赤外線ハイブリッドサーモグラフィによる混合モード応力拡大係数へのき裂先端曲率半径の影響

抄録

The Influence of the radius of curvature of the crack tip on a mixed mode stress intensity factor was discussed by three dimensional finite element analyses. As the radius of curvature of a notch becomes large, the inaccuracy of the stress intensity factor becomes large. Therefore, it was elucidated that a notched specimen cannot estimate the stress intensity factor of a mixed-mode accurately. If the mesh of a hybrid analyses domain is made fine, the equivalent nodalforce on an external boundary can be obtained in higher accuracy. The infrared stress images were taken by infrared thermography using the compact normal and shear specimens subjected to seven kinds of mixed-mode loadings, and the data of the sum of the principal stresses were obtained. After estimating nodal forces from the sum of the principal stresses by an inverse problem analysis, the error included in the experimental field was modified by the 2-D intelligent hybrid method. The stress intensity factor was evaluated by the virtual crack extension method and the displacement extrapolation, and the validity of the infrared hybrid method was discussed in comparison with the 3-D finite element analyses.