Abstract: The motion of a truck-mounted cylindrical-box and the failure of protection devices under frontal impact condition were investigated by means of finite element simulation. The protection devices were improved with changing the fixed position of the belt and the structure of the retractor. The results show that the previous protection device has a certain restraint effect on the cylindrical container, which suffers less mechanical impact in the frontal collision process at the initial velocity of 50 km/h and below. The previous constraint system has a poor constraint effect, and the cylindrical box has a secondary collision in the frontal collision condition at the initial speed of 70 km/h. The improved constraint system can ensure that no secondary collision occurs in the frontal collision condition of the cylindrical container at 70 km/h. The peak acceleration of the cylindrical box drops to 25g from 60g. Therefore, the safety performance of the improved constraint system is improved.

Key words: vehicle passive safety, frontal impact;, truck mounted container, protection devices, simulation analysis