CAD System-simulate Grain Design Of Solid Rocket Motor

The traditional method of SRM(Solid Rocket Motor) propellant design uses manual drawing and calculation, it takes a long time and always be limited to some common grain geometry. Computer procedure based on three-dimensional modeling can realize design of grain with random shapes. It also provides data for pre-research and elementary study.In this paper, the object-oriented idea is used to divide complex 3-D model to simple elements and develop a grain design modeling software which is based on VC++ 6.0 development kit.First, after research and analysis on some data models of computer graphs which are used to describe the 3-D objects, choose the boundaries model as data structure.Second, the software frame which is based on MFC is built by using OpenGL interface functions of Windows operating system, and OpenGL graphs can be displayed in it.Third, a series of graph classes are derived from a base graphics class, which can be used to describe the complex 3-D models. By using the Polymorphism characteristic of C++, all graph classes are defined to have the same interfaces for application.Next, some parameterized user interfaces are developed for modeling. Users can design some common grain directly (such as cylinder, cone, platform, and some complex shapes: star, wheel). There are two ways to display the grain: three-dimensionally display and two-dimensionally display, including vertical and horizontal section.At last, the appearance of burning process. The system simulates the real burning process through vertical and horizontal sections as different wrapping strategies.