Trend-Morph-PDS: A Methodology for Innovative (Mechanical) Engineering Design

Abstract

The paper describes a design methodology, TREND-MORPH-PDS, an original contribution to design science. It is a relatively simple methodology that has grown from efforts to innovate mechanical machines with their strong dependence on solid (geometrical) reasoning. The approach focuses on combinatorial methods of invention/innovation/design emphasizing the manipulation of form (as distinct from the manipulation of function alone) that help the designer to generate a wide range of good design alternatives. The first premise of this approach is that the elements and functions of mature technologies such as mechanical machines are well documented and understood. Thus, innovations are more likely to involve new combinations of existing forms than the introduction of new machine elements. The second premise is that valuable information is available about most elements and the more popular subsystems and machines. That information has evolved, sometimes over time spans ranging to hundreds of years, but usually has not been systematically documented and categorised, thus leaving opportunities to investigate these areas and discover good design possibilities. Further, some valuable information is available only anecdotally or is tightly held by the managements of the companies that have manufactured the device(s) or own the intellectual rights. The TREND-MORPH-PDS methodology involves three phases: 1. TREND: Start with a general goal or goals. Break this down into sub-areas/systems, including: socio-economic, near physical environment, power source, prime mover, gearing/matching, transmission, working sub-system and control system. Research and document historical trends in each of these areas and their possible influences on the design. 2. MORPH: Apply morphological analysis to each sub-system, using rapid graphical techniques. Move to detail design for specific alternatives as satisficing sub-systems are identified. 3. PDS: At all times during these stages, take advantage of design knowledge/tools that are currently available, looking for ideas and opportunities. Work constantly on constructing the Product Design Specification (PDS). The conceptual design is complete when the PDS is finalized. Detail design, which would follow from the PDS, is not treated in this paper. We illustrate the methodology with a case study of a morphological analysis of a ground water pumping system suitable for low volume flow pumping.