Engineering design and product development research, and teaching based on research insights, has a very long history in German-speaking countries. Like in most other countries (see, for instance, the editorial on the French perspective in May 2011), this area has been mainly situated within mechanical engineering. In Germany, the origins date back to the 19th century and stem from the field of machine elements: Systematic study of machine elements, their design, and analysis led to more general design rules, and from them evolved the “German School” of Design Theory and Methodology (DTM) as it is known today.
This guest editorial focuses strongly on the DTM activities in Germany. However, it should be borne in mind that research work in the field of optimizing machine elements and procedures for their design, analysis, and simulation remain a very strong branch of design research in Germany. Teaching the subject of machine elements is also an indispensible part of engineering education (courses over at least two semesters, usually three semesters during the first 2 yr) everywhere, implying extensive project-like exercises by means of practical examples. The higher value of teaching machine elements is to integrate the contents of other courses, e.g., in technical mechanics, manufacturing technologies, materials—all of this knowledge is needed for designing. At the same time, machine element courses are regarded as a necessary prerequisite for advanced design courses because they teach basic design and dimensioning techniques.
In German-speaking countries, DTM started to become a research and teaching area more than 150 yr ago. A detailed overview about the history and major researchers and schools can be found in the book “The Future of Design Methodology” edited by H. Birkhofer (2011). K. M. Wallace and L. T. M. Blessing also wrote about “An English Perspective on the German Contribution to Engineering Design” in Research in Engineering Design (2000).
Today, courses in DTM are an integral part of the curriculum in almost all Technical Universities in Germany. Books in English language like “Engineering Design” by Pahl and Beitz (first English edition in 1983, based on the German textbook “Konstruktionslehre,” first edition published in 1977) and “Design Science” by Hubka and Eder (English edition 1996, based on their German book “Konstruktionswissenschaft” published in 1992) helped to spread ideas and have influenced DTM worldwide.
Although the initial DTM concepts displayed some differences in background and focus, the researchers succeeded quite early in formulating a common view under the auspices of the VDI (German Association of Engineers). The outcome was the VDI-guideline 2222 (VDI 2222, 1977), later developed into the VDI-guideline 2221 as a basic framework for design processes (VDI 2221, 1986; English version 1987). This is an important reference for many research activities to this day.
Researchers in Western and Eastern Germany used to have reasonably good contacts (and mutual respect for their respective work), even during the “cold war” time. These contacts intensified during the 1980s with a joint series of workshops on “Bild und Begriff” (Image and Concept), which led to two very successful conferences “Designers” and “Human Behaviour in Design.” As a result, there were no real problems in merging the efforts in design research after the German re-unification in 1990.
The core of the work done between the 1950s and the 1970s was the development of procedures, guidelines, rules, and solution catalogues for design processes and their application. That work aimed to enhance design resources and capabilities in practice (in Western Germany the goal was to eliminate what was called “bottleneck design” in the late 1960s) and to make design teachable and trainable.
Important topics have been discussed intensively and methods and models out of this period of time are still in daily use. Examples are the management of alternative solutions, functional modeling or the—now very common—phase model of designing: The design process is divided into several phases (usually: requirements clarification—functions—principle solution—layout design—detail design) in which specific properties of the product being developed are defined, analyzed, modified, and optimized. These phases form the global guideline for the design process, including the iteration cycles among them. Thus, a systematic design process is prescribed that leads from the abstract to the concrete and from the less detailed to the more detailed.
The value of this concept has been demonstrated mainly by application on new product development. The concept has also proven very valuable for teaching design: Since about the 1970s, all German students in mechanical engineering, besides the traditional education in machine elements, are trained in this type of design methodology.
In industrial practice, especially the phase-approach has set the pattern for specialized stage-gate models of the product development process that are commonly used today. Other elements of the “traditional” design methodology were less readily accepted in industry—probably because industry very rarely has new product development cases. On the other hand, researchers in DTM started to thoroughly investigate what to do in cases of variation and adaptive design tasks only in the past one or two decades. Since about the 1980s and still today, there have been discussions on the “gap between design research and design practice” and considerations on addressing it in DTM work. Seen from the scientific point of view, this is more like a positive stimulus to do further research—particularly necessary because the needs in engineering practice have changed considerably over the last two decades.
In the 1980s and 1990s, i.e., decades after the aforementioned phase models of designing had been proposed, empirical design research became a new issue in Design Research. In Germany, research was conducted mainly at TU Darmstadt (Pahl, Birkhofer) and TU Munich (Ehrlenspiel, Lindemann), often in co-operation with social scientists and psychologists (in particular Dörner, Badke-Schaub, Hacker) who could provide vast experiences in empirical investigation and evaluation methods. The results of these studies had a major influence on the further development of DTM and have also influenced design research in other countries (especially in the USA and the UK, as was documented in the two conferences “Designers” and “Human Behaviour in Design” already mentioned above).
In industry, the 1980s and 1990s saw the introduction of Computer-Aided Design and Computer-Aided Engineering tools into the German industry in a big way. The term “virtual product” and “virtual product development” was coined already in 1998 (Spur/Krause 1998). However, the development and introduction of computer tools took place (and, in principle, still takes place) to a large extent without substantial input from DTM and its scientific findings.
In research, during the 1980s and 1990s, DTM increasingly expanded into a methodology for product development. The term “product development” implies both the expansion of products considered, from mechanical to mechatronic to adaptronic to product-service systems, and the expansion of focus, e.g., more flexible procedural models for development processes, computer-support and management of product development, process re-engineering and optimization, integration of design-for-X methods, extensions of design-for-X criteria, simultaneous development of product and production process. At least since the 1970s, there had been some influence of systems engineering on DTM. Focusing on the complexity of products, processes, the environment, the society, etc., and the importance of product lifecycle management fostered research overlapping DTM and systems engineering (e.g., Lindemann, Maurer, and Brown, Structural Complexity Management, 2009).
The representatives of this more holistic approach in Germany (in alphabetical order) were, in particular, Albers, Binz, Birkhofer, Feldhusen, H.-J. Franke, Gausemeier, Höhne, Lindemann, Meerkamm, Weber, and Welp.
A joint effort of several researchers and practitioners resulted in the launch of the VDI-guideline 2206 in 2004. This guideline still is the first and only attempt in the world on a design methodology for mechatronic systems, and it is referenced extensively.
Related research work in Germany also investigates the use of new information and communication technologies in product development, e.g., knowledge management, agent systems, computer-aided optimization. Other work addresses the architecting of complex products or systems. Finally, some design researchers are working on extended methodologies for the design of microscale products where solutions and especially technologies are radically different from the macroworld considered before.
To sum up, at present, there is no such thing as a single “German design research culture.” Instead, a multitude of different extensions and specializations of DTM can be observed—most of it, however, building on the foundations of the classical “German School” of DTM. This is also due to the fact that in Germany engineering research is usually quite closely linked to industrial applications; there are even special funding mechanisms for this type of co-operative research and development projects. These have both advantages (e.g., confrontation of new ideas with industrial needs, team-building of academic and industry researchers in common projects) and disadvantages (e.g., research topics are quite fragmented according to a highly specialized industrial scene, basic investigations may be compromised).
As can be seen from the overview given above, the German tradition of research in engineering design and product development is quite “prescriptive:” Most of the work aims at developing methodologies, methods, tools, guidelines, etc., which can support designers/product developers in industry and/or which can support the teaching of design. Descriptive studies—empirical design research—are seen as an important complement to assess given situations and/or evaluate potential improvements. A mainly or even purely descriptive type of design research is not in accordance with the German traditions in the field. Strengthening the competences and the capabilities of our students as well as of practitioners in engineering design is the overall goal.
As we conclude this editorial, we make some remarks on academic training and qualification and on national as well as international co-operation.
People in German engineering research and especially design research have different backgrounds and statuses compared to other countries as follows:
Practically, all senior researchers (professors) have extensive industrial experience in leading (design) positions—we usually do not have purely academic careers. Achievements in a leading position in industry are seen at least equivalent to higher academic qualifications (e.g., habilitation).
At German universities, professors usually lead quite large groups—between 10 and 50 researchers plus some technical staff. The basic government funding feeds between 20% and 50% of the group, the rest of the funding has to be acquired via projects.
German doctoral (Ph.D.) candidates in engineering are not regarded as “Ph.D. students;” they are employed and fully paid by the university (as so-called research assistants), each one usually responsible to organize and produce results for at least one of the aforementioned projects. Besides research and development work, research assistants also have teaching and administrative duties, e.g., tutoring exercises or supervising design projects. German doctoral candidates are also expected to present and publish autonomously—in their project consortium as well as at conferences or in journals. Thus, a German doctoral (Ph.D.) candidate in engineering (design) learns so-called soft-skills (project management, writing reports/publications/applications, negotiating with colleagues in academia and industry, also leadership and teaching) by doing rather than by following courses.
After the doctoral period, research assistants usually go to industry where their professional and personal skills are quite highly ranked. After 5–10 yr in industry, they may choose to come back to academia if they feel obliged to contribute to research and teaching in the field.
German university researchers in design (as well as in other subdisciplines of engineering) also have a long tradition of co-operation in academic societies; the aim of these societies is to discuss and plan joint research activities and co-ordinate teaching. It was a very important step in 2011 when the two societies who had covered engineering design and product development—one more from the machine elements side, the other more from the computer-support side and both connected via DTM—merged into WiGeP (Wissenschaftliche Gesellschaft für Produktentwicklung/Academic Society for Product Development). WiGeP now has more than 45 currently active university professors (75 including retired members) of design in Germany and neighboring German-speaking countries as elected members. WiGeP also contains a so-called Industrial Circle with 40 design executives of major German companies as personal members.
Today, design research is no more a national topic. Sparked off in the 1980s by the visionary Vladimir Hubka—initiator of the ICED conference series (first one in 1981 in Rome), several workshops and the informal WDK group (Workshop Design—Konstruktion)—researchers from many parts of the world have been brought together. In 2001, with the consent and support of Vladimir Hubka, these beginnings were transferred into the more formal Design Society. This transition was whole-heartedly supported by many German researchers in engineering design and product development, contributing to, but also learning from co-operation with colleagues in other countries, exchanging opinions and approaches, taking part in conferences, workshops and so-called Special Interest Groups (SIGs).
In closure, we regard the series of presenting different views on design and design research in JMD editorials as extremely valuable, and we deeply appreciate the invitation to provide this contribution. Only in this way, we can see and understand different views and approaches in order to overcome mental borders and make ourselves fit for even increased co-operation and integration.