concept of Design for Variety (DFV). Our study seeks a tool that enables product managers to estimate the cost of introducing variety into their product line. This will help them to maximize market coverage while maintaining required profit margins. Variety incurs many indirect costs that are not always well understood or are difficult to capture. These costs are often not considered by people making the decision about introducing variety. Our DFV model attempts to capture these indirect costs through the measurement of three indices: commonality, differentiation point, and set-up cost. These indices will allow the decision makers to estimate some of the generally unmeasurable costs of providing variety. We conclude this paper by discussing our validation plans for testing the model in industry.