Numerical simulation in applied analysis of the fatigue strength of the support devices of the forestry manipulator

The subject of inquiry is a tractor unit consisting of a wheeled tractor and a hydraulic manipulator. The hydraulic manipulator is installed onto the back console of the tractor with the help of a bracket provided with a mounting plate. The question at issue is low fatigue strength of the mounting plate, which disintegrates approximately after four months of manipulator operation. The purpose of the study is Prevent fatigue disintegration of mounting plate to allow for a sufficiently long period of operation. From finite element analysis, it has been established that excessive stresses occur in the mounting plate during movement on bumpy forest drives. A new design of the manipulator’s mounting pad is substantiated, including an additional device intended to limit vertical movements of the manipulator’s beam. As a result, maximum stress at the mounting pad was reduced in half. Justifications are also given for additional possibility to increase fatigue strength of the manipulator mounting pad by means of minimizing loads onto welded joints.