This paper presents a new correlated methodology for engineers to develop a specific vehicle-Unimog associated with a unique structure of movement transmission. A complicated multi-body dynamic model which includes the front/rear axle suspension with thrust tube and coil springs, the steering system, tire and road exciting model is established based on the virtual reality (VR) technology. The topology and kinematics relation of the whole system are analyzed firstly, then the proper constrain pairs are applied among them to satisfy the amazing flexibility and ride comfort of the real vehicle. To more accurately model the real system, some key parameters are acquired by the way of experiment and prediction, respectively. And a triangle function method which combined the inverse Fourier and discrete random producer is proposed based on the standard PSD (power spectrum density). Finally, the ride performance has been evaluated on the random road by simulation and field test. The results show that the applied constraint of the model is correct and the kinematics relation matches the actual condition well. The consistency trends both in time and frequency domain for virtual and field test result show that the established model is effective.

FLUENT software was used to analyze the distribution of internal pressure P of elbow with the variation of outlet pressure P0, inlet velocity v, fluid density ρ and the degree of curvature k=R/D during the flow of crude oil in 180 degree bend pipe, to establish 135 kinds of working condition of internal pressure P distribution database. According to the distribution law of the pressure of the inner wall of the elbow under different parameters (P0, v, ρ, k), calculation formula of the internal pressure distribution of the pipe is analyzed and fitted by 1stOpt software. Through the numerical simulation results of 11 kinds of working condition of FLUENT, the calculation precision of the formula was verified (Maximum relative error). It provides basis for design of bend pipe and safety evaluation of pipeline in high pressure, high flow rate and long distance petroleum pipeline.