Computer tools for embodiment and detailed engineering design (computer-aided design (CAD)) evolved rapidly in the past 35 years and are now pervasive throughout the industry. But todays commercial CAD is geometry-centric, not appropriate for early stages of design when detailed geometry and dimensions are not known. This paper describes a framework and a set of interconnected tools for conceptual design. In this system, a broad range of intuitive and experiential concept generation methods have been operationalized and implemented as databases, artifact repositories, knowledge bases, and interactive procedures to promote divergent thinking. The so-called “Design Ideator” includes methods for flexible and dynamic design problem formulation, re-formulation, and restructuring in the form of hierarchical and re-configurable morphological charts. This tool has been continuously enhanced through three phases of user studies and feedback. The main contributions of this work are as follows. First, this research has created a holistic framework with interlaced knowledge bases from a wide range of methods, as opposed to past research that have relied on single experiential only method. Second, we have formulated algorithms to support several intuitive methods, such as contextual shifting, analogical reasoning, provocative stimuli, and combinatorial play.

A challenge systems engineers and designers face when applying system failure risk assessment methods such as probabilistic risk assessment (PRA) during conceptual design is their reliance on historical data and behavioral models. This paper presents a framework for exploring a space of functional models using graph rewriting rules and a qualitative failure simulation framework that presents information in an intuitive manner for human-in-the-loop decision-making and human-guided design. An example is presented wherein a functional model of an electrical power system testbed is iteratively perturbed to generate alternatives. The alternative functional models suggest different approaches to mitigating an emergent system failure vulnerability in the electrical power system's heat extraction capability. A preferred functional model configuration that has a desirable failure flow distribution can then be identified. The method presented here helps systems designers to better understand where failures propagate through systems and guides modification of systems functional models to adjust the way in which systems fail to have more desirable characteristics.

Conceptual design is an early stage in the product design process, which has an essential effect on product innovation. This paper is devoted to computational conceptual design utilizing design synthesis. After the functional model was proposed, the physical parameter model was put forward. The integrated model of function repository and solution repository based on space matrix was built up. The computational conceptual design process based on space matrix was then proposed, including design synthesis algorithm based on space matrix, feature matching based on physical parameter, solutions constraints matching based on design catalog, functional structure design based on functional structure evolutionary model, and evaluation and selection approach based on design catalog. The conceptual design of new devices for decreasing resistance of amphibious vehicles is given as an example, which demonstrates that the methodology is helpful to produce valuable solutions for product innovation.

Conceptual design is a high-level cognitive activity that draws upon distinctive human mental abilities. An early and fundamental part of the design process is problem formulation, in which designers determine the structure of the problem space they will later search. Although many tools have been developed to aid the later stages of design, few tools exist that aid designers in the early stages. In this paper, we describe Problem Formulator, an interactive environment that focuses on this stage of the design process. This tool has representations and operations that let designers create, visualize, explore, and reflect on their formulations. Although this process remains entirely under the user's control, these capabilities make the system well positioned to aid the early stages of conceptual design.

In this study, we attempted to develop a method that applies the notion and technology of natural language processing for operating a function dividing process in conceptual design. We formulated a function dividing process from a linguistic viewpoint and constructed linguistic hierarchal structures in this process. This method is significant in identifying hierarchal relationships between the upper- and lower-level functions from the viewpoint of linguistic hierarchal relations. An experiment was carried out to confirm whether the proposed methods were feasible and whether the extracted relations were meaningful for supporting the function dividing process.

Integrated Systems Health Management (ISHM) is an evolving technology used to detect, assess, and isolate faults in complex systems to improve safety. At the conceptual design level, system-level engineers must make decisions regarding the inclusion of ISHM and the extent and type of the sensing technologies used in various subsystems. In this paper, we propose an ISHM design tool to be used in conjunction with standard system modeling methods to help with the integration of ISHM into the system design process. The key to this analysis is the formulation of an objective function that explicitly quantifies the value derived by integrating the ISHM technology in various subsystems. Ultimately, to determine the best ISHM system configuration, an objective function is formulated, referred to as profit, which is expressed as the product of system availability ( A S ) and revenue per unit availability ( R ) , minus the sum of cost of detection ( C D ) and cost of risk ( C R ) . The analysis is conducted at the system functional level appropriate for conceptual design using standard system functional modeling methods, and ISHM is allocated to the functional blocks using the ISHM design tool. The proposed method is demonstrated using a simplified aerospace system design problem resulting in a configuration of sensors, which optimizes the value of the ISHM system for the given input parameters. In this problem, profit was increased by 11%, inspection interval increased by a factor of 1.5 and cost of risk reduced by a factor of 2.4 over a system with no ISHM.

In this paper, we present our findings on the development of a taxonomy for electromechanical components. In building this taxonomy, we have two main objectives: First, we strive to establish a framework for future computational tools that archive, search, or reuse component knowledge during the conceptual phase of design. Second, we aim to define a standard vocabulary that derives uniformity and consistency in the representation of electromechanical component space. Through both empirically dissecting existing products and defining categories based on functional analysis, we defined 135 generic component types. The use and necessity of the resulting taxonomy by a suite of computational design tools are illustrated in two applications of conceptual design.

A well-constrained geometric system seldom occurs in practice, especially at the sketch-based initial conceptual design stage. Usually, it is either under- or overconstrained because design is a progressive process and it is difficult for a designer to specify all involved constraints in a consistent way. This paper presents a priority-based graph-reduction solution, in which each constraint is assigned with a priority to guide the reduction of a geometric constraint graph. The advantage of this method lies in its ability to find the optimal solutions to a geometric constraint system automatically, without requiring interactive intervention from users.

Features allow one to associate human knowledge and product geometry. The authors proposed, in earlier publications, a unified feature modeling scheme with the aim to maintain the integrity and consistency of a product model. Different application feature models within and across different product life-cycle stages are integrated, and especially, nongeometric relations (besides geometric ones) are handled. In this paper, as an improvement to the previous work, two types of associations are introduced: sharing and dependency. In the context of conceptual and detail design stages, these associations are described and the implementation is discussed in detail.

During conceptual design of systems, the emphasis is on generating the system architecture: the configuration of sub-systems and the interactions between them. Ports, as locations of intended interaction, play an important role at this stage of design. They are convenient abstractions for representing the intended exchange of signals, energy or material; they can be applied at different levels of detail, across different energy domains, and to all aspects of design: form, function, and behavior. But to play this versatile role, ports need to be represented in an unambiguous yet flexible fashion, accommodating the differences in vocabulary and approach across different disciplines and perspectives. In this article, we introduce the semantic structure for such an unambiguous representation: a port ontology. The ontology formalizes the conceptualization of ports such that engineers and computer aided design applications can reason about component connections and interactions in system configuration. It defines ports in terms of form, function and behavior attributes and further includes axioms that can be used to support a variety of engineering design tasks, such as port refinement, port compatibility checking, and the instantiation of interaction models. A LEGO example is used to illustrate the ontology and its applications in conceptual design.

To be able to model industrial products in conceptual design, aspects such as function, structure, shape, behavior, sustainability and service are typically considered. Tools developed until now usually focus on individual aspects. The author proposes a new modeling approach called vague discrete interval modeling (VDIM) that integrates shape, structure and behavior modeling. The integration is achieved by the introduction of a multipurpose modeling entity called particle. VDIM offers three means for the representation of a cluster of shapes, for instances of shapes and for physically-based manipulation of shapes. Interval modeling allows representing uncertainty of shapes, which is a characteristic property in shape conceptualization. In addition, particle systems can be applied to model the mechanical behavior of the product. This constructive modeling approach makes it possible to describe the procedural model of incomplete geometries and to capture the structural relations between components. The paper reports on the computational issues related to VDIM.

This is the second and final publication analyzing presence, immersive tendencies of individuals, and design comprehension. The effectiveness measurement problem is described in this article by means of a methodology to find the best design review process subject to certain criteria. The effectiveness measurement problem originates from our inability to logically understand the impact of a process or media differences on design comprehension; and it reconciles such differences in strengths of media that cannot be effectively covered by the relationship problem described in the first technical note. We illustrate the methodology with design review experiments where Computer Aided Virtual Environment (CAVE™ 2 ) is investigated as a possible virtual environment for product design reviews. Based on the measurable usability attributes of the design review process, the CAVE was considered to be a good solution achieving maximum utility. However, costs may hinder the ability to use CAVE as a tool.

The conceptual design review process is a critical cost determining step for complex products such as ground vehicles. The use of virtual environments (VEs) in this process has become increasingly popular with the advancement of 3D visualization technologies. Important to feelings experienced by participants in a VE are two parameters: presence and immersion. Presence is defined as the subjective experience of being in one place while physically being situated in another. Immersion is a state characterized by perceiving oneself to be enveloped by, included in, and interacting in an environment that provides a continuous stream of stimuli. While different virtual reality (VR) devices provide different degrees of presence and immersion, the amount of each is also dependent on the individual. In this paper, a relationship among presence, immersive tendencies of individuals, and design comprehension are explored. Further, a methodology to find the best design review process subject to certain criteria is presented. The results of two experiments involving the CAVE Automatic Virtual Environment CAVE ™ 2 are discussed and evaluated. In one case, the U.S. Army investigates the use of the CAVE as a conceptual design review environment for advanced military vehicles in a comparison test with its present method of concept presentation and review. In a second experiment, CAVE users responded to a survey to determine the potential of VEs to improve design comprehension and immersive tendencies. In both cases, positive presence and immersion results support the idea that VEs offer advantages for conceptual design reviews over more traditional methods.