Three-dimensional Stress Analysis by a Digital Image Correlation Method and the Three-dimensional Local Hybrid Method

Most measurement by experiment is about a structure surface and it is dramatically difficult to measure the stress state inside a structure. Although the stress analysis of a big structure is possible by the 3-D finite element method, great time, labor, and expense are needed for modeling and calculation. Then, we developed the 3-D local hybrid method which analyzes only the local model of a structure and can evaluate the stress field inside it from surface data obtained by easy measurement. In previous studies, the good result was obtained with the surface cracked specimen subjected to uniform tension and a cantilever subjected to bending. However, with an actual structure, it is not thought that simple bending deformation which is produced under an experiment environment arises. In this study we examined whether the 3-D local hybrid method would be able to apply to the structure subjected to bending and torsion by using the displacement on front surface and the displacement of upper and lower sides of a local model. It was clarified that the 3-D local hybrid method is very useful to the 3-D stress analysis of the structure subjected to the complicated loading (uniform, bending and torsion, etc.).