OPTIMAL MODEL-BASED DECOMPOSITION OF POWERTRAIN SYSTEM-DESIGN

Optimal design of large engineering systems modeled as nonlinear progr amming problems remains a challenge because increased size reduces rel iability and speed of numerical optimization algorithms. Decomposition of the original model into smaller coordinated submodels is desirable or even necessary. The article presents a methodology for optimal mod el-based decomposition of design problems, whether or not initially ca st as optimization models. The overall model is represented by a hyper -graph that is optimally partitioned into weakly-connected subgraphs s atisfying partitioning constraints. The formulation is robust enough t o account for computational demands and resources, and the strength of interdependencies between the design relations contained in the model . This decomposition methodology is applied to a vehicle powertrain sy stem design model consisting of engine, torque converter, transmission , and wheel-tire assemblies, with 87 design relations and 119 design a nd state/behavior variables.