Finite element modeling of the bulldozer blade – clay soil interaction

Abstract

Abstract. Purpose. The choice of rational geometrical parameters for working parts is one of the topical problems in the design  process  of  modern  earthmoving  machines.  Nowadays  to  find  soil  cutting  force  it  is  applied  the  experimental  data  –  the  base  for  values of soil resistivity for cutting. However, this parameter depends on many factors that can not always be considered. Therefore it  is required to develop theoretical approaches to modeling of the construction machinery working parts -soils interaction taking into  account  soil  elastic-plastic  properties.  The  purpose  of  the  presented  work  is  to  develop  numerical  solution  methods  for  such  an  interaction problem.  Methodology.  There  was supposed an algorithm  for finite element  modeling of the bulldozer blade-clay  soil  contact interaction considering the soil properties described by the extended Drucker-Prager model in ABAQUS software system. To create  a  soil  model  it  was  applied  the  8-node  C3D8  finite  element.  This  element  uses  linear  interpolation  in  each  direction  and  represents the first-order element. The explicit scheme for integrating of the elements motion equations by time was used. Findings. The distribution of stresses and strains in the soil array for the case of blade horizontal movement was established. It is shown that  the obtained results correspond to the experimental data presented in the investigations of other researchers. There were found the  time-dependences for the driving forces which providing the blade movement with a given velocity for the different cutting layer thicknesses. The analysis  of the blade slope angle influence on the cutting force angle was performed. It was demonstrated that the  two times increase in the blade velocity leads to a need for soil cutting power requirement increase in 2,4...2,8 times depen ding on  the  cut  layer  thickness.  Originality.  There  was  developed  the  method  of  finite  element  solution  for  the  problem  of  the  dynamic  contact interaction between earthmoving machine working part and the soil. The method allows to take into account the peculiarities  of soil elastic-plastic deformation. The influence of the cut layer thickness and the blade slope angle on the value of force ensuring  the soil movement was established.  Practical value.  The application of the developed method allows to optimize the design of the  blade, to choose optimal modes for the machine operation depending on the physical and mechanical properties of the cut soil. The results  also  make  it  possible  to  determine  theoretically  power  requirements  for  the  bulldozer  power  unit  to  ensure  the  highes t  operational efficiency of the construction machines.