Method of the strength analysis of a track-type tractor undercarriage with the use of multibody simulation and fininte element analysis

Abstract

The wide use of the finite element method for the strength analysis of the undercarriage elements requires a reliable method of the load's calculation. Conventional analytical method of the load's calculation does not take into account their redistribution due to the kinematics and dynamics of the elements. An alternative option is the numerical dynamic analysis with the use of the spatial dynamical models taking into account kinematics and flexibility of the undercarriage elements. The article describes a method of the strength analysis of a tracked vehicle undercarriage for the case of a track-type tractor with gross weight 72 ton. The method is based on the combination of the undercarriage multibody model for the simulation of the loads in typical operation modes and finite element models of its parts for calculation of the strain-stress and margin of safety in each load case. The undercarriage is described as a set of rigid bodies connected by springs and dampers at all interaction points between the undercarriage elements, the track-shoes, and the ground. The loads on the undercarriage are calculated by the numerical integration of the equations of motion. The time histories of the loads are used for the detection of the static strength critical load cases. Each critical load is transmitted to the finite element models of the analyzed undercarriage parts for the subsequent strength analysis. The method is demonstrated for the «tractor forward pitch during the lifting of the earthmoving blade» and «tractor moving over a single rail» load cases. The article shows the analysis of the time histories of the bogie loads. The authors discuss issues of the load transmission from the multibody model to the finite element models of the undercarriage parts and demonstrate some results of the strength analysis of the bogie.