Simulation Research For Ride Comfort Based On Parallel Computation

Parallel computation means that an application is resolved into multi-subtasks on a parallel computer, and subtasks are assigned to different processors. Each processor cooperates with each other and concurrently executes the subtasks. So in this way, it can realize the purpose of accelerating the speed of calculating or advancing the scale of calculating.The method of parallel computation has quickly developed since it was invented. It has been so highly being valued abroad that it has been successfully used in many fields, such as scientific research, engineering technology and military. It can efficiently accelerate the speed of calculating and resolve the problems that can't be resolved in serial computation. It is the basic tool to resolve the calculating ability. It has become a trend to solve the scientific calculation and engineering physical problems by using parallel computation. To research the application of parallel computation on simulating research of car ride comfort can horizon the ideas of research and get some experience for the application of parallel computation on vehicle engineering field.In this paper, the research was done surround the application of parallel computation in simulation and research of automobile ride comfort. The major research content and related conclusion of this paper are as follows: (1) The instruction of parallel computation platformFORTRAN+MPI were used to make the parallel program. So at first, based on the documents, the research on the related knowledge of MPI was done. Then the research on the installing and using method of the software MPICH2 in Windows operation system was done, as well as the research on the conformity method of MPICH2 and Compaq Visual Fortran 6.6. At last, the situations of PC cluster, which is used to run the parallel program and the hardware and software installed on it were introduced.(2) Basic mathematic calculating research on parallel computation According to the current basic computation method (including: matrix-vector multiply; matrix multiply; numeric integral; the solution of system of linear equations; direct integral of structure dynamic equation), normal computation methods were used. By serial researches and analyses, the programs were developed. Finally, the validity of the parallel computation was tested using examples on PC cluster. And the conclusion is drawn: it is not true that the more the number of processes, the better the accelerating ability. When the number of processes is increasing, the ratio of speedup and the parallel efficiency may be decreasing because of the traffic augment.(3) The foundation of 1/2 plane 6 DOFS vehicle vibration model1/2 plane 6 DOFS vehicle vibration model was made up and the equation of it was deduced according to Lagrange's equation. The frequency response characteristic formulae is deduced, as well as frequency response characteristic,breadth-frequency characteristic,power spectrum density and root mean value formulae of perpendicular acceleration of the body,dynamic flexibility and relatively dynamic load of the wheels.(4) Vehicle ride comfort simulation and research to 1/2 plane 6 DOFS vehicle vibration model in frequency domainThe serial and parallel simulations and researches to 1/2 plane 6 DOFS vehicle vibration model in frequency domain were done. FORTRAN was used to make the serial program. FORTRAN+MPI were used to make the parallel program. The parallel program was run on PC cluster. The relation curves have been drawn, including the relation curves of front and rear seat perpendicular acceleration of the body root mean value and temporal frequency, the relation curves of front and rear dynamic flexibility root mean value and temporal frequency, the relation curves of relatively dynamic load of the front and rear wheels root mean value and temporal frequency. The calculating results of the two simulations are the same and test right each other. The curves of the ratio of speedup and parallel computation efficiency were drawn. The time of the parallel program is shorter than the serial one, and the largest ratio of speedup is larger than 1. This shows that the parallel program has good accelerating ability. When the number of processes is increasing, the time of the calculating is increasing, and the ratio of speedup and the parallel efficiency are decreasing.(5) Vehicle ride comfort simulation and research to 1/2 plane 6 DOFS vehicle vibration model in time domainThe serial and parallel simulations and researches to 1/2 plane 6 DOFS vehicle vibration model in time domain were done. Sine encouragement is used as the rode surface model. FORTRAN was used to make the serial program. FORTRAN+MPI were used to make the parallel program. The parallel program was run on PC cluster. The relation curves have been drawn, including the relation curves of front and rear chair vibration acceleration and time, the relation curves of front and rear dynamic flexibility and time, and the relation curves of relatively dynamic load of the front and rear wheels and time. The calculating results of the two simulations are the same and test right each other. The largest ratio of speedup of parallel program is larger than 1. This shows that the parallel program has good accelerating ability. When the number of processes is increasing, the ratio of speedup and the parallel efficiency are decreasing.