Abstract: A car engine hood is selected as the research objective, which uses carbon fiber and glass fiber hybrid composites to replace metal materials, then takes multi-phase optimization method based on Optistruct technology.In the stage of conceptual design, obtain the overall distribution of composite materials by free size optimization;in the system design stage, to obtain the accurate thickness of composite each angles by size optimization;in the detailed design stage, through the stacking sequence optimization of optimal stacking sequence of manufacturing process requirements.Optimization results show that the mass of car engine hood is 13.39 kg, the mass of car engine hood is reduced by 60 % to 5.36 kg with meeting the design requirements after multi-phase optimization.

Key words: composite material, engine hood, multi-phase, optimization design