STRUCTURAL DESIGN OPTIMIZATION OF SHORT-FIBER COMPOSITE PARTS CONSIDERING MANUFACTURING ASPECTS

摘要

Injection molding of short-fiber composite parts is recently gaining importance. This is reflectedrnby the fact, that about eighteen percent of all carbon fibers are produced as short fibers, of whichrnmore than nine out of ten are processed by injection molding. However, designing short-fiberrncomposite parts necessitates the consideration of both, mechanical as well as process aspects so asrnto yield an optimal structural performance. The latter aspect is especially challenging, since thernmolding process has for instance a strong imprint on the mechanical aspects through determinationrnof fiber orientations. This marks the challenge addressed in this paper; namely, to set up arnmathematically profound optimization framework, capable of simultaneously regardingrnmechanical and technical aspects. For this sake, a general optimization strategy, based on coupledrnstructural and fluid simulations, is developed and discussed. Its numerical performance will bernassessed based on the optimization of an industry relevant composite part; the engine bracket.rnUltimately, the obtained optimal structures will be post-processed exploiting so-called shadowrnprices, allowing for instance an extrapolation of the objective value with respect to design criticalrnrequirements or extensive sensitivity studies with respect to the material parameters, togetherrnaggregating in elaboration advices indicating optimal design revisions.