Testing prototypes with intended end users is critical to the design process. There is limited research on testing prototypes with certain types of end users, specifically children for toy products. Additionally, prototypes evolve in fidelity throughout a project, adding to the complexity in developing best practices for prototype testing. This paper analyzes children's understanding of physical prototypes at various levels of fidelity throughout a university semester-long design project developing wooden toys. Through analyzing students’ feedback on their prototype testing sessions, aspects of the prototypes that aid or inhibit children from understanding both form and function are uncovered. These aspects relate to Norman's principles of interaction and their inclusion in prototypes, specifically mental models, signifiers, and affordances. This paper suggests to include these principles in prototypes early in development to guide the user during testing. The goal of this research is to be a resource for those developing products for children, as well as adding knowledge around prototyping testing at various levels of fidelity.

Topology Optimization (TO) is an established method for the development of high strength and lightweight structural components. However, its results have to be geometrically revised to obtain a computational model that meets product development requirements. Design has to be in accordance with manufacturing constraints. Geometry reconstruction therefore still is a typically manual and tedious task, but increasingly supported by computational and automated approaches. In this paper, the inclusion of a casting constraint in an automated Medial Axis based reconstruction method is presented. Since the Medial Axis provides cross-section values by the computation of maximally inscribed spheres, this information is used for geometry reconstruction and even further for the purposeful adaption of the cross-section to match Heuver's circle method. Thereby, the directed solidification of molten material is considered. With a predefined feeder position, the demonstrator of a suspension control arm is used to show the application of the method. Resulting CAD-models are also structurally evaluated for their stiffness characteristics.

3D printing is a widely used technology for automating the fabrication of prototypes. The benefits are wide reaching, and include low required expertise, accurate geometric form and the processibility of many materials. However, production of certain forms – especially large forms – can be slow. From review of the sub-systems, the hotend is commonly found to be the limiting factor. To improve this, a modified nozzle design is considered that incorporates a flat copper plate within the flow stream. Analytical simulation was used to guide this design before experimental methods validated the modifications. The maximum volumetric rate for the standard hotend nozzle is 14 mm3/s. The best performing modified nozzle increased the maximum volumetric flow rate to 26 mm3/s – an 86% increase. A series of popular parts were further considered, demonstrating a maximum ∼48% fabrication time reduction, and a mean of ∼23%. This enables 3D printed prototypes to be made more efficiently – both with regards to the design cycle and energy use – and allows designers to use the technology more rapidly than previously possible. By extension, this improves the efficiency of the design process.

One life-cycle issue that is often overlooked in the design process is that of intellectual property (IP). Yet the IP associated with a product is a valuable asset of the company, sometime comparable to the materials produced or the manufacturing infrastructure. In particular, this paper addresses the IP of patents, the opportunity for patent infringement, and ways to reduce the risk of getting into this situation. One poorly managed patent infringement case could cost the company millions of dollars, wiping out years of profit from production of that product. Patent infringement is a complex topic that combines design and law with many uncertainties. Designing products that do not infringe the patent rights of others is a goal that cannot be done with certainty. A primary reason is due to the uncertainty of understanding what is protected in a patent and the uncertainty of the patent infringement process. The purpose of this paper is to educate the designer on what constitutes patent infringement and explain some ways to reduce the risk of infringing the patent rights of others.

Contemporary digital in ear hearing aids are of significant importance for social participation of users with hearing impairments. Through the advancement of technology, extreme miniaturisation of these devices has been achieved. However, by no means all people who could benefit from a hearing aid actually use one. Cormack and Fortnum state that the majority (80%) of adults aged 55–74 years who would benefit from a hearing aid, do not use them. This is in line with Arnold and Makenzie who estimate a gap of a factor of 5 between people who would benefit from the use of a hearing aid than actually do acquire and use one. Even according to the statistics from the Federal Guild of Hearing Aid Acousticians in Germany, only 3.7 million use a hearing aid out of 5.4 million who have an induced hearing loss. This article explores the design space of fashionable analogue contemporary hearing aids.

The study aims to identify the relations between creative design quality and content of the memorising precedents, association, and combination of information processes in a design context. 71 participants were recruited to finish a creative design task. Think aloud and interview were conducted during and after the creative design task to understand the content of the memorising precedents, association, and combination of information processes. The 71 creative designs were then assessed by five experts in creative design. The results from this study revealed that participants who generated high-creativity design tend to memorize various topic-related precedents, associate items based on topic-related information, and combine topic-related information with products. Participants who generated low-creativity design tend to memorize characteristics of a specific space of the design topic, associate items based on specific topic-related information, and add the topic-related pattern to a product.

The use of sensor networks (SNs) on the surface or the inside of large-scale components allows the continuous acquisition of data on the applied loads and their structural integrity. A lot of publications on SN's system reliability deal with this topic from a hardware- or a data- and energy-oriented viewpoint. To give an overview on the state of the art in the field of reliability-oriented concept-optimization of SNs, a Systematic Literature Review is conducted. The found literature is used to investigate how different models combine the different viewpoints to analyse the system reliability. By analysing the results regarding the used reliability indicators and methods to assess the system reliability from the different viewpoints, it can be observed that most publications deal with the accuracy, loss and delay of data as well as the energy consumption in SNs. Few publications use common modelling methods like reliability block diagrams or Markov chains with a focus on the hardware reliability. Furthermore, none of the found publications combines the data, hardware and energy perspective and uses them to optimize a SN regarding its reliability from all three viewpoints.

Engineering departments design infrastructure by applying rule systems. The latter are an old creation heritage, based on decades of engineering, that makes it possible to design and govern the operation of the physical heritage which is the infrastructure. Replacing the infrastructure is not sustainable in the meaning of grand challenges; renovating it by applying engineering rules is but could appear too expensive. The literature highlights situations where renovation by respecting the state of the art is too costly and so is the validation of new renovation rules. Are there forms of frugal validation that allow for sustainable renovation of existing systems? This paper tries to explore a third way, a renovation of the physical heritage from a renovation of the system of rules, conceiving in the system of rules, new propositions, and their validation. Using the C-K theory, a case analysis was performed within the French national rail network manager (SNCF Network), a company that has a historical engineering heritage and is at the same time implementing a renovation of it. The paper shows that the renovation of engineering departments’ creation heritage can go through frugal validation patterns and constructive proof logics.

Nowadays, companies operate in increasingly competitive and dynamic markets with fast-changing customer needs. Simultaneously, major advances are being made in information and communication technologies, and the digitization of products is progressing. Based on these economic and technological trends, smart product-service systems (PSS) are emerging as a new form of business model. Recent studies show that the transition to developing smart PSS is a major challenge for companies and that they require methodological support, as their internal structures are undergoing significant changes.

In order to provide a sound basis for support, we have undertaken a comprehensive study to identify requirements for a smart PSS development framework. 24 interviews and 5 workshops with companies that have recently focused on the development of smart PSS provide a rich set of empirical data to explore the challenges faced by companies today. We systematically analyzed the data and evaluated the results with our respondents. To increase the robustness and generalizability of our findings, we performed a contextual literature review and analyzed additional cases. This led us to a set of 17 requirements for a smart PSS development framework.

Design representations are important tools for designers in the design process. To help designers choose the appropriate representation, taxonomies have been proposed based on type, degree of fidelity, and when to use them. However, Design representations may also play an important role in designers' communication with users and enabling users as co-designers. Therefore, new taxonomies, focusing on design representations’ potential mediating roles in collaborative design processes with users, have been developed. The purpose of this interview study, with twelve designers within Swedish industry, was thus to investigate how designers use design representations in communication with users in the design process. The study indicates that the designers mainly interacted with users in order for them to answer specific design questions or to evaluate design solutions. If design representations’ value for facilitating communication and collaboration with users should be emphasized, we need to shift from teaching mainly taxonomies related to fidelity levels or when to use them in the design process, and rather educate future designers about design representations inherent potential to mediate and enhance the dialogue with users.

User Experience is becoming an increasing centre of interest both in the academic and industrial worlds. Design agencies are no strangers to this phenomenon and are willing to shift from product-oriented design toward user experience design. However, their design process is often loose which may explain a lack of final UX quality or proof of quality, and does not allow to diagnose misuses and improvement opportunities due to a lack of UX formulation and traceability. We propose in this paper to retrospectively represent a design project and its specified, designed and validated UX, in the perspective to conduct a posterior collective diagnosis of UX design in a design agency. The proposed representation model is used to analyse one design project. Results show that only a few UX traces are found in the presented project, and that many dimensions are not considered (like perceptions or affects). Finally, we discuss the next steps of this tool's deployment to create a shared mental model of the design process among the design players.

In today's VUCA-World it is necessary to consider future requirements to develop change- and future-robust future products, especially regarding the increasing demand for sustainable solutions. In order to address this situation, upgradeability of modular products can be a solution. Considering that elements of modular products are used in several different products and over a long period of time, there is a need to act on this challenge. To uncover areas with a need for action, a systematic literature review on upgradeable and modular products was conducted. After resolving four fields of action and under consideration of the need for sustainable products, another systematic literature review examined the solution space of upgradable modular product architecture. In conclusion, several influencing factors on the upgradeable design of modular products could be identified, which are presented in this work.

Lifetime prognoses are fundamentally important to improve products regarding safety, costs, availability and sustainability. To modelling the lifetime of a system or its components and subsystems different methods and model approaches are available, which are not compatible in any case. Depending on the system, use case and available data, the existing model approaches and modelling methods are differently suitable for a precise lifetime prediction. In this contribution a procedure was developed to help in the selection of suitable approach-method combinations. For this purpose, the compatibility of method types with the different model approaches was assessed and criteria for the pre-selection of suitable approaches and methods for lifetime modelling were defined. The selection procedure was applied to the example of entities for electric powertrains of aircraft in early design stages. Finally, the results were summarized and evaluated. The insights gained in this paper can help to enhance lifetime models of products in early design phases.

In Additive Manufacturing (AM), new generations of polymer composites presented as engineering- grade materials provide high-end mechanical properties with the design freedom AM provides. Interlayer anisotropy is the main challenge in both in-situ optimization and post-analysis in transitioning from prototypes to high-performance components in fused filament fabrication (FFF). Recent studies show a direct correlation between layer fusion temperature and mechanical properties. In this paper, we present synchronized position and temperature data and study how a component changes based on layer height and geometry. An IR sensor transfers data while printing a G-code generated by FullControllGcode, printing in a single direction and recording temperature in front of the nozzle. Results show that within each layer, a Δt of 20°C at thinner geometries, the heat loss will provide a reduction in mechanical properties and further heat loss occurs when moving away from the heated bed. By using the presented temperature mesh in further studies, post- printed anisotropic components can be analyzed by FEM, and the FFF process can be adaptively optimized based on location, size and geometry.

Service design has been an emerging transdisciplinary field that includes product, system, and social science, since the term was first introduced to academic research in the early 1990s. With socioeconomical shifts and emerging technologies, people have faced more complex and systemic challenges, which enable researchers to consider how to reapply service design not only as problem-solving tools but also as ways for communication and alignment to adapt to the change. The study focuses on the paradigm shifts of service from its definitions to applications by interviewing nine design experts from academia and industry, and utilizing survey results to help us explore applying service design to solve complicated social-technological challenges. We present four takeaways: 1) a new understanding of service design, 2) the purpose of using service design tools, 3) the evaluation of service quality through time, and 4) the applications of service design in the public sector. We proposed a macro-trend model with service systems: product, service, and experience to conclude 1) constructing service systems in the macro-trend context and 2) gaining holistic views and building service implementation capability in the era of transformations.

Design aesthetics are one of the most important factors affecting the attractiveness of industrial products. Psychological theory suggests that a moderate level of novelty and complexity yields pleasant feelings in users. A design that is initially surprising to consumers and acceptable over time requires aesthetic interest associated with its novelty and complexity. In this study, we formulated the perceived novelty and complexity of a closed contour shape. Based on this formulation, we developed “Hybrid-GAN,” which is a shape-generation system capable of generating a variety of shapes of arbitrary novelty and complexity. In a series of experiment, we obtained subjective evaluations of novelty and complexity, as well as beauty and interest, for the generated shape samples. The results indicated that our novelty and complexity formulations had significant positive correlations with subjective evaluations. The sum of the formulated novelty and complexity also had a significant positive correlation with interest. The results of this study are expected to be used to support the design of attractive shapes by providing feedback to designers regarding the degrees of novelty and complexity that users find most pleasant.

In times of ‘grand challenges’, design theorists dealing with complex systems are facing a dilemma: grand challenges require rule breaking, but they also require the preservation, as much as possible, of existing resources, systems, know-how and societal values. Design for transition calls not for ‘creative destruction’, but for ‘creative preservation’. How do we model a design process that involves ‘creative preservation’?

Today, it is recognized that category/topos theory provides a solid foundation for modelling complex systems and their evolution in design processes. Category theory can account for a design process inside a given ‘theory of the object’, while topos theory and design theory can account for the phenomena whereby a design process is innovative to preserve the knowledge structure. At the heart of this creative preservation is sheafification.

In this study, we analyse the sheafification process using design theory. First, we characterize sheafification from a design perspective. Next, we propose a very simple illustration involving the sheafification of an ordinal 2 category presheaf. Finally, we show how sheafification can be used to enable ‘creative preservation’ in specific complex systems.

Additive manufacture (AM) enables a greatly increased design freedom owing to its ability to manufacture otherwise difficult or impossible geometries. However, design creativity can often present itself as a barrier to realising the advantages that AM could offer. In this study the use of AM, bioresorbable materials and lattice design is considered as a method of satisfying contradicting design requirements during fracture healing. Often, immediately after a fracture high stiffness fixation is required; contradictingly during the remodelling phase high stiffness can inhibit bone healing. This study proposes the use of a bioresorbable body centred cubic (BCC) or face centred cubic (FCC) lattice structure to meet the need for tailored variation in implant stiffness over time. To reduce computational expense of lattice modelling a method is outlined, including the use of homogenisation. Results show homogenised representations perform within 5.2% and 1.4% for BCC and FCC unit cells respectively, with a 95% reduction in computational expense. Using resorption rates from the literature, time-dependent change in unit cell geometry was also modelled, showing the way in which a decrease in stiffness over time could be achieved.

Social augmentation refers to a human-computer integration technology that aims to enhance the user's social skills by supporting empathy, interaction and communication. This study investigated the implementation of social augmentation in hearing protection within the context of entertainment. Through a user-centred analysis, potential social augmentation functions for earplugs were conceived. Three innovative conceptual prototypes were then developed, each enriched with three social functions. Accordingly, each of these concepts should ensure that social skill is enhanced, facilitated or improved. To assess whether the concepts were successful, the social impact of the prototypes on the user and bystanders was evaluated and compared through questionnaires and focus groups using video footage. The results provided promising conclusions regarding the applied methodology and the potential for optimizing the iteration process of innovative human augmentation concepts.

Engineering design research has largely focused on normative models of decision analysis based on small world causal frames where uncertainty can be resolved as probabilities or probability distributions. However, today we need to design solutions for our built environment that are sustainable, just, and able to adapt. Because of the scale and complexity of our world, designs that address sustainability, justice, and adaptability are dominated by unresolvable uncertainty. This requires large world frames and new engineering design frameworks and tools that provide a much broader and nuanced understanding of the impact of our engineering decisions. In this paper we propose that these tools will need to link quantitative and qualitative data and engineering judgment using narrative decision-making processes. To support this, we provide two examples where engineering decision-making is based in part on narrative processes. We then identify five research areas that require additional research to support large-world frames including (1) how can we create microcosms that enable transition between large- and small-world frames and (2) how engineers develop conviction to act using the narratives they create.