Strain singular field near the edge of interface in material with cuboidal inclusion based on experiment and numerical analysis
Makoto KASAI, Hideo KOGUCHI, and Takahiko KURAHASHI
Makoto KASAI, Graduate school of Nagaoka University of technology, 1603-1 Kamitomiokamachi, Nagaoka, Niigata Hideo KOGUCHI, Nagaoka University of technology, 1603-1 Kamitomiokamachi, Nagaoka, Niigata
Takahiko KURAHASHI, Nagaoka University of technology, 1603-1 Kamitomiokamachi, Nagaoka, Niigata
Abstruct
In this study, we focus on strain singular field near the edge of interface in three-dimensional joints, and experimental and numerical studies are carried out. The dissimilar material joints are used in various fields such as electric devices, car, aircraft, and cellular phones. Singularity fields for strain and stress occur at vertex on interface in dissimilar material joints, when external load is applied to the dissimilar material joints, and it might be induced delamination or crack. Therefore, it is necessary to investigate singularity field near the interface edge by experiment and numerical analysis to avoid failure of dissimilar material joints.
In this study, a coupon of specimen which silicon chip was embedded in resin is employed, and tensile load is applied to the specimen. Surface roughness of specimen is measured by laser displacement sensor before and after loadings. Step increment for measurement in the tensile and transverse directions of the specimen is 2μm. Load for
specimen is measured by load cell, and this value is used in numerical analysis explained later. Digital Image Correlation Method (DICM) using surface roughness on specimen and cross correlation coefficients for surface pattern was used for evaluating the displacement on the surface. Strain on surface of specimen is calculated by using the Moving Least Square Method (MLSM).
On the other hand, the Element Free Galerkin Method (EFGM) is applied to compute the displacement and strain distributions in the three-dimensional model of specimen. FEM and BEM are frequently used for stress analysis in the three-dimensional joints. BEM is hard to calculate accurately the distribution in the surface of stress and strain.
Furthermore, when the FEM is used to obtain the strain and the stress distributions, it is necessary to take care for mesh generation around interface considering mesh connectivity condition. It is very hard to prepare the mesh data. Therefore, in this study, the EFGM is used to compute the strain distribution in the surface. In the EFGM, the physical values, i.e., displacement, strain and stress, can be obtained by using the displacement data at distributed nodal points. In this study, the specimen model used in experiment is employed as computational model, and strain distribution near the edge of interface is calculated based on the EFGM. Finally, the strain distribution obtained by the DICM and the MLSM is compared by that obtained by the EFGM, and some discussions are made on the condition of experiment.
