抄録
to study on the leak before break, namely LBB criterion of high pressure reactors for polyethylene production, the validity of the stress intensity factor formulas proposed by Newman-Raju, Iwadate et al. and Nakazawa et al. were discussed. When Newman-Raju's stress intensity factor formula without considering the back surface magnification factor is used, the condition of K1≥ KIC(J) gives a good criterion for LBB condition.
