Abstract: In order to study random vibration and running smoothness of logging trailer-truch this paper puts forward a kind of computer simulating method for calculating the random vibrations. Based on five inputs and ten degrees of freedom, a mathematical model of tree-lehgth logging trailertruck is set up. Simulating calculations about a tree-length logging trailer-truck, model LT-110+GT15C, are carried out with the IBM computer. The results of field test correspond with that of theoretical calculations. Therefore, the mathematical model advanced in this paper can be used to predict the running smoothness and optimize structural parameters of tree-length logging trailer-truck as well.

Key words: Logging trailer-truck, Random vibration, Running smoothness