An experimental and numerical hybrid technique for reconstructing boundary conditions in elastic analysis

A hybrid technique for stress and strain analyses combining experimental and numerical methods reducing experimental error and noise has recently attracted much attention. The previous hybrid techniques involve inevitable error and noise, particularly on the boundary of the target area of interest (TAI). In the present paper, the authors develop a new hybrid technique that can reconstruct boundary conditions from the full-field displacement distribution obtained by experiment. This technique starts from the idea of two matrices based on finite element analysis (FEM). One is the ‘relation matrix’ which gives the relation between displacement vectors on the boundary of and inside the target area. The other is the ‘smoothing matrix’ which ensures smoothness (continuity) of displacement along nodes on the boundary. This technique makes it possible to reconstruct proper or actual boundary conditions on the TAI automatically. Therefore, the distributions of displacement, stress, and strain calculated by the technique are more accurate and useful than those obtained by the previous one not only inside the TAI but also on its boundary.