抄録
To evaluate the 3-D stress field inside the specimen from displacement data on the free surface obtained from the 2-D intelligent hybrid method, we developed the 3-D local hybrid method based on the inverse problem analysis. The accuracy of the 3-D local hybrid method varies depending on the depth of the plane of error assessment, hybrid domain size and specimen thickness. Hence the optimal analysis condition was discussed for the acrylic homogeneous material and the acrylic-aluminum dissimilar material. The 3-D local hybrid method can estimate the stress intensity factor with high accuracy, if error assessment is carried out between the displacement matrix at 1.5 mm depth of the 3-D local hybrid model and the modified displacement data obtained by the 2-D intelligent hybrid method from the displacement data measured in the experiment. Accurate analyses can be conducted if hybrid domain size is taken more than two times of the thickness of the specimen with a straight crack of homogeneous and dissimilar materials. The stress intensity factor at the central part of the specimen can be estimated with less than 1.0 % error. The 3-D local hybrid method can evaluate the stress field inside the specimen of homogeneous material with high accuracy. On the other hand, in dissimilar material, accuracy goes down slightly. In an actual structure, a surface crack occurs in many cases. Then, the applicability to the surface crack problem of the 3-D local hybrid method was examined.
