Optical and mechanical digitizing of engineering structures

Experimental mechanics for finding out stress fields of a metallic structure are quite difficult if the structure surface shape is unknown. For alleviating it, numerical techniques such as finite element methods (FEM), have been employed. Three-dimensional structure modeling is required before using FEM. However, for complicated structure shapes the 3D modeling is time consuming. Then, analyzing real engineering structures with FEM requires their geometrical coordinates that can be linked to FEM through a commercial CAD package. In this paper optical and mechanical methods for digitizing 3-D structures are described. The systems can be automatically linked to a CAD system which sends the 3D files to a FEM software for stress analysis.