Function Sharing in Mechanical Design

Function sharing in mechanical design is the simultaneous implementation of several functions with a single structural element. If automobiles were designed without function sharing they would be relatively large, expensive and unreliable. But because elements like the sheetmetal body implement many functions (electrical ground, structural support, aerodynamic faring, weather protection, and aesthetics among others) automobiles perform better and cost less than a non-function-sharing alternative. This paper describes how function sharing can be viewed as a computational design procedure that produces efficient designs from modular designs. The function sharing procedure consists of three steps: 1) a structural element is deleted from the design; 2) physical features that can provide alternative implementations of the function(s) of the deleted element are found; 3) modifications are made to the design to accentuate the desired properties of the features found in step 2. We have chosen mechanical devices that can be described functionally as a network of lumped-parameter idealized elements as a domain for exploring function sharing. Such d evices include pressure gauges, accelerometers, and hydraulic cylinders.