Thread joint has serveral advantages such as simple structure, convenient dismounting,various format,reliable joint,good interchangeability,therefore it is widely applied in machinery and engineering equipments.The cause and the anti loosening method of thread joint is researched,And several new anti-Loosening methods of thread are introduced.At the same time,some transverse vibration testing are implemented on a group of thread joints according to the national standard.The result of the test proves the anti loosening effect of several thread joint, and provides some reference for thread selecting in structure design field.

The 2D random road surface spectrum based on the sinusoid superposition method is built, the modified sinusoid superposition method is used to extend 2D road to 3D for providing the modeling process of 3D random road surface spectrum. The forming rule of 3D random road file in automatic dynamic analysis of mechanical system(ADAMS) is expatiated; the altitude matrix in road file is calculated by Matlab programming and the 3D random road file is generated. Simulation results show its availability in simulation research.