The Affordance of Absence

We originally studied affordances to design products that encourage resource-efficient behavior in users. This paper was motivated by the observation that a lack of resources affected the ability of impoverished slum residents to perceive affordances. Data gathered from a trip to Bangladesh support recent postulations that affordance perception depends on user intention and socio-cultural norms, which are also influenced by fixation and training. We thus became interested in how absence, whether of material, components, or entire products, affected the utility of objects. We describe three dimensions of absence, one major and two minor. The major dimension is used to express the range of physical absence, i.e., of material in a part, of a part in a product, and of the entire product. Minor dimensions include the extent of user control and the permanence of absence, each of which can be used to increase utility in objects. We provide existing examples along these dimensions and describe concepts along the major, physical dimension of absence. We propose that the affordance of absence can be used as an approach to identify novel affordances, and conclude by placing it in the context of existing affordance-based design methods.

A Novel Method for Providing Global Assessments of Design Concepts Using Single-Word Adjectives and Semantic Similarity

Engineering design idea-generation sessions often result in dozens, if not hundreds, of ideas. These ideas must be quickly evaluated and filtered in order to select a few candidate concepts to move forward in the design process. While creativity is often stressed in the conceptual phases of design, it receives little attention in these later phases — particularly during concept selection. This is largely because there are no methods for quickly rating or identifying worthwhile creative concepts during this process. Therefore, the purpose of this study was to develop and test a novel method for evaluating the creativity and feasibility of design concepts and compare this method to gold standards in our field. The SCAT method employed in this paper uses word selections and semantic similarity to quickly and effectively evaluate candidate concepts for their creativity and feasibility. This method requires little knowledge of the rating process by the evaluator. We tested this method with 10 engineering designers and three different design tasks. Our results revealed that SCAT ratings can be used as a proxy for measuring design concepts but there are modifications that could enhance its utility. This work contributes to our understanding of how to evaluate creativity after idea generation and provides a framework for further research in this field.

Analogy Seeded Mind-Maps: Testing of a New Design-by-Analogy Tool

Recent research has investigated methods based on design-by-analogy meant to enhance concept generation. This paper presents Analogy Seeded Mind-Maps, a new method to prompt generation of analogous solution principles drawn from multiple analogical domains. The method was evaluated in two separate design studies using senior engineering students. The method begins with identifying a primary functional design requirement such as “eject part.” We used this functional requirement “seed” to generate a WordTree of grammatically analogical words for each design team. We randomly selected a set of words from each WordTree list with varying lexical “distances” from the seed word, and used them to populate the first-level nodes of a mind-map, with the functional requirement seed as the central hub. Design team members first used the word list to individually generate solutions and then performed team concept generation using the analogically seeded mind-map. Quantity and uniqueness of the resulting verbal solution principles were evaluated. The solution principles were further analyzed to determine if the lexical “distance” from the seed word had an effect on the evaluated design metrics. The results of this study show Analogy Seeded Mind-Maps to be useful tool in generating analogous solutions for engineering design problems.

Validity and Predictive Ability of Wilde’s Cognitive Teamology Model to Design Team Outcomes

An extensive analysis of the validity of Wilde’s Teamology cognitive diversity model was undertaken with 120 teams composed of over 661 participants. Myers-Briggs Type Indicator (MBTI) data was collected using a qualified test over five years from students enrolled in a fourth year capstone design course. Cognitive factor scores using Wilde’s Teamology model were calculated from the MBTI data for eight factors associated with Wilde’s Information Collection and Decision Making dimensions. Wilde’s team formation model was found to nominally contribute 10.2% to the overall prediction of the variance observed in design team outcomes using a linear regression model with a threshold that the cognitive scores must exceed. Wilde’s Teamology factors of Imagination (“prophetic, guided by inner fantasies and visions”), Community (“expressive, tactful builder of group moral”), and Evaluation (“uses personal values to distinguish good/bad”) were found to be statistically associated to design team outcomes.

Leveraging Mechanical 3D CAD Systems Through Improved Model Quality Based on Best Practices and Rubrics

CAD data quality may be leveraged by quality-oriented CAD instructional strategies, but current mechanical CAD practice fails in enforcing quality. The concept of CAD model quality is reviewed to discover how to convey different dimensions of quality through rubrics. The paper describes lessons learned from pilot studies designed to gain knowledge on introducing best practices throughout the training period of novice product designers. Best practices are conveyed by rubrics, so leading to increased quality in CAD models. Rubrics must adapt to the specific concept practiced at each stage of the training period. In this way, they become helpful in disclosing which currently available strategies and tools to enforce quality may be early comprehended and how they are better introduced. Lessons learned from pilot studies are proposed to be reformulated as strong hypothesis that should be validated or rejected in the future, by way of experiments with suitable statistical power.

A Biologically Inspired Design Approach for Low Cost Solar Panel Systems

Biologically inspired design is the process of using biological systems as analogues to develop innovative solutions for engineering problems. This paper describes an effective and successful implementation of problem-driven biologically inspired design in a real-world problem. In support of the Department of Energy SunShot Initiative, a national collaborative effort to make solar energy cost-competitive with other forms of electricity by the end of the decade, solar panel designs were carried out by engineering and architectural design teams. Solar Photovoltaic (PV) systems were developed using analogical design, and more specifically, bio-inspired design. Some systems were also designed using non-biological analogues. Functional decompositions were employed as the first step in the design process, as a way to identify the key functions essential to the system’s reliability and cost effectiveness. Six key functions were identified. Analysis of the final designs by the teams showed that the solar panel system designs using biologically inspired analogues were more effective in meeting the six key functions identified during functional decomposition. Employing a combination of divergent and convergent design thinking is also discussed as a way for effective biologically inspired design. The top three designs selected for prototyping were biologically inspired and exceeded the project goal of reducing the installation and labor costs of solar PV systems by 50%.

Set-Based Thinking in the Engineering Design Community and Beyond

Since a series of academic case studies had revealed Toyota’s unique product development practices to the world, a flurry of research has been conducted into set-based design, also known as set-based concurrent engineering. In this paper, we review work related to set-based design across academic communities in efforts to find common themes and influences. After a review of this literature, we inductively arrive at two Principles of Set-Based Thinking: considering sets of distinct alternatives concurrently and delaying convergent decision making. These Principles allow us to articulate a working description of set-based design. We then examine these two Principles at work in a case example of a common theoretical construct in design.

Biased Information Passing Between Subsystems Over Time in Complex System Design

The early stage design of large-scale engineering systems challenges design teams to balance a complex set of considerations. Established structured approaches for optimizing complex system designs offer strategies for achieving optimal solutions, but in practice sub-optimal system-level results are often reached due to factors such as satisficing, ill-defined problems or other project constraints. Twelve sub-system and system-level practitioners at a large aerospace organization were interviewed to understand the ways in which they integrate sub-systems. Responses showed sub-system team members often presented conservative, worst-case scenarios to other sub-systems when negotiating a trade-off as a way of hedging their own future needs. This practice of biased information passing, referred to informally by the practitioners as adding “margins,” is modeled with a series of optimization simulations. Three “bias” conditions were tested: no bias, a constant bias and a bias which decreases with time. Results from the simulations show that biased information passing negatively affects both the number of iterations needed to reach and the Pareto optimality of system-level solutions. Results are also compared to the interview responses and highlight several themes with respect to complex system design practice.

Quantitative Comparison of High- and Low-Performing Teams in a Design Task Subject to Drastic Changes

Many design tasks are subject to changes in goals or constraints. For instance, a client might modify specifications after design has commenced, or a competitor may introduce a new technology or feature. A design team often cannot anticipate such changes, yet they pose a considerable challenge. This paper presents a study where engineering teams sought to solve a design task that was subject to two large, unexpected changes in problem formulation that occurred during problem solving. Continuous design data was collected to observe how the designers responded to the changes. We show that high- and low-performing teams demonstrated very different approaches to solving the problem and overcoming the changes. In particular, high-performing teams achieved simple designs and extensively explored small portions of the design space; low-performing teams explored complex designs with little exploration around a target area of the design space. These strategic differences are interpreted with respect to cognitive load theory and goal theory. The results raise questions as to the relationship between characteristics of design problems and solution strategies. In addition, an attempt at increasing the teams’ resilience in the face of unexpected changes is introduced by encouraging early divergent search.

Research on the Wet Clutch Engagement Torque

The driving performance of the vehicle with automatic transmission is influenced by the performance of the wet clutch directly. But at present it is still a challenge to build a reliable predictable model for the torque of the engagement process of the wet clutch. Focusing on the wet clutch of vehicle, this paper starts from mechanism analysis, and a modified Reynolds equation with the consideration of the centrifugal force of the squeeze-film is established. In the model, we can consider the speeds of the friction and separator plates independently. At the same time, flow factors have been used to research the impacts of rough surface on the flow of the lubrication oil. In the three-dimensional solution domain, the circumferential pressure gradient of lubrication oil is considered. The model is solved with the finite volume method. The simulation of the torque of the asperity contact calculates the real contact area changed with the engagement process, and the microscopic texture direction of rough surface is considered. Subsequently, the squeeze-film flow model is combined with the asperity contact model to create an integrated clutch engagement model. Finally, the influence of applied force, viscosity of lubrication oil, friction material, the depth of grooves and the width of the grooves are investigated. Based on the comparison with the experimental data, the performance of the proposed model is found satisfactory. Because in this model more detail properties of material and geometric features of the friction plate are include, the wet clutch model developed in this research can become a baseline model for the prediction of the engagement behavior of a real wet clutch. The present model may become an efficient alternative to laboratory testing and lead to designs that can not be envisioned by other approaches.