FUNDAMENTAL STUDY ON A PARALLEL NUMERICAL ANALYSIS FOR PERFORMANCE PREDICTION OF AGRICULTURAL TIRE BY 3D FE-DE METHOD

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Firstly, the preparation of FE mesh for tire was done. We developed two 3D FE mesh generation programs; one for smoothed tires, and the other for traction tires. Generation of FE mesh for traction tire could successfully demonstrated by using a typical tire data.The capability of DEM to include the effect of wheel lug was also verified by the recent development of 2D DEM program in our Agricultural Systems Engineering Laboratory. The problem of large computational time is expected when 3D DEM program is developed.The possibility of dynamic FE-DE method was investigated in terms of the application in soil-tire system. We assumed that a tire and deep soil layer could be modeled as FEM and soil surface layer as DEM. We developed a combined FE-DEM code to analyze an agricultural tire-soil interaction problem. Simple contact algorithm is adopted in terms of computational speed. Small example problem of vertical tire sinkage on to a deformable soil was analyzed and we found that the sufficient accuracy of analysis for displacement field could be obtained.As for tire rolling problem, it was found that the FE-DEM code could include the function of tire rotation and translation. The result of the basic analysis showed that the deformation could be analyzed qualitatively, but the total vertical reaction exhibited the heavy vibratory result. Further detailed study should be added to this problem.As the one of possible and useful tool, we investigated the possible application of message passing parallel processing for FE-DEM. The following points are clarified.In the developed FE-DEM program, contact check and contact reaction subroutines in DEM are the two most time-consuming parts.If the parallel processing system is introduced, FEM and DEM in FE-DEM program should be allocated to two nodes and there may be possible to devide the contact check loop in DEM into more than two parallel processes.