Design Method Of Composite Stiffened Panel For Manufacturing Cost

Composite material has been applied widely in the aeronautic and astronautic area because of light-weight and high-strength. However, the high manufacture cost restricts its further widely application. Reducing the structural weight and manufacture cost simultaneously, and improving the performance price ratio are the main purposes during the research of composite material. In the design and manufacture of composite structure, there is an integrated mould technique which could integrate hundreds of parts into only one part, reducing division, joint, installation time, structural weight, and manufacture cost. Composite stiffened panel is a typical integrated structure used in aircraft. In the early design stage, manufacture cost is the main considered parameter. Establishing a scientific estimation method of manufacture cost is beneficial to select material, optimize manufacture process, evaluate the performance and cost, and realize low cost optimum design. Most of the current research is limited to the structure performance. But there is little research considering manufacture cost as optimum design parameter. This paper mainly considers the balance between manufacture cost and weight of composite stiffened panel. The detailed contents are listed as following.1. According to the structural characters of composite stiffened panel, the estimation method of manufacture time of integrated mould process is presented. By considering the first order dynamic principle and power law, the unknown parameters in the estimation equations are determined. Composite panel with waved stiffeners is studied to verify the accuracy of estimation model for manufacture cost. Moreover, the method of selecting estimation variables is introduced. The theoretical estimation method of manufacture cost for composite stiffened panel is presented.2. The main factors which are related to the manufacture cost during the mould process of composite stiffened panel are analyzed. The cost estimation methods for every parameter are presented. Based on the above discussion, the cost estimation model for composite stiffened panel is established. The three different integrated mould processes for composite panel with T stiffener are studied to verify the applicability of this model. This estimation method is beneficial to direct the design of various composite structures.3. The effect of structural complexity to the manufacture cost is analyzed. The estimation equations of complexity effect for seven typical stiffened panels are listed. According to the practical engineering, the parameters in the estimation equations are modified. Based on the characters of mould process, a scientific estimation method of curing time is presented. Also how the localization for tools affects to time of matching moulds is studied.4. The stability requirement and manufacturability for the design of composite stiffened panel under compressive stress and shear force are analyzed. The theoretical results are compared to the results of ANSYS finite element method.5. The manufacture cost and structural weight are selected as optimum parameters. The optimum design method of composite stiffened panel under compressive stress and shear force is presented. According to the typical forming method of stiffened structure, the detailed process plan suitable for practical engineering is listed. The method of determining the geometrical shape of seven typical stiffeners is introduced. Various factors which affect the optimum design of composite stiffened panel are analyzed based on practical case and the results are matched perfectly. The optimum function of manufacture cost and structural weight are built to realize the low cost design of integrated composite stiffened panel.