Constraints versus Objectives Example Problem Statement It can be difficult to choose whether a Minimize the take-off weight of the aircraft by condition is a constraint or an objective. changing wing geometric parameters while For example:should we try to minimize cost, satisfying the given range and playload requirement at the given cruise speed. or should we set a constraint stating that cost should not exceed a given level. Sometimes,the initial formulation will need to Question:What is the objective,design variable, be revised in order to fully understand the parameters and constraint? design space. In some formulations,all constraints are treated as objectives(physical programming). System Engineering by J.J.Gao ③cLao 国 21 System Engineering by J.J.Gao ③ctco 国 22 Group Exercise Today's Agenda For your group's system: ■MDO definition 1.Consider the preliminary design phase. Identify: Optimization problem -important disciplines formulation -potential objective functions MDO in the design process -potential design variables -system parameters ■MDO challenges -constraints and bounds 2.Report out System Engineering by J.J.Gao ③ctGe 国 23 System Engineering by .J.Gao ③ctGe 国 24+ - It can be difficult to choose whether a condition is a constraint or an objective. For example: should we try to minimize cost, or should we set a constraint stating that cost should not exceed a given level. Sometimes, the initial formulation will need to be revised in order to fully understand the design space. In some formulations, all constraints are treated as objectives (physical programming). System Engineering by J. J. Gao 21 Constraints versus Objectives + - Minimize the take-off weight of the aircraft by changing wing geometric parameters while satisfying the given range and playload requirement at the given cruise speed. System Engineering by J. J. Gao 22 Example Problem Statement Question: What is the objective, design variable, parameters and constraint? + - System Engineering by J. J. Gao 23 Group Exercise + - 24 Today䇻s Agenda System Engineering by J. J. Gao MDO definition Optimization problem formulation MDO in the design process MDO challenges