The weakest t-norm based intuitionistic fuzzy fault-tree analysis to evaluate system reliability

► Weakest t-norm based intuitionistic fuzzy FTA is presented to obtain reliability interval of the system. ► The most critical system component that affects the system reliability is found out. ► Tanaka et al.'s fuzzy fault-tree definition is modified. ► In numerical verification, a malfunction of the weapon system “automatic gun” is presented.