| The working load of the excavator working device is complicated and changeable, which makes working device produce fatigue damage frequently. As the main component of the working device, boom often occur fatigue fracture and lead to structural failure in practical work. Fatigue damage has become one of the most important factor which affect the overall performance of the excavator. However, the lack of load data in the key components of the working device directly restricts the improvement of the reliability and fatigue life of the excavator, and limits its market competitiveness. In view of this phenomenon, taking the excavator WY230 as an example, this thesis has carried out the research work on the test and compilation methods of load spectrum of boom. The main work is as follows:(1) The geometric relations between the internal objects of working device is analyzed in detail, and the parametric model of working device is created by using the parametric function provided by ADAMS. The forces loaded on each hinge point of the excavator working device are solved with the hydraulic cylinder in different length and pressure.(2) The concept of "Corner Point Method" is introduced and applied to the test of structural stress, and the equations for solving the external loads by the stress at the corner of test section are derived. Then, the correctness of the solving equation is verified by way of laboratory tests.(3) The load time history of the test is compressed, and the amplitude frequency information of the load is obtained by rain flow count. Then the parameter of amplitude is estimated to determine its distribution function. According to the distribution function, the program loading spectrum is compiled.The research on the test and compilation methods of the boom load spectrum will provide theoretical knowledge and experience reference to the further study of excavator load spectrum in the future, and promote the improvement of reliability and fatigue life on excavator powerfully. |
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