Abstract: Product design is an activity that must be supported by information in order to allow designers to conceive solutions to real problems that do not introduce further issues, first of all, environmental concerns. Axiomatic design is an approach that provides the possibility to check whether a design solution is functionally valid and it can also be extended considering eco-design elements. In a synthetic representation of 1D and 2D arrays, it can inform designers about the level of sustainability of the product on which they have been working on since the first phase of design when they start to embody functionalities by introducing real components, and first assemblies appear. To achieve this task, the domains considered in the original formulation of Axiomatic Design have been revised, and a new domain has been introduced. This allows designers to take into account all the phases of product life and improve design solutions to avoid introducing structures, components, and functionalities that might be the cause of environmental problems. The paper describes such new mapping among domains and applies it to design a daily life device. The contents of the new data structure will be presented and discussed.

Keywords: Axiomatic design | Design matrix | Mapping among domains | Sustainability matrix | Sustainable products design

Abstract: ASME Y14.5 and Y14.43 standards share the task to define a coherent context in which geometric tolerances may find a rational approach. Even ASME Y14.5 defines the rules, meanings, and descriptions of geometric tolerances, ASME Y14.43 applies them aiming to design and build functional gages able to check if the geometric characteristics, assigned on a drawing, have been reached in a physical component. Many of the assumptions given in the ASME Y14.5 may be understood only when the design of a functional gage is approached. The need to build such kind of device is strictly connected with the need of industry that requires best-practices able to check geometric characteristics of products in a short time. The basic elements of ASME Y14.43 are summarized in the paper and a functional gage, taken from the edition of 2011, is elaborated and discussed. The root of the American standards has been associated with the philosophical school of pragmatism in which more attention is paid to practical examples and how every theoretical conceivement must be verified by scientific experimentation.

Keywords: Functional gages | Geometric dimensioning and tolerancing | Pragmatism

Abstract: Analyzing an assembly and recognizing how the components can mate with each other in order to satisfy the functionality for which they have been designed is not a trivial task. Teaching such a problem to engineering students requires they are familiar with a set of components and how much larger or thin can be the errors intrinsically related to the technologies employed in their production. A set of steps are necessary to reasoning about the right identification of a chain of dimensions that influences a functionality. Then can be useful to have a table where collect the data, especially when the number of parts is relevant. The paper presents a new format for the table that can be used in all kinds of problems that may occur in design: analysis, analysis with constraints, and synthesis. The way how to employ such a table and the steps to solve each problem is discussed with known examples.

Keywords: Modeling | Tolerance analysis and synthesis | Tolerance stack-up

Abstract: Considering reviewers' opinions on the paper, presented at EPDE2021, in which the data were not sufficient to compare different cohorts, now we are able to answer if there have been differences in students' assessments, based on some questions of the academic survey on didactics, comparing answers for courses held pre-and-during Covid19 pandemic. In 2020 every educational institution moved their didactics toward an online platform. Every course had to introduce and experiment with new forms of didactics that prevent in-person events, either in lectures or laboratory. Courses of design traditionally require a strict relation between student-instructor and student-student. The need to operate by moving the contact to an online connection creates, at the beginning of the period, a lot of distrust among teachers of such courses. The “Machine Drawing” course is one of these. Briefly recalling how the courses have been revised, with the employment of a communication platform like Teams®, the answers, given by students, are collected and the differences along the time are highlighted. Three academic years have been considered: 2017-2018, 2019-2020, and 2020-2021. A further correlation has been made considering different didactics and the global efficiency of the course in terms of abandonment, number of successes (number of people that pass the exam), and the effects on the grades (marks) obtained. Reflecting on such data, a new consideration has been done on the methodologies that can still continue to be used in the future when the explicit problem of pandemic emergency does will not influence anymore the traditional way of teaching.

Keywords: Online didactics | students' assessments | teaching quality improvement

Abstract: Sketching is becoming an irrelevant activity of engineering studies. The availability of many software that aids designers in all phases of design, not only analytic but synthetic, push technicians, designers to use such tools, giving up the employment of a simple pencil and eraser on a sheet of paper. The productivity of software tools is obliged to speed and manage the whole design process; even freehand sketching remains the fundamental means to communicate the first ideas immediately. During Brainwriting sessions, the ability to explain by sketches first elaborations of a possible solution, that must be understood by co-designers, is the first step that allows more fruitful discussion and immediate adjustment towards a quick embodiment of valid proposals. The paper describes how such techniques has been introduced in the mechanical engineering curriculum. The case of study reports the experience of the Brainwriting online, which has been tested during lockdown due to the pandemic disease of COVID-19. Further in the paper it is suggested a new interpretation of the de Saussure general linguistic studies, in term of a communication that is associated to a drawing.

Keywords: Brainwriting | Communicate design intent | Interactive design | Product design | Semiology | Sketching

Abstract: Since Learning Management Systems (LMS) appeared some 20 years ago, their experimentation grew slowly, compared with the explosion that occurred after the Covid-19 emergency. Due to the closure of schools and universities worldwide, every educational institution and their teachers had to move towards the usage of LMSs for Online Distance Learning (ODL). This obliged the teachers to quickly familiarize with such kind of didactics and every kind of course faced these new opportunities. Machine Drawing is a course that requires much interaction between teachers and students and may not exploit validly many modalities invented in LMS. This paper presents the experiences done implementing online didactics, trying to apply all the online tools to the traditional way of teaching. Mainly laboratory activities, made online, must reproduce the interaction made in-person. Nevertheless, online connections opened new ways to try stricter relationships between the teacher and those students, who have less skill, even shyness, and then may accumulate delays. Differentiating the way in which didactics (lecture and laboratory) may be delivered, some traditional techniques have been improved. Employment the video recording of all activities done has given students the opportunity to repeat the more delicate steps of some topics. The check online of designs and elaborations by instructors allows students to be more concentrated on explanation, which may be done collectively or singularly. Comparing the results of exams before and after online didactics revealed that the number of students that passed the exam and the average of reached grade grew significantly.

Keywords: Machine drawing | Online classroom | Virtual class

Abstract: Teaching product design is not a trivisal task. Considering the experience done along 20 years of teaching at master level class in mechanical engineering it is possible to take stock. The model followed is Project-Based Learning and this method can be licensed as the model that gives greater satisfaction to all attendees. Students give high score to the survey organized by university at the end of the course to assess didactic validity. Also, teachers have many stimuli when discussing with students the activities proposed. The course is based on the development of an industrial product that solves a problem, eventually posed by industry or emerged by customers. Based on the course schedule, the different phases of product development put in evidence the steps that require divergent thinking and those where it is necessary to employ convergent thinking. A case study allows explaining all the phases of product design.

Keywords: Integration of design methodologies | Product design and development | Project-Based Learning | Project-Based Pedagogy

Abstract: Mechanical and Management Engineering are some of the stakeholders involved in product development, with different competencies. They must share the responsibility for best solution identification to accordingly answer the customer needs and to authorize the production of products that can have success with a positive economic return. Higher education curricula should prepare such professionals, and this is the reason because courses of product design are proposed to such classes. Even the programmes of the corresponding courses are necessarily different the part related to concept generation is similar. The work aims is to identify analogies and differences between the classes of Mechanical Engineering and Management Engineering, both in the way of leading the generation of concepts and in how the concepts generated have eventually reached the goals of innovation. BrainWriting is a method that can allow students to be productive in concept generation and is based on the two steps of sketching and gallery. This ability must be conjointly employed with the functional study of the problem to be solved. These aspects must be learned by students to avoid fixation, the inconvenience to repeat indefinitely only what is already known. The design alternatives generated by teams of students will be assessed by teachers and experts in the field, following the method proposed by Shah. After such classification, further comparison between the two classes will be done to identify the aspects of the cultural imprinting of such future professionals.

Keywords: BrainWriting | comparison between different classes | creativity and innovation | creativity assessment | Product design education

Abstract: The first phases of designing an industrial product are those in which creativity has the predominant weight in all the design process. Teaching to be creative is extremely complex and ambiguous, given the elusiveness of the mechanisms that guide it. In this work, the process of generating concepts has been observed during the laboratory of a dyad workgroup of master’s degree students in mechanical engineering in a course of Product Design and Development. Starting from a standard session of the 635 method (Brainwriting) it has been observed how the concepts have evolved in a continuous Brainwriting developed in five steps, between feared and almost manifested moments of fixation and exhaustion, towards increasingly mature and conscious solutions, despite the inexperience of the team members. Some aspects have been highlighted on the rotation mechanism of the different Brainwriting sessions and how this has contributed to concepts development; therefore a framework of a three-step Brainwriting session is proposed, which takes inspiration from this experience and those performed of past years.

Keywords: 635 method | Brainwriting | Concept generation | Continuous Brainwriting

Abstract: ANOVA is currently employed in association with the Robust Design in order to discover the parameters most influencing a particular performance of a device in the phase of development. Such relation has been studied for many times and literature is abundant. The peculiar nature of the Taguchi Method with the employment of orthogonal arrays introduces new elements in the investigation of the most influencing parameters. Considering that the plan of the experiment is organized on the base of level parameters combination orthogonal and balanced, ANOVA can be applied to each parameter individually and this gives new insight on the occurrence of noises in correspondence of some levels parameter. The paper analyses this kind of relation, reproducing an example from literature and discussing how ANOVA can be employed in such a study. Robust Design is an extraordinary method to be used in product development with the experiments simulated from CAE analyses. In this context, more conscious employment of such methodologies can aid in managing and organizing the study and experimentation on new products or processes. In another section a second example from the authors is re-proposed and some new insights are shown.

Keywords: ANOVA | Robust Design | Taguchi Method

Abstract: Additive Manufacturing (AM) involves a set of production processes in which a layer-based material deposition approach to build parts is applied. These technologies are now extensively used in the industry in many cases as the main manufacturing process for making components with high shape complexity. The dimensional and geometric accuracy of the parts manufactured by means of AM are mostly determined by the specific type of additive process employed and the related process parameters. The part orientation in the build space is an important process parameter that has an influence on the stair-step effect and on the need of support structures and the subsequent post-processing refinements. In addition, the position of the part in the build volume may have an influence on the shape. These factors concur to the surface finish and to the dimensional and shape accuracy. In this paper, the flatness error on several surfaces, built on a test artefact ad hoc conceived, has been measured by means of a CMM-based setup in order to quantify the variation of the error in relation to: The orientation of the surfaces with respect to the platform, and the position of the part in the build volume of the AM machine. The test part has been produced by Direct Metal Laser Sintering (DMLS) process using the EOS Stainless Steel GP1. The test artifact has been designed with five flat surfaces at different angles with respect to the building platform. Two specimens were built in the same DMLS session with different position and alignment. The influence of the surface slope on the flatness error has been investigated. Flatness, 3D Roughness and orientation errors (parallelism, inclination, perpendicularity) have been measured and compared between both specimens.

Keywords: 3D surface roughness | Additive manufacturing | Flatness | Orientation error

Abstract: The Taguchi method is widely employed in several fields to manage and improve processes. It is interesting that it could be used during product development, considering it as the basic element to quantify the uncertainty of the device performance prediction. During product design, when many design aspects still must be understood by the design team, it is necessary to apply interactive approaches in order to simulate the behaviour of the device, employing CAx tools. Basically it is important to identify the most suitable “loss function” that can be associated with the characteristic function. In order to plane the investigation, the device under development ought to be described in term of the Design Matrix of Axiomatic Design, allowing the designer to characterize the relationship among the functional requirements and the corresponding design parameters. The nature of this relationship, generally not known a priori, can be revealed by the employment of the Taguchi method, once a suitable Objective Function has been chosen and the noise factors are identified. Analysing the performance of a device in a simulation of its behaviour in several operational conditions allows designers to discover whether there are correspondences or contradictions among design parameters. This can be synthetically said a robust design process. In order to enhance these aspects a design of experiment must be planned. The weak point of the procedure consists in the correct choice of the function that characterizes the device behaviour. Considering the wide academic debate on this point, the paper proposes a unique Noise Reduction function to be used in conjunction with all types of “loss function”. The Design Matrix can be checked and its nature can suggest the validity of the product under development and discover contradiction. The paper discusses an interactive procedure able to integrate the Taguchi method and the axiomatic approach.

Keywords: Axiomatic design | Design matrix | Noise reduction | Robust design | Taguchi method

Abstract: Humour may improve performance in creative problem solving as demonstrated in various studies, although the mechanisms underlying this phenomenon are still unclear. In this work the mechanisms of how humour facilitates creative problem solving during the conceptual phase of product design will be investigated. From the educational point of view all the activities that tend to reduce fixation during conceptual design are welcome, because students without specific experiences in work group and in generating original ideas reproduce always what is already known. In order to study the impact of humorous visual stimuli on creativity an experiment was performed. A sample of students of a MSc class in Management Engineering was divided into two sets and engaged to generate ideas concerning benches and shoe racks by Brainwriting (635 method) in two different ways: without stimulus and with stimulus. Three experts evaluated the concepts proposed in the generation phase and the Torrance Test of Creative Thinking (TTCT) was used to measure creativity. A correlation analysis among the different assessments made by evaluators was performed. The interquartile distance method was used to identify and delete the extreme and abnormal values. Finally, a sensitivity analysis was used in order to demonstrate that even changing the TTCT criteria weights the experiment outcome does not vary. The results obtained in this study shows that the concepts obtained using Brainwriting combined with humorous visual stimulation reach better creativity scores than those obtained without stimulation. Lastly, some hypotheses are suggested in order to explain some seemingly contradictory outcomes.

Keywords: Brainwriting | Creative Thinking | Creativity | Humour | Torrance Test of Creative Thinking

Abstract: The article presents a model to support designers and stakeholders when selecting the best product concepts, from among those in the course of development, assessing them from the sustainability point of view. The main aim of the article is to give the designer a road map, by which to collect and organize data, perform environmental analysis and compare different design alternatives, before the embodiment phase is completed. The model integrates different approaches: the use of a simplified life-cycle assessment to assess concepts when the information is poor or rough, performing the evaluation according to a set of environmental indicators; the employment of an augmented version of a design structure matrix, used to manage product components and functionalities; the use of a multi-criteria decision-making method to compare the environmental characteristics of design alternatives and a Pareto approach to select the most promising concepts. Finally, the design alternatives are expressed in terms of three dimensionless coordinates related to material wastes (α), energy dissipation (β) and environmental characteristics (γ) of the concept and are positioned in a three-dimensional environmental efficiency space to allow designers to visualize the position of each concept solution. The employment of an aggregate objective function and its geometric interpretation in the environmental efficiency space allows the designer to have a deeper knowledge of the choices to be made and how these can be taken more consciously. Furthermore, this final step can help designers and stakeholders in their reasoning about the environmental potentialities and drawbacks of the products in the phase of development. The whole model is applied to a case study where a group of five concepts of orange juicers are analysed and all the steps of the model are described in detail and discussed.

Keywords: design structure matrix | environmental assessment | environmental indicators | multi-criteria decision-making methods | product design

Abstract: The paper discusses the problem of the correct identification of the Objective Function and the associated SNR function that designers must choose when employing the Taguchi method in product design, considering this step as the basic element to quantify the uncertainty of the device performance prediction. During product design, when many design aspects must still be understood by the design team, it is important to identify the most suitable “loss function” that can be associated with the characteristic function. The second step considers the variability of the characteristic function. The Taguchi method considers many Signal to Noise Ratio functions whereas in the paper the use of a unique function is suggested for all kinds of loss function. The discussion is argued in the context of so-called parameter design, with the perspective of identifying the best ranges of variation of the parameters that designers have identified as influential on the characteristic function, and also to adjust those ranges in order to obtain twofold results: reduce Bias between the mean value of the characteristic function response and the target value; obtain less variability of the characteristic function. The discussion of a case of study will point out the approach and the use of a unique Noise Reduction function.

Keywords: Loss Function | Noise Reduction | Signal to Noise ratio | Taguchi method

Abstract: To manage the design matrix is an apparently easy thing to do. Discovering incongruences and converging at least towards a decoupled structure could suggest to designers that they have reached a sufficiently good starting point for the product under development. This is not sufficient. To be able to evaluate the information content of that solution is on the contrary an almost difficult activity because many relations between Functional Requirements and Design Parameters may not be completely defined deterministically. Eliminating bias and reducing variance remain the objective to be pursued. The paper discusses a procedure based on the Taguchi method to orient designers when verifying the influence that each design parameter has on the functional requirements. After the association of an Objective Function with one functional requirement or with a macro-functional requirement, the relation between the Objective Function and a set of design parameters can be identified from the Design Matrix. This can allow the designer to discern the best range of each parameter, analysing the Mean Value of the Objective Function and Signal to Noise Ratio. In the case of a conjoint influence of many design parameters on the functional requirement, it is important to verify the mutual interaction among the design parameters and evaluate the kind and level of interaction.

Keywords: Information Axiom | Mean Values and SNR | Robust Design

Abstract: The paper deals with the crucial phase of identification of the problems that occur during the design process of industrial products. Designers need to identify the nature and the importance of the problems. An interesting approach to this purpose is the Axiomatic Design, which is the basis for the further application of Robust Design techniques. Among the latter the Taguchi method can be integrated with Axiomatic Design in order to discern the best values of the design parameters and also those values least affected by noises. The study of the interaction of the parameters can reveal the presence of problems, when decoupled matrices are analyzed. The discussion will be made considering the different scenarios of uncoupled and decoupled design matrices and the different reasoning the designer must use. All the information collected can then guide the designers to pursue the design of the best products.

Keywords: Axiomatic design | Design matrix | Information axiom | Robust design | Taguchi method

Abstract: Mapping among several domains allows different aspects of the design process to be put in relation. Considering that the DSM data structure is able to capture much information of a single part of the product development process, the DMM allows different domains to be linked. The first mapping matrix employed in the design process connects the functional and the physical domain. It describes how the functionalities are explained and by which elements. The Design Matrix of the Axiomatic Design approach is intrinsically a mapping matrix, and describes the relation between functional requirements and design parameters. It is a candidate to be part of the MDM data structure, being addressed to guide the solution to problems during the product design. The paper discusses the nature of the Design Matrix and compares it with the first DMM of the MDM process. On the basis of a case study differences and similarities are pointed out.

Keywords: Axiomatic design | Design matrix | DMM | DSM | MDM

Abstract: The paper is based on the experience matured in ten years of teaching "Product Design and Development" at the Faculty of Engineering of the University of Calabria (Italy). This paper is focused on the consideration that many of the methods employed during product design activity share a matrix formulation as a means of collecting and managing project data and that students must be familiarized with the use of this kind of data structure in a very different way from their previous experiences, because project management can be pursued by mapping information from one method to another. Students are in fact guided to organize data related to the design on which they are involved in order to guarantee that the information can be mapped from one formulation to another, meaning that they have the whole design process under control. Attention will be paid to the pedagogic aspects and problems associated with the way how information can be collected and ranked and how a decision can be made. Copyright © 2012 by ASME.

Keywords: Axiomatic design | Functional analysis | Mapping information among design methods | Teaching functional reasoning

Abstract: The paper describes experiences and reflections, matured at the Faculty of Engineering of University of Calabria (Italy), during the last decade, in the courses of Engineering Design Methods, held at the bachelor degree in management engineering and the master degree in mechanical engineering. The courses, even addressed to different audiences, contain the functional analysis of an industrial product, that characterize the core of the discipline. In the paper the product functional analysis is described and the problems of its teaching are reported. The application to a case of study clarify its use and its employment as tool for discovering lacks in device already present on market.

Keywords: Building of functional net | Functional analysis | Reasoning by function

Abstract: The paper proposes an extension of the Design Structure Matrix to support designers in a rough sustainability evaluation of an industrial device in the early stage of its development. The methodology of assessment is based on an Augmented DSM (A-DSM), where the original DSM layout has been modified to allow developers to record information about product lifecycle and to manage the interactions of product components among them, towards other systems and with the environment outside. After a description of the novel matrix layout, a method is formalized. The proposed methodology will show that product evaluation is achieved by means of a combination of partial results that can be calculated already in conceptual phase: a set of environmental indicators and a couple of sustainability performance values. In accordance with this approach, the method is conceived as sustainability control panel useful to evaluate early environmental performance.

Keywords: A-DSM | Conceptual design | Early assessment | Functional analysis | Simplified LCA

Abstract: In the conceptual design, a product can be viewed as a functional net, defined in the classic active verb-object way, by mean of functional elements and links associated to the flow of energy, material and signals and link of force. In order to assure the validity of the links at different levels, in the paper the graph theory is employed to check the suitability of a functional net, treated as a collection of sub graphs, each defined on a type of link. In order to verify the functional net it is necessary to identify each subnet, characterized by the same kind of link, and check each one using a set of formal relations that represent the feature of each link. Based on these relations a set of controls have been implemented for each subnet.

Keywords: Design process | Doubt based system | Functional net | Graph theory

Abstract: Recently, some web-based tools have been proposed to support both individual designer and design teams in the management of information and in assisting concurrent distributed design activities. The rationale which is often underlying such proposal is to enhance design-manufacturing engineering or product data management (PDM) systems for managing product development as a single integrated business process. The focus of this paper is on presenting a logical model which can drive the conception of tools for supporting the distributed management of design data of mechanical products (DDDM: Design Data Distributed Management). How the model can be fruitfully used to support individual/group technical activities and group organisational activities, especially in the product design review phases during the product development process, is discussed. The main functionality and the client/server architecture of one of these tools is also described, and, lastly, a case of study is reported in order to explain how the model can be applied.

Abstract: In the recent past several studies have been conducted, and several methodologies have been set up to aid the designer in product design development. Another useful development in this field would be tools able to support the designer when he/she is manipulating abstract elements that roughly approximate their final shape and placement in the definitive layout. The paper describes a methodology and a prototype software to support the designer during the conceptual phase. It is based on the creation of a 3D environment, the "design space", where the functional representation of the problem, that the designer has outlined, is increasingly clarified and solved in an architectural lay out of a product.

Keywords: Conceptual design | Creative design | Early phases of design

Abstract: In the present paper a methodology is described whereby the subdivision of a multiply connected planar domain into mappable regions is automatically performed. The technique proposed, which was developed to be applied within an interface between a geometric modeler (b-rep type) and a 3-D BEM code for elastic stress analysis, can be as well applied to 2-D finite element discretization problems. At the present stage of development, the technique operates over planar domains which are externally and internally bounded by polygonal contours and may contain any number of circular holes.

Abstract: Stress intensity factors (SIFs) are computed by the boundary element method for standard compact tension specimens. Traction singular elements are employed along the crack front which enable SIFs not only to be extrapolated from crack opening displacements but also to be directly obtained as problem unknowns. Both straight and curved crack fronts are analyzed: the latter are taken to be in the form of circular arcs with curvature radii ranging from 3.145 to 0.707 the specimen thickness. The influence of Poisson's ratio on the stress intensity factor distribution is also investigated. © 1987 Martinus Nijhoff Publishers.

Abstract: In this paper 8‐node traction singular boundary elements are employed to represent displacement and traction variations in the vicinity of the crack front in three‐dimensional geometries. The numerical procedure suggested for evaluating the singular integrals extending over these special elements is described. The efficiency and accuracy of the special elements and integration procedure are demonstrated by the results obtained in a simple test problem whose analytical solution is known. The interaction of two circular coplanar cracks embedded in an infinite medium under uniform tension loading is also analysed. Finally, the stress intensity factor variation computed for a semi‐circular inner surface crack in a pressurized cylinder is presented. Copyright © 1987 John Wiley & Sons, Ltd