Simulating pseudotruss excavating part of excavators

Introduction. Single-dipper hydraulic excavators are becoming widely used multifunctional machines. Upgrading the machine as a whole and its assemblies is an actual problem to be solved with the aim of reducing material consumption and increasing stability and throughput. The article presents results of computer simulation of the excavating part designed to reduce the weight of the equipment. These data can be used to improve the equipment of excavators when operating with non-standard excavating equipment of increased weight. Materials and methods. The excavating equipment of the Hitachi ZX270 excavator is taken as a prototype. Computer simulating and calculation of the excavating part is conducted using the T-FLEX software. The calculation is carried out for different modes of the excavator operation and for different orientations of the jig boom, dipper stick and dipper relative to each other: excavating with the entire width of the dipper, single-tooth excavating, swiveling the loaded excavator for unloading. The highest stresses arise in structural members in the considered calculation cases. The calculations are performed without accounting the oscillations occurring at transient operating modes and during locking. Results. The study determines a stress-deformed condition of the pseudotruss excavating part structures of the excavator with various lightened makes selected on the basis of computer simulation. Zones of the highest stresses and largest deformations are revealed as well as suggestions on their decrease are made. The research results are used to optimize the jig boom and dipper stick structures by the criterion of generated stress minimization. Conclusions. The obtained data and formulated recommendations are the basis for further detailed simulation of pseudotruss excavating part structures of excavators and other machines of various layouts and purposes.