Research And Development Of Space Shell Strucre System Based On Objectarx

Shell structure is a main sort of the long span buildings and the large spacestructures, with high rigidity, light weight, rich and beautiful shape, goodcomprehensive technical and economic indicators. With the development of nationaleconomy, shell structure has been widely used in various buildings. Due to thecomplexity of the shell structure, at present, the computation and design of shellstructure are completed by computer aided design (CAD) software on the whole.According to the requirement of the Technical specification for latticed shells and Codefor design of steel structures, development and studies on shell space structure CADsystem are made on the base of existing achievement in this thesis. This paper discussesproblems of the structural calculation, optimum design and working drawing of thestructure. The second development of technology of CAD is introduced to theobject-oriented finite element program design, forming the basic software framework.ObjectARX is a brand-new tool for AutoCAD secondary development based onobject-oriented method. It makes secondary development of AutoCAD convenient andpowerful by means of Visual C++. With the powerful tool, it is possible to develop aCAD software, which is applied to data processing and structural analysis based ongraph operation system.The shell space structure CAD system (SHELL—CAD system) in this thesis takesAutoCAD2002 as the graphic supporting platform and ObjectARX2002 as thedeveloping tool. The system is implemented by the Visual C++ programming techniqueunder the Windows operating system, the MFC foundation class library and othertechniques. The SHELL—CAD system has three modules, which are pre-processmodule, the finite element calculation module and post-process module respectively.Pre-treatment program is established by ObjectARX2002, which developes amenu-driven function to avoid the user to remember cumbersome commands anddevelopes the User Interface based on MFC to meet habit of engineers and designers.On the other hand, this module completes these tasks, collecting data by dialog boxes,the information of the nodes, the member elements and the loads are obtainedautomatically. On the other hand, this module can collect data by dialog boxes andobtain automatically the information of the nodes, the loads and the member elements,the call from the finite element calculation module and post-process module. The finite element calculation module deals with structural computation and section checking, andgets node displacement and internal force. Moreover, this module uses the optimizationmethod with the combination of the direction searching and full stress criteria method toselect the cross-section of the poles and the volume of the joints. The post-processmodule is in charge of drawing in the AutoCAD environment, exporting material listand the total weight of the steel, etc. The entire system takes AutoCAD2002 asdevelopment platform, so it not only continues to use powerful graphical function andbetter user interface of AutoCAD but also has relatively better stability and efficiency.