A COMPUTABLE FASTENER REPRESENTATION TO SUPPORT COMPUTER-AIDED CONFIGURATION DESIGN FOR THE LIFE CYCLE

摘要

Most of a product's life-cycle characteristics aredetermined during the configuration design stage, when theproduct's components are selected and arranged spatially andlogically. One set of choices that determines many life-cyclecharacteristics is fastener type selection. In this paper, anassembly modeling representation is presented that supportschanges in fastener types and fastening mechanisms whilemaintaining consistent degrees-of-freedom among fastenedcomponents. A fastening mechanism template and acorresponding instantiation algorithm have been developed fortensile-compressive fasteners. The template consists of fourmain elements: an assembly representation template, CSGtree fragments (to allow geometry construction), geometricconstraint templates, and a parametric relationship template tointegrate analysis equations into fastener models. Eachparticular fastener type is modeled by a specific template thatis developed manually using the general template as a guide.The instantiation algorithm maps a particular fasteningtemplate onto an existing assembly model (assemblies,components, geometry, and mating relationships) in order toadd fasteners to a product. A similar fastener substitutionalgorithm enables the replacement of one fastener type withanother. The use of the algorithms is illustrated in theconfiguration design of an automotive center console. Thepaper concludes with a brief demonstration of how fastenerselection affects life-cycle product characteristics.