Page 25 - programme book

KEYNOTE SPEAKER:

Intensity of Singular Stress Field (ISSF) Variations for Cracks and
Adhesive Joints Based on Three-Dimensional Theory of Elasticity

Nao-Aki Noda

Department of Mechanical Engineering, Kyushu Institute of Technology, Kitakyushu, Japan

noda@mech.kyutech.ac.jp

Abstract. In this talk, several variations of the intensity of singular stress field (ISSF) are discussed for
three-dimensional cracks. A singular integral equation method is applied to calculate the stress intensity
factor along crack front of 3D surface cracks. Stress field induced by body force doublet in a semi-
infinite body is used as a fundamental solution. Then, the problem is formulated as an integral equation
−3 . In solving the integral equations, the unknown functions of body
with a singularity of the form of
force densities are approximated by the product of a polynomial and a fundamental density function,
which is the exact density distribution to make an elliptical crack in an infinite body. The calculation
shows that the present method gives the smooth variation of stress intensity factors along the crack front
and crack opening displacement along the crack surface for various aspect ratios and Poisson's ratio.
Other examples of ISSF variations are shown for prismatic adhesive bonded problems. In this case, how
to obtain the accurate ISSF variation by using the finite element method is explained.

15