CAE Technologies Application And Test Study For Operator Guard Of Hydraulic Excavator

The operator protective guards of hydraulic excavator is used to provide a reasonable protection for the operator, which can prevent the driver from the fronting and falling objects. The operator protective guards is composed of front guard and top guard. The front guard is a structure which is used to prevent the driver from the fronting objects. The top guard is a structure which is used to prevent the driver from the falling objects. The study on operator protective guards is very important to ensure the safety of the operator who be prone to injure by the fronting and falling objects.This paper describe nonlinear finite element analyze and test about carrying capacity and energy absorption capability of hydraulic excavator's front guard and top guard. Base on elastoplastic mechanics theory, the finite element model of front guard and top guard is built. Simulation Analysis about transient impact energy absorption and distortion characteristic of top guard is analyzed by large-scale finite element analysis software at first. And then, the static limited carrying capacity and energy absorption characteristic of the front guard is calculated by large plastic deformation finite element method. According to the simulation Analysis results of carrying capacity and energy absorption characteristic on front guard and top guard, the design and analyze method of both structures are discussed, and they are validated by test at last. The results both test and simulation are identical. They prove the correctness of nonlinear finite element analyze, and validate the reliability of design and analyze method that is described in this paper.In this paper, the structure design, theory analysis, computation simulation and test of top guard and front guard are performed. The conclusions are summarized as:(1)The significance of excavator guard is expounded, and the test method of guard is discussed. The basic dynamic plastic deformation theory of computational simulation for top guard is analyzed, and the static plastic deformation theory of computational simulation for front guard is also analyzed.(2)The mechanical properties distinction of planar shaped top guard and curve shaped top guard is discussed. If the number of intermediate support is not increased, it is hard to increase the stiffness of top guard.(3)The design of top guard is improved, and computational simulation and test are performed, both of which show that the improved design can meet the international standards. When computer simulating, the input of material properties and proper simplification of the components connecting must be strictly controlled. When top guard is manufacturing, mechanical characteristics and the pipe diameter, wall thickness or the size and thickness of plate also must be controlled.(4)The design of front guard is improved, and computational simulation and test are performed, both of which show that the improved front guard can enhance the vision performance and the protect property also meets the international standards. Similarly, when computer simulating, the input of material properties and proper simplification of the components connecting must be strictly controlled. When front guard is manufacturing, mechanical characteristics and the pipe diameter, wall thickness or the size and thickness of plate also must be controlled.(5)The protect property of front and longitudinal beam before and after the improvement of front guard is compared. And the results show that the number and arrangement of beam can greatly affect the protect property. The improved front guard can meet the international standards, but the larger separation phenomenon of longitudinal beam occurs, which should pay attention to.(6)Through computational simulation and test observation, we summarize the factors affecting the performance of top guard and front guard: the size parameters of top guard, the distance between DLV and the cab roof , SIP position, the stiffness of cab, the stiffness and number of support, the stiffness and strength of supports and top guard rim connection.The achievements in the paper provide guide for the design and test of operators'guard of hydraulic excavator.