| With the rapid development of country’s economy, construction machinery playsan important role in the modernization. Crawler hydraulic excavator is more widelyused than other wheeled hydraulic excavator because of its good trafficability. There arelarge variable load force the boom, arm, bucket and rotating platform, theperformance of crawler hydraulic excavator, for example the safety and reliability, willbe directly affected. One type of crawler hydraulic excavator is considered as researchobject, transient dynamics characteristics of crawler hydraulic excavator during soilexcavating process is investigated in this paper, regarding that soil’s large cuttingdeformation large deformation, large displacement of soil’s finite element grid due tothe nonlinear contact problem between soil and device. The main work of this paper isas follows:Firstly, based on fluid-structure analysis methods, three numerical algorithms arecompared. The advantages and disadvantages of the Lagrangian and Euler methodsaving solid large deformation problem are pointed out. The results are shown that ALEmethod is more suitable for numerical simulation. The basic control equation of theALE method and the relationship among these three methods are derived and theLagrangian method and Euler method are two special cases and degenerate form of theALE method.Secondly, aiming at the special conditions of soil’s large cutting deformationduring crawler hydraulic excavator excavating soil, FHWA soil model is used toestablish the transient dynamic analysis model. The characteristics of FHWA soil modelfrom constitutive relation, yield surface criterion, excess pore-water pressure behavior,and strain hardening behavior, strain softening behavior and strain-rate behavior in sixtheory areas are discussed. This soil model is point out to be more suitable to simulatethe large cutting deformation of soil. Combining with the characteristics of Kunshanclay and the characteristics of FHWA soil model, the value of key parameters of soilmaterial are determined. A simple model of two bucket teeth cutting soil is built and tobe verified that the ALE method and the FHWA soil model can be collaborated tosimulate the large cutting deformation of soil.Finally, the transient dynamic characteristics of crawler hydraulic excavator duringsoil excavating process are researched. The effective Von Mises stress distribution of boom, arm, bucket, rotating platform and soil are obtained. The deformation charact-eristics of soil is also gotten. The stress distribution of crawler hydraulic excavator’s keyparts is revealed during the process of soil excavating. The results can be aided to carryout structural optimization design and analysis fatigue life. |
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