Experiments for derived factors with application to hydraulic gear pumps

Abstract

For experiments on mechanical products composed of several components, such as a hydraulic gear pump, conventional methods of designing and implementing factorial experiments can be impractical because of the prohibitive costs of obtaining certain components with factors set to prespecified values. A further difficulty is that often some of the factors that are believed to influence the product's performance are not features of a single component but are derived as functions of the dimensions of several components arising from the product's assembly. Experiments are proposed which use a sample of measured components to explore the influence of such derived factors. An algorithmic method for obtaining efficient designs is presented and applied to finding plans for studies on the gear pump. An experiment on the pump is described which involved both conventional and derived factors. This experiment led to new knowledge on how to improve the engineering design of the pump and, in particular, on how to improve its robustness to the varying pressures that are experienced in operation