Advanced Composite Materials (ACM), such as Carbon Fiber Reinforced Plastics (CFRP), have a big potential for achieving a light-weight marine structure. However, material design, structural design and fabrication technology should closely be entangled in achieving a significant weight saving. For this reason, the present paper aims at developing a computer aided design and manufacturing system for advanced composite marine structures.
As the authors had applied the concept of CAD/CAE/CAM technology to design, manufacture and evaluate of an ultra light-weight sailing dinghy, we had pointed out that a general-purpose CAD/CAE had some problems in handling anisotropic laminated composites. Definition of orientation angles, structural analysis of sandwich shells and interface between CAD and CAE are such examples. As general-purpose CAD/CAE systems are developed mainly for isotropic materials, some specialized CAD/CAE systems suitable for anisotropic laminated composites are required to be developed.
First, in this paper, some basic concepts are presented for developing a CAD system of laminated materials for marine structures. In the concepts, a laminate is defined on surfaces with the use of surface-oriented coordinates, and compared with ordinary CAE defined laminates on finite elements. Furthermore, mesh generator suitable for anisotropic materials and interfaces from CAD to CAE, and from CAD to CAM are required in handling laminated composites.
Second, some prototypes of CAD system for laminated panel design are demonstrated, which are programed by one of the object oriented languages, C++. It is shown that object oriented language is effective for defining laminate sequences, because of its function of class definition and its easiness to change classes. In the developed system, a layup sequence is defined on the surface with the use of surface-oriented coordinate.
Third, some prototypes of CAE system for laminated panel are demonstrated, which are made of preprocessor, analysis code and postprocessor. In this paper, general-purpose finite element analysis program MARC is used as analysis code. The designed laminated panel is divided into finite elements concerned with material axis of anisotropic material, that is, fiber direction. The analysis results are displayed on every layer of all region and compared with ordinary post processor in which the results can be displayed on only one layer. It shows that the developed system is effective in designing and analyzing laminated panels.