Different function breakdowns for one existing product: Experimental results

Abstract

This paper describes the findings of an experiment on how different engineers understand the notions of function and functional breakdown in the context of design by modification. The experiment was conducted with a homogenous group of 20 design engineers, who had all received the same education. The subjects were asked to analyze how a hydraulic pump works and summarize their understanding in a function tree. The subjects were given either the hydraulic pump itself (with part of its casing removed), or a maintenance drawing that showed a section cut of the pump. This paper shows typical outputs of the designers and discusses the differences between the subjects' approaches and resulting function trees; and points to typical mistakes the subjects made.