In this paper, the author have developped the elastic-plastic fracture analysis code “FRACT-2D” using the finite element method for evaluating the nonlinear fracture parameter
J-integral of an axi-symmetric crack problems in addition to the
J-integral. Applying this code to the shell-to-bottom junction of a 113, 000kl oil storage tank, the
J-integral of a crack assumed at the toe of the fillet weld was evaluated numerically under the filling and emptying operation of the tank. Then, following results were obtained;
(1) Filling the tank with liquid, the
J-integral coincides well with the
J-integral at the lower liquid level. Futher filling, the difference between both parameters increases gradually and the
J-integral becomes lower than the
J-integral by about 15% when the tank is full.
(2) Emptying the tank, the
J-integral decreases along the history of the filling operation. Then, it takes a negative value due to compressive residual stresses distributed at the crack-tip when the tank is empty
(3) The
J-integral has a path-independence during the filling and emptying operation of the tank.
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