Keywords: boundary element method, frames, object oriented programming, computer aided design.

This paper describes an academic structural analysis system called AMATE for planar and space frames. The paper structure is divided into four main parts: pre-processing, processing, post-processing, and a numerical application. In first part the changes done in the original AutoCAD environment (that provides only drawing capabilities) are described. These are required in order to incorporate the remaining boundary element method (BEM) input data (mechanical properties, element connectivity, loading and boundary conditions, etc.) into the drawing information. At this point in the text, the discussions are driven to incorporate of a lot of customized menus for pre-processing and other tools into the standard AutoCAD environment. For example, a detailed explanation is done to help the selection of a command path on AMATE pre-processing menu in order to prescribe boundary conditions, loading, and so on. Then, the next topic is the processing stage. Firstly the mathematical representation of frame by a boundary element methodology is discussed. All local integral equations for stretching, bending and torsion problems of a bar are separately presented. Then, these problems are properly gathered in accordance with planar or space frame case. In addition, a convenient strategy to obtain the global influence matrices of the frame from the contribution of each local integral equations of a specific bar is described. To end the processing stage, part of the class diagrams and the BEM functions implemented in C++ are described and special attention is paid to the specific function developed in this paper called "solver". This function is defined as a main function that uses methods and objects from the ObjectARX library (AutoCAD graphical manipulations) and AMATE++ (structural library for frame BEM calculations). Then, in the post-processing section, numerical and graphical outputs are shown when the libraries are run in order to complete the analysis without quitting the customized AutoCAD environment. Finally, an example of a four-story space frame for AMATE application is shown in order to illustrate the feasibility of this academic customized package. Both graphical and numerical (dialog boxes) outputs are shown. Hence, all stages of analysis namely pre-processing, processing and post-processing are completely integrated within a single analysis environment.

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